Why New England Winters Won't Freeze Your ADU Plans

There is a common myth in New England that the construction industry simply hibernates from December to April. Most homeowners assume that once the ground freezes, any dream of building a backyard home has to be shelved until the first thaw. But at Backyard ADUs, we operate with a different cadence. 

We believe that housing needs don’t take a break just because it’s snowing. Whether you are looking to create a space for an aging parent to live nearby with dignity or you're looking to build income through a rental, waiting six months for "better weather" is a delay most families can't afford.

Because we use modular construction and specialized site techniques, we can build, deliver, and complete your Accessory Dwelling Unit (ADU) right in the middle of a New England winter. Here is exactly how we beat the frost and keep your project moving toward our 12-month move-in goal.

1. Building in a Climate-Controlled Environment

The biggest advantage of our process is that the majority of your home isn’t actually built in your backyard. Instead, it is built in a dry, warm, indoor facility.

Traditional "stick-built" construction in the winter is a nightmare. Lumber gets wet, freezes, thaws, and warps. Workers are fighting the elements, which leads to mistakes and slower progress. 

By utilizing off-site production, we ensure:

• Material Integrity: Your home’s framing and insulation never see a drop of rain or a flake of snow.

• Precision: Our teams work in a lit, heated environment where they can focus on the quality our brand is known for.

• Consistency: While a blizzard might shut down a traditional job site for a week, our indoor production line never stops.

2. Foundations That Defy the Frost

The most frequent question we hear is: "How can you dig a foundation when the ground is frozen solid?"

It comes down to specialized engineering and a bit of New England grit. We use ICF (Insulated Concrete Form) blocks for our foundations. These are essentially high-density foam Legos that stay in place after the concrete is poured.

• The Dig: If we are starting in the dead of winter, we can "dig out" the frost. We remove the frozen top layer of earth and replace it with frost-free fill.

• Ground Insulation: We apply ground insulation to ensure the frost never has a chance to creep back down below the footings.

• The Pour: Because ICF blocks are insulated, they protect concrete from freezing while it cures. We also utilize frost blankets to trap the heat generated by the chemical reaction of the curing process. This ensures your foundation reaches its full structural strength even when it is 10°F outside.

3. Indoor Progress: The Winter Design Phase

While the snow piles up outside, the "red tape" and planning phases of your project can move at full speed from the comfort of your own home. Our Design & Planning Process typically takes 8 to 16 weeks, and winter is the perfect time to knock this out.

The winter months are ideal for:

• Predesign: We verify your Feasibility Study, complete preliminary engineering, and engage with town officials and utility providers.

• Active Design: This is when you browse design options and choose a starting path. You will finalize a design where the walls are no longer moving and confirm the exact location on your property.

• Material Selections: You will meet with our team to pick out colors and materials.

• The Final Packet: We complete all engineering and finalize your construction contract pricing. Once this is signed, your project cost is locked in.

By spending the winter months in the design phase, you ensure that your project is "shovel ready" the moment we have a weather window.

4. The "One-Day" Set Strategy

The most exciting day of any project is "Set Day," when the crane arrives and your backyard home goes from a foundation in the ground to a standing house. In the winter, we are tactical about this.

We closely monitor the weather to find a clear window. Because we handle the "red tape" and the set work in-house, we have the flexibility to shift our schedule by a day or two to avoid a major nor'easter.

To keep everything bone-dry during transit, every module is wrapped in heavy-duty industrial plastic. This wrap is only removed the morning of the set. Within a few hours, the modules are bolted together, and the house is water-tight day one.

5. Getting the Heat On Fast

A house is just a box until it has a heartbeat. In the winter, that heartbeat is the HVAC system.

Part of our "Full-Service" promise is that we do not leave you hanging with the utilities. We work months in advance to coordinate with local power companies. Our goal is to have the electrical connection ready so that soon after the house is set, we can turn on the high-efficiency heat pumps.

Once the heat is on, our team can complete the final stages in total comfort, and prevent anything from freezing, ensuring that the final result is perfect.

Why "Winter Proofing" Matters to You

Backyard ADUs exists to make it easier for people to live close to the ones they love. 

If your family needs a safe, accessible place to live, telling you to wait until May isn't an option. By mastering the New England winter we can fulfill our mission and provide housing year-round. 

Massachusetts Court Affirms: Separate Sewer Connections for ADUs Cannot Be Mandated

At this year’s Massachusetts Housing Partnership (MHP) 18th Housing Institute, held June 4–5, 2025, in Worcester, housing professionals and municipal leaders gathered to chart the future of housing in the Commonwealth. One of the most impactful developments discussed didn’t come from a new policy or legislative announcement—but from the courts.

During the breakout session, “From Policy to Practice: Understanding & Implementing the Commonwealth’s ADU By-Right Law,” legal experts and planners highlighted a major judicial ruling that reshapes how towns and cities approach accessory dwelling unit (ADU) regulations: a Massachusetts court has ruled that municipalities may not require separate utility connections—specifically sewer lines—for detached ADUs.

The Court Decision That Changes the Game

The ruling stems from a case that challenged local zoning bylaws requiring all detached ADUs to install independent sewer hookups, regardless of site context or capacity. The court found these requirements to be in violation of state law, specifically 760 CMR 71.03(3)(b)(3), which outlines the implementation of Massachusetts’ by-right ADU law, in effect since February 2025.

According to the regulation, municipalities cannot impose additional permitting or infrastructure requirements unless:

• They are required by the regional or local utility provider, or

• Mandated by other lawful authority, such as public health or environmental regulations.

The court’s February 2025 decision—now referenced in guidance by the Attorney General’s Office—firmly stated that requiring blanket separate sewer connections is an unlawful barrier to ADU development. The decision also clearly enforces that municipalities cannot require extra parking, or require attached ADUs only, or disallow ADUs to be added to lots with more than one existing structure.

What This Means for Municipalities

For local officials, planners, and permitting staff, this ruling is a wake-up call. Towns that currently require separate sewer or water connections for ADUs—especially in their zoning or Board of Health regulations—must now amend those rules to align with state law. Failure to comply may result in Attorney General disapproval or legal challenge.

As panelist Margaret Hurley, Senior Counsel for Housing and Municipal Law at the Attorney General’s Office, emphasized: municipalities may tailor design and development standards to local needs, but cannot create financial or regulatory burdens that block the intent of state law—namely, to make ADU development simple, predictable, and affordable.

Why It Matters

Sewer connection requirements often cost thousands—sometimes tens of thousands—of dollars. Eliminating this barrier not only makes ADUs more feasible for average homeowners, it helps fulfill the law’s broader mission: unlocking gentle density and increasing housing supply without displacing community character.

As Massachusetts grapples with rising housing costs, aging populations, and shifting household needs, small legal and policy victories like this one play an outsized role. The message is clear: the Commonwealth is committed to making ADUs an accessible, practical option—and municipal red tape won’t stand in the way.

Key Takeaway

The Massachusetts court ruling affirms that municipalities cannot require separate sewer connections for detached ADUs unless mandated by a utility or lawful authority. This decision removes a significant cost barrier and strengthens the foundation of the state’s by-right ADU law, empowering more homeowners to build and benefit from accessory housing.

The court also ruled on several other cases that challenged local zoning bylaws affecting ADU’s which can be found here. 

The complete 760 CMR document can be found online here.

Rockland, Maine Lowers Housing Costs by Revising Sprinkler Requirements

In a decisive step to lower construction costs and encourage new housing development, the Rockland City Council voted 4-0 on February 10, 2025, to amend its sprinkler requirements for new one- and two-family homes. The ordinance, which will take effect in 30 days, aims to reduce financial and regulatory barriers, making homebuilding more affordable while maintaining fire safety standards.

Key Changes in the Ordinance

The amendment to Chapter 4 of Rockland, Maine’s ordinances removes the requirement for automatic sprinkler systems in certain residential buildings, provided they meet at least one of the following conditions:

• The dwelling is located within 1,000 feet of a fire hydrant.

• The home is under 1,500 square feet.

• The building meets specific fire-resistant construction standards.

These changes are intended to lower upfront construction costs and encourage more small-scale housing development, helping to address the local housing shortage.

By passing this ordinance, Rockland, Maine is taking proactive steps to remove unnecessary regulatory hurdles and support the construction of much-needed housing. This measure aligns with broader city efforts to increase housing availability, encourage development, and create a more affordable and accessible living environment for residents.

With the new law set to take effect in March 2025, Rockland’s decision highlights a growing movement among municipalities to rethink building regulations in favor of practical, cost-effective housing solutions.

Balancing Fire Safety and Housing Affordability: The Data Doesn’t Support Sprinkler Requirements

Fire safety remains a priority, but Rockland’s ordinance amendment reflects a more practical and data-driven approach to regulation. In 2023, Maine recorded 29 fire-related deaths, highlighting the importance of fire prevention. However, when compared to other risks:

• Falls accounted for 29 deaths in 2022.

• Firearm suicides totaled 154.

• COVID-19 caused 798 deaths.

While it’s true that sprinkler systems increase the likelihood of surviving a fatal fire by 97%, fatal fires are not that common—especially in new construction. Modern building codes already require fire-resistant materials, hardwired smoke detectors, and strict egress standards, significantly reducing the risk of a fatal fire compared to older homes.

The current local rules requiring sprinklers on ADUs and other small homes are a major barrier to building housing in Maine. Sprinklers can add $15k-$35k to the cost of a new Accessory Dwelling Unit or small home. Already, it’s very difficult to build an ADU that can cash flow with local rents, and expenses like sprinkler often push the budget to a level where the housing just doesn’t get built. Sprinklers are not required by state building codes on one and two unit buildings. The data shows the probability of a 1 or 2 family home burning each year is .0015%, and while smoke detectors vastly increase the safety of a home, sprinklers provide almost no reduction in fatalities. When you focus on newly constructed, all-electric, super tight homes, the chances of a fatal fire are very low. 

Recognizing this reality, the Maine Legislature is now considering statewide reform through "An Act to Reduce Housing Costs by Not Requiring Fire Sprinkler Systems for Single-family Homes and Duplexes" (LD 629). This bill would prohibit municipalities from mandating sprinklers in these types of residential buildings, aligning Maine with New Hampshire and 22 other states that have rejected blanket sprinkler requirements.

Supporters argue that alternative fire safety measures and responsible building practices can effectively mitigate risk without imposing costly and unnecessary sprinkler mandates. For example, New Hampshire, which has no mandatory residential sprinkler laws, recorded only 12 fire deaths in 2023—demonstrating that rigid regulations don’t necessarily equate to better safety outcomes.

By removing this requirement for small, well-situated homes, Rockland is taking a balanced approach that prioritizes both safety and housing affordability. If LD 629 passes, the entire state could follow suit, helping to lower construction costs and increase the availability of affordable housing without compromising fire safety.

Will Maine take this next step? We will all find out soon. Stay tuned. 

Resources:

LD 629

City of Rockland, Maine website. Chapter 4. Article II Fire Prevention and Safety, Page 4

Maine report points to Modular to save on Housing Costs

Maine's ambitious goal to construct over 80,000 housing units by 2030 necessitates innovative approaches to enhance affordability. A recent analysis commissioned by the Maine Affordable Housing Coalition and written by Sarah J. Sturtevant, titled "Field Notes II: Can Construction Technology Improve Affordability?"  interviewed over twenty people representing developers, suppliers, manufacturers, contractors, designers, and regulatory groups, and asked, “Might greater adoption of new(er) construction technology bridge the gap between construction costs and what most Maine households can afford?” The answer is a qualified “yes”. Newer methods can reduce costs, and there are barriers to address. 

The Advantages of Modular

Sturdivant investigated the potential of three technologies: uninsulated exterior wall panels, insulated panels, and modular construction, to reduce the cost of housing in Maine. She concluded “Modular components have the most promise and the most barriers. Depending on whether the state is able to reach a higher level of standardization, Maine could see cost savings of 10-35% of total costs from the greater utilization of modular.” Benefits of modular include:

• Quality and performance from building in a controlled environment

• Better utilization of Maine’s workforce

• Less seasonality

• Faster

• More ergonomic construction for workers

• Less waste going to landfills

She adds, “Barriers are extensive, including the same code-enforcement issues as insulated-panel construction; double sales tax is charged on modular units and the licensing requirements have not coordinated with training programs resulting in lack of human capacity. Overall, there is a lack of industry knowledge about the opportunity of factory-built components … New(er) technology is an important tool in the tool kit and it is worth addressing the remaining barriers to broaden adoption.”

“Root Causes” Why is it so hard to build lower-cost (aka affordable) new homes?  

In the “Root Causes” section of the report, the writer points out that: 

• There are dozens of organizations (public and private) that impact the construction of a single home, each with a different funding source and business model. 

• Each new development is virtually its own company, which is inefficient

• On average 24 subcontractors touch each new single-family home over the year it takes to build, and it’s expensive to coordinate so many people.  

• Multi-family has an even higher number of “subs” and takes closer to 2 years of construction, and over 3-5 years of permiƫting & approvals.

• Coordination also includes surveying and engineering, title work, legal and accounting, distributors, transportation, earthwork, and repairing heavy equipment. 

• There are shortages in the number of contractors and subcontractors, and shortages of workers, and the educational system tends to focus on training employees, not on creating new companies.  

• By some measures, over 40% of total development costs are from increased regulatory burdens over time

• Maine overall has a high percentage (about 30%) of 1 person households, and it’s challenging financially to build for one person households. 

Recommendations for Maine

Here are some of the solutions the author suggests; for a full list see the link to the document below. 

• Establish a repeatable floorplan that could be the basis of a state-wide modular contracted garnering volume pricing and expedited reviews.

• Ask the Real Estate board of appraisers to study valuation methodologies for small homes

• Suspend the finished goods sales tax on modular manufacturing, so that materials aren’t taxed twice. 

• Clarify and train for interaction between code enforcement, factories, and third-party inspectors (TPIs)

• Shift the Manufactured Housing Board to the Maine Office of Community Affairs

• Increase the threshold size of projects that require no additional review

• Shorten approval times 

• Train more students who want to enter the trades

• Create business development programming for tradespeople who want to start their own companies. 

For additional reading and more information the full article can be found at: https://mainehousingcoalition.org/wp-content/uploads/2025/01/Field-Notes-II_Can-construction-technology-improve-affordability-1.7.25.pdf

2023 Live Project Update: An Attached ADU in Portland, Maine

It’s almost been exactly a year and Backyard ADUs is excited to return with a brand new Portland, Maine, live project update! Once again we are keeping this journal entry to update you each step of the way, from feasibility to fruition. This time around we are highlighting a unique project that breaks the mold of what many think of when it comes to reasons for building an ADU. Yes, we often build small homes in backyards for aging parents or children with disabilities or families who want to generate rental income but this time we are building a 400 square foot attached ADU for the homeowners to use as a family room and home office, while also adding a much needed extra bathroom. While it is rare for us to incorporate a loft, in this case, it makes too much sense not to as it will increase usable space while keeping a small footprint. Are you ready? Let’s get started!

June 20, 2023

Many people think they may not have the space to put an ADU in their backyard or add one onto their current home, but you would be surprised at the magic we can make happen. We are starting with a 2-story primary home and a detached garage, along with a large deck and pretty small yard. The plan is to tear down the garage and build the attached space over top of the majority of the garage’s current footprint.

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Site where the new attached ADU will soon stand, after removing the garage.

June 29, 2023

While the garage is being removed, the factory where our house parts are made is busy getting each piece ready to be shipped and delivered. By building indoors in a controlled environment we are able to speed up build time and keep cost down for the homeowner. Just over 3 weeks until delivery day and it is already looking great!

You probably notice how one end differs from the other and that’s because this is the top to our ADU with one side having a vaulted ceiling and the other having the roof lifted on set day to become the loft space.

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One of the house parts that will become the vaulted ceiling and loft after being built in our factory

July 20, 2023

Great news! The garage has been hauled away and we were able to get the excavation done to prepare for delivery and set day next week.

Today the team got started on installing the ICF (insulated concrete forms) so we can pour the frost-protected shallow foundation this weekend, with plenty of time for it to cure for the home’s arrival.

June 21, 2023

The team was able to pour the concrete into the form and the foundation will be cured and ready to be set on in four days.

Both of the house parts also arrived. This will be an easy one for the team due to it being only two parts, one on top of the other. Just two men and our crane team will be able to make this one happen, while others will return to build the breezeway between the ADU and the main home in the days following.

June 25, 2023

Today was originally due to be set day and the team arrived early this morning to receive some unexpected news. When it came time to move the crane into place logistical concerns prevented it from happening today. So while set day is pushed back, we look forward to being able to successfully lift the home into place soon. Stay tuned!

August 3, 2023

Set day is finally here! A smaller crane was brought in and was moved into place, a tight squeeze but went without a hitch. We were then able to move forward with setting this soon-to-be attached addition into the homeowners’ backyard. We also made it happen with only two members of construction team and the members of the crane company!

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Form for the foundation sits where the garage once stood.

One of the house parts sitting next to the newly poured foundation with the sil plates ready to support the home once it is set.

The top house part will be stored off-site until its time to be set.

Now you can see the small space we were working with when trying to fit both the crane and house parts. Great job team!

Our Maine Construction Manager, Don, guides the vaulted ceiling and loft space house part, lining it up with the first box that had already been set on the foundation.

August 17, 2023

In order to attach the addition onto the existing home, the utilities will need to be connected through the basement. Currently, the homeowner is removing some cement board siding, which is necessary to cut the utilities into the basement. Cement board siding may or may not contain asbestos so, for that reason, the homeowner has taken the responsibility to handle this part on their own, cutting significant cost, and at which point we will jump back in to efficiently finish the home.

The addition set next to the primary home, awaiting next steps.

Until our next update, checkout the 2022 Portland live project update HERE.

How "Green" Are Our Homes at Backyard ADUs?

First, let’s look at how we are different from typical home builders.

We Build Small.

Our largest dwelling unit to date has measured in at 1314 sq ft in conditioned space and had 3 bedrooms. The average size dwelling unit in the US in 2022 was 2310 sq ft and has 4 bedrooms. Smaller is better. They use less carbon-intensive materials, use less energy to operate, and are cheaper to build.

We Build Smart

While we are loosely tied to the “tiny home” movement, we do not actually build “tiny homes”. Our homes are designed to have all of the amenities of a large home in a smaller, better-designed footprint. Our homes are designed around the things people do in them, the furniture they have, and don’t rely on size to hide design flaws.

We Build Accessible

Instead of trying to meet the broad requirements of the Americans with Disabilities Act for accessibility in every home, we build our homes to be adaptable to each particular client as their needs change. We create layouts, and accessibility features that will allow our clients to age in place while maintaining affordability and the things they love about their current homes. 

We Build Green (In a realistic way!)

We believe that combating climate change is important, but also understand that money is real. We believe balancing energy efficiency with monetary efficiency is important to actually build green for the largest number of people. If 95% of people can’t afford to build a Passive Haus then Passive Haus is mostly irrelevant.

So in what ways do we build “Green”?

ZeroEnergy Ready & Net Zero

Our standard construction techniques allow us to surpass the stretch energy code requirement by almost 20%. This means our homes cost on average $800 – $1300 per year to run and yes, that includes heating and cooling, and your stove.

This means they can easily be made Net Zero with a roof mounted solar array. The majority of our projects can be made net zero by adding a ~6-8kw photovoltaic (solar) system. In scenarios where there is insufficient sun exposure we may need to build a solar carport to accommodate some of the panels or the homeowner could in invest in community solar.

Above: Solar array being installed on the roof of a carport in order to get peak sun exposure next to the main home in Williamstown, MA.

Maximizing Land Use While Minimizing Land Impact

Utilizing ADUs or multiple small homes on lots provides an opportunity for shared amenities and care that further reduce carbon footprints. Some examples include:

• Sharing a vehicle

• Sharing Garage/Storage Space (1 Garage instead of 2)

• Shared lawn and outdoor recreation equipment 

• Shared Child care (no need to drive to daycare) 

• Shared maintenance cos

Engineered Foundation Systems

We build most of our homes on our “Frost Protected, Shallow Foundation” crawlspaces. If you haven’t read our blog post on their design, you can check it out HERE.

Our frost protected foundation for our 810 SF L-Line uses approximately 16 yards of concrete and approximately 37 sheets of 2” XPS insulation, while a standard 8” thick, 4’ frost wall over a poured footing uses approximately 28 yards of concrete and approximately 42 sheets of 2” XPS insulation 

Less Jobsite Waste

We separate all of our job site waste so that the fewest items possible make it into a landfill and reduce dumpster fees. We sort all cardboard out of the waste pile for recycling and all waste wood into a separate pile. 

Building in a Factory also reduces waste relative to building from the ground up on-site. The factory is climate controlled so materials do not get ruined by weather, material purchases are planned to maximize use across multiple homes, and cuts are planned to maximize material usage by a production engineering team.

Pictured above: components for our homes are built in the factory rather than onsite which minimizes material waste.

Insulating Beyond Code Standard to the Point of Diminishing Return

We focus on energy use per potential occupant. This means we build smaller homes, which require less energy to heat before you even consider how well the homes are insulated.

All of our homes exceed the prescriptive insulation requirements of the most recent International Energy code. Because our homes are small, we don’t need to go too much past this. With fewer SF to heat adding more insulation, making the home higher and using better windows/doors mean we hit a point of “diminishing returns” sooner than a larger home. We insulate our homes to the point where the payback period for doing additional things exceeds 15–20 years.

Our Spes:

Walls:

• R-21, High-density fiberglass (dense blow preferred when available)

• R-9, 1.5” foil-faced Poly Iso OR 2” ZIP system

Ceiling:

• R-60 minimum.

• Flats/cathedrals: loose-blown cellulose (on site)

• Vaults: 12/12 cords with 3” spray foam on the roof deck & 2 R-21 Roxul batts or dense blown cellulose

Foundation:

• Walls: R-22 Nudura Block

• Under-slab: R-10 EPS

Air Sealing:

• 2 ACH50

• 1.5 ACH50 in MA to receive 15k Mass Save Rebate

Above: Image credit given to Personal Excellence. You can read the full article/source further explaining diminishing return HERE.

Air Sealing Beyond Code Standard to the Point of Diminishing Return

We try to reach an air sealing level of 2 ACH 50 in all of our homes and 1.5 ACH 50 in MA where this level is required to receive a 15k rebate. This metric means when the home is depressurized to 50 Pascals, the air within the house only fully changes 2 times every hour. 

In a small home, hitting low-air selling numbers is especially difficult because it is measured as a ratio of air escaping through tiny breaks in the envelope, windows, doors, stove/bathroom fans, etc (numerator) to the total building volume (denominator). Large homes have the luxury of more space/volume to “hide” the air leakage of a door or kitchen stove vent, but we know larger homes use more energy just because they are larger.

Glazing & Windows that Exceed Code Standards to the Point of Diminishing Return

We utilize glazing with a U-factor of 0.26 in all of our homes (15% better than code for overall insulating ability) and utilize glazing with a Solar Heat Gain Coefficient (SHGC) of 0.29 (66% better than code during summer months). The double-hung windows we use have an air infiltration rate of .01cfm/ft2, nearly a tenth of the closest double-hung window you can buy.

No Combustion Appliances

We install only electric appliances. This includes no gas stoves! Induction stove technology has reached parity with gas stoves and is the better option on all fronts.

We Use Heat Pump Technology for Heating & Cooling

We use heat pumps which are up to 400% efficient. Rather than creating thermal energy using electric resistors or burning fuel, heat pumps transfer energy from one location to another. 

There is simply no good reason to heat a home by burning stuff anymore. Don’t forget, if the power goes out a gas/oil burner will not heat your home. These heat systems need electricity to run the air/water circulation pumps and to ignite them. The only true power-outage-proof system is a woodstove.

We Adapt to New Technology

We work hard to not become complacent with how we build and are careful not to reject a new idea, because “this is the way we’ve always done it”.  We constantly seek out other experts and look for more information to improve the energy efficiency of our homes. Most recently this has been appliance technology and initial research into low-voltage lighting.

Get Started Today

If you are ready to get started building your own ADU or small home, the first step is a feasibility study. More information on getting started can be found HERE. In addition, if you have specific questions about the energy efficiency of our homes, please email info@backyardadus.com to get your question answered.

Written by Austin Gregory, Backyard ADUs Chief of Engineering and Operations

Edited & Published by Avril Williams

Our Home Foundations (FPSF) vs. Typical Foundations

At Backyard ADUs, we use a frost-protected, shallow foundation (also known as FPSF) instead of conventional systems to boost energy efficiency, decrease moisture building up, and decrease cost.

History

While we would love to take full credit or the design, these foundations were first used by the well-known American architect, Frank Lloyd Wright, during the Depression to reduce construction costs. The U.S. Department of Housing and Urban Development (HUD) discovered the design and created a design guide in the 90s. The guide helped boost popularity in the southern states, but few builders in New England adopted the frost-protect foundation system over a traditional 4’ frost wall. If you want to dive further into FPSFs, the guide has since been revised and can be accessed HERE.

Typical Frost Wall Foundation

There are generally four different foundation types used in New England. Traditional foundations are 4 –9 feet tall and have a base at least 4’ below the surface to protect against frost. These foundations also sit on a separate concrete footing. They are insulated on one side of the wall and usually take around 2 weeks to construct.

Our Frost Protected, Shallow Foundations (FPSF)

A FPSF is only 18 inches tall, wich provide just enough room to create a fully conditioned crawlspace for utility access. Builders frost protect the foundation with a wing of rigid foam insulation (XPS) that extends beyond the foundation perimeter to lift the frost line up around the home. When scheduled well, a building can complete this foundation in 2 days.

How are they similar?

• Both techniques have a perforated drain pipe around their bases which are covered with 3/4” stone and a filter fabric. This drains water away from the foundation of the home, helps keep the basement dry and prevent unseen erosion. Water either drains to “daylight” down hill from the house or into a drywell that allows water to percolate back into the soil.

• Spray foam is used where the foundation and the home meet. This provides insulation and creates an airseal, improving energy efficiency.

• Rebar is used to strengthen the concrete and prevent foundation failures.

• Both have a layer of insulation board (XPS) underneath the floor.

• Both attach the home to the foundation using a sill plate that is bolted to the concrete

Above: XPS insulation board laid over screeded sand used to level the site,.

Above: Inside of the ICF blocks. Rebar sits on top of the black brackets.

Why We Choose to Use FPSF

TIME

Two days instead of 2 weeks! The FPSF only requires 1 concrete pour and 1 inspection, whereas a traditional foundation requires 2 of each. By doubling this, the process moves from just a few days to a few weeks due to coordinating schedules of all of the people involved and the potential for weather delays.

MONEY

Creating a taller foundation also requires MUCH more concrete and labor. In fact, the traditional 4’ frost wall foundation takes more than twice as much of each, which can easily double the cost.

These shallow crawlspaces also make the house more efficient. They are much smaller spaces, and hence, minimize heat loss potential.

HEALTH & SAFETY

The shallow crawlspace is passively conditioned by the heating and cooling of the main house. This improves air quality by preventing moisture and stale air that lingers in so many basements and crawl spaces.

ACCESSIBILITY

We create a water-tight seal between our continuous wall insulation board and our insulated concrete forms which allows us to bring our floor system 4” from the ground instead of 8”. This enables us to have just 1 step into the house instead of 2.

This sounds like a small improvement, but that 1 additional step means landings, railings, and an extra 8’ of ramp length if a ramp was ever needed.

THE BIG ONE: RISK FACTOR

Our FPSF dramatically reduces your risk factor! What does that mean? The number of unknowns and chances for unexpected events increases you dig deeper to accommodate a crawl space. Those unknowns include solid rock, huge boulders, high water tables, underground springs, or even an ancient sacred burial ground. Each of these events adds unexpected cost and cause schedule delays.

Above: Traditional and ICF Foundation details.

What about the frost line?

A 4 foot foundation is 4’ tall so the footing will be below the frost line. Frost generally does not extend deeper than 4 feet in the area we build. When frost goes underneath a foundation it can push the foundation up (think of frost heaves in the road). A frost heave under your home can cause an incredible amount of damage as the ground shifts and moves parts of your home while others stay still.

Our FPSF is frost protected with insulation (instead of digging below it). Our foundations have a wing of 2” XPS rigid foam board that extends out beyond the perimeter of the home. This prevents cold temperatures from freezing the ground adjacent to or under the foundation. The foam extension allows the ground under the foundation and crawl space to remain at a stable 50-55 degrees Fahrenheit year-round.

Will it blow away?

No, it will not blow away. The concrete for our L-line’s foundation weighs about 34,000 pounds which provides a substantial anchor to keep the house on the ground.

Above: A shallow frost-protected foundation ready for a home to place on it.

Have more questions about our homes? Go to our FAQ page to get them answered and if you can’t find the answer there, feel free to email info@backyardadus.com and someone will respond with the information you need. Otherwise, the first step to get started building is by signing up for a feasibility study to see what’s possible.

2022 Live Project Update: Backyard Home (ADU) in Portland, Maine

Backyard ADUs has a new small home project in Portland, Maine and we are keeping this journal entry to update you each step of the way. We are building for the homeowner’s mother and the ADU will be a detached 700 square foot backyard home that utilizes our square design path. One of its unique features is a beautiful, covered porch with a large bay window. In addition, if all goes as planned, it will be our fastest build from breaking ground to move in. Let’s get started!

July 30, 2022

The team has already been on site to mark off the exact location that the home will be (marked with wooden stakes shown in the photo). We brought in an excavator a few days ago to start the work today when we finally, after a huge permitting headache from the city, broke ground! The swing set was moved from it’s current location to make room for the home and create a safer space to play, and the hole that will become the foundation was dug.

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Portland build site ready for digging

August 1, 2022

The construction team came in today and started framing out the foam foundation. They fully completed the frame with our highly-efficient foundation framing strategy, including checking the grade to assure everything is level, making it possible to start pouring concrete tomorrow.

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Checking the grade to be sure the new foundation frame is level for tomorrow’s concrete pour.

August 2, 2022

It was nearly 90 degrees today but what a productive afternoon! Two mixers of concrete showed up around 2pm and we immediately got started pouring. Concrete was flowing perfectly and the entire project was completed without a hitch…well, aside from accidentally stepping in a hole full of concrete, filling his boot. :) We then leveled the base using a 2x4 and it was left to setup, making it ready to go for next week’s set day.

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Team finishes pouring the floor of the foundation after having filled the walls.

August 11, 2022

The stone and base of what will become the front porch is in. The area around the home has also been leveled and hay laid to keep dust to a minimum and keep grass seed in place after the set when landscaping is done. Today the team started laying the wood on which the house will be placed and installing center support beams where the two boxes will meet. Just about ready for next week’s Set Day!

Site is almost ready for Set Day next week. Foundation support installed and preparation for the porch installation is complete.

August 15, 2022

SET DAY IS HERE!! Just over two weeks since breaking ground and today we brought in the two boxes that will make up the 700 sq ft square design path home. It was a tight squeeze getting them in but with just inches to spare, they made it! Many people are surprised to know that the boxes, which are pre-built off site, come with many of the details already installed such as tile, cabinets, and fixtures, shortening the time it takes to be move-in ready. Within six hours, what was just a foundation and some gravel became a house complete with a porch and finished roof. The team will be continuing to work on this project, including completing the siding, painting, flooring, and installing utilities, over the course of the next couple weeks.

Tight squeeze moving the boxes into the backyard

One box complete. One more to go!

One side of the roof goes up.

Roof and insulation are finished just in time to wrap up the day.

August 23, 2022

The team worked hard yesterday to get all of the ceilings painted, the deck complete and a good start on the siding. The siding is Midnight Blue by Certainteed and is one of, if not the, most popular siding color chosen by our clients. You might also notice that the bay window, which will add an incredible amount of light to the living space, was installed a few days ago.

August 31, 2022

Wow! The siding is fully complete and utilities are being hooked up as we speak. All of our homes are net zero ready. While this one doesn’t currently have solar panels, it is ready to go if that choice is made in the future, completely eliminating an electric bill. With the exterior almost finished we can now start giving some extra love to the inside. The homeowner has chosen custom finishes such as light fixtures and some bright paint colors. We can’t wait to see how they look!

September 12, 2022

Our homeowner used to live in a very dark space with minimal sunlight so now she’s making up for it because nothing about this house says dark! Statement light fixtures have been installed in every space that only add to the already present windows, allowing lots of light both day and night. To top it off, she has chosen some fun, bright wall colors that pop. The hood has been added above the stove and we hope to have this project completed by the end of the week. Stay tuned for the grand finale!

September 20, 2022

Our first Portland live project update home is complete and ready for the homeowner’s mom to move in! Be sure to subscribe below to see the next home building project process that we document.

Live project update: Backyard Home (ADU) in Carrabassett Valley, ME

Based on Backyard ADU Live Video on November 7, 2020.

If you would like to see the original video you can do so to the right.

Here at Backyard ADUs we are doing a really cool project in Carrabassett Valley, Maine. It’s our first ski/vacation cabin project and it’s located just below the access road to Sugarloaf Ski and Summer Resort.

At the time of this writing we’re currently in the process of evaluating two very small pieces of land that each have one existing cabin on them, right on Carrabassett stream.

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Snapshot from FB Live: Two existing cabins

This is a really great opportunity to pick up two very small pieces of land, both very close to Sugarloaf, where you can walk right onto a pathway for mountain biking, skiing, walking and hiking up the mountains. We'll install decks right out on the Carrabassett stream, which is going to be very neat.

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Snapshot from FB Live: Carrabassett Stream

We are seeking planning board approval to replace each existing structure with one of our BADU homes. We are going to try to recycle the old structures and move them to a different location so they can continue to be used. We'll be putting in two new, small, super well-insulated, 450 square foot cabins with sleeping lofts. We're hoping they’ll be ready for the 2021-2022 ski season. We expect to start construction this April or May. For 2021, the old structures will be somewhat usable, but will probably stay vacant until they can be renovated.

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Snapshot from FB Live: Old cabin on Carrabassett Stream

We are so excited about this project! If you've ever thought about trying to put a cabin up in the woods or on a lake then stay tuned to see more about what we're doing up here in Carrabassett Valley in beautiful Maine.

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Snapshot from FB Live: Old cabin on Carrabassett Stream.

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Snapshot from FB Live: Old cabin on Carrabassett Stream

Live project update: Backyard Home (ADU) in Whately, MA

Transcript from Facebook Live Video on November 11, 2020

If you would like to see the original video you can do so to the right.

Chris:
Hey everybody, Chris Lee here, with backyard ADUs. I am onsite in Whately, Massachusetts, where we are building yet another backyard home. In this case, the ADU is again for a family. The homeowners are building an extra space, for his brother.

The really neat thing about this one is we're poolside and I will show you, we are building the house is right here. We're putting in the insulated concrete forms, but over that fence, you can see the pool. This project is really neat because we're framing in that back pool area. We're creating a little deck with French doors that will open up onto it. It's really going to transform this backyard space. At the same time, it will give the homeowner's brother a place to live.

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Snapshot from FB Live: ICF foundation & Rebar, Poolside

As part of the project, we replaced all the siding on the main house to make sure the house matched the new small house that we're building. We're also building a 27' x 27' garage which will expand parking space and give the homeowner a place to work on motorcycles and to store his tractor. Here is what Kevin Schnell, head of the project and Head of General Contractors at Backyard ADUs, had to say on the project.

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Snapshot from FB Live: Main house new siding going up.

Kevin Schnell:

We're starting to set our dura ICF block.

Chris Lee:

That's the Lego looking stuff?

Kevin Schnell:

Yes, it's an insulated concrete form, 8” of foundation inside the form and 1.5” of a foam on each side. We do a 20” wide footing, 1’ tall, which puts us around 9” above grade. Hopefully by the end of the day, we'll have all of our blocks set, this takes us about two hours to set a foundation this size with blocks like these, and then we'll move and set all of our blocks for the 27’ x 27’ garage.

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Snapshot from FB Live: Dura ICF block installation.

Chris Lee:

How long does it take to form and pour a traditional foundation?

Kevin Schnell:

Typically a standard foundation wall with a casting plate, would mean you have a crew come in, set your forms in a day. Then you'd have to pour it another day, then you'd have to strip and forms which would be another half day. However, with this we'll have this ready by around one o'clock today and then we'll start setting our blocks for our garage. My goal is we'll be able to pour both of them Thursday or Friday dependent on weather, which really makes it quite fast in comparison. This house will be ready to be set mid January.

Chris Lee:

Thank you.

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Snapshot from FB Live: Dura ICF block installation.

Chris Lee:

That was Kevin Schnell, Head of General Contracting for Backyard ADUs overseeing all the work here in Western Mass and increasingly throughout the state. As Kevin said, they're putting in the insulated concrete forms here in Whately, MA both on our poolside Backyard Small Home and for the garage. Stay tuned there'll be more updates Coming soon.

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Snapshot from FB Live: Dura ICF block installation close up.

Planning Your Backyard Project (Video)

Learn how we planned our backyard home (ADU) project in Easthampton, Ma

This video walks through the planning process that we used for our project in Easthampton step by step. The video is specific to the Easthampton home, but the information will help point you in the right direction for your project.

The video explains how we:

• Replaced the water service line (and why)

• Connected water and sewer

• Evaluated the existing electric service

• Added a new electric and cable service

• Found the property lines

• Measured setbacks

• Decided where to place the home

• Parking requirements

How to Plan Your Backyard Home (ADU) Project

How to Plan Your Backyard Tiny Home Project:

First, let us define what we mean by “backyard tiny home” because we are not talking about “tiny homes on wheels” that don’t come with a plan for last night’s dinner...

What’s the difference between this two tiny homes?

This could be a legal backyard home.

The difference goes beyond the visible wheels.

A backyard tiny home is a residential building code compliant structure often referred to as an Accessory Dwelling Unit (ADU), granny flat, backyard cottage, micro-cottage or even a casita in Southern California. The homes are typically smaller than the existing “big” home on the property, making them relatively tiny. Often they can be up to 900 SF, much bigger than the ~150SF homes seen on Tiny House Nation. 

However, the biggest difference between what we build and the image you may have in your mind is that a backyard home must home comply with state building codes.  This means it’s secured to a foundation, connected to utilities (sewer, water, electric), and is thoroughly insulated like a normal, standard house. (And, in fact, with the ADUs we build, it will probably be much better insulated than your current home.)

Interestingly, this does not mean that it can’t also be street legal. This will be the subject of another post. 

Ok – Moving on to the purpose of this article. How does a homeowner plan and then build a backyard tiny home in New England?

Step One: How will you use the backyard tiny home?

Nobody starts a project like this without a good reason for doing it. I (Chris Lee) have been blown away by the number of different ways homeowners are planning to use a backyard home. Here are a few of the more common uses:

Aging Parents: 

The biggest increase in renters and single-member households are seniors, who are also known as somebody’s grandparents. These grandparents are using new zoning bylaws to build a separate home (aka, “detached ADU”) on their children’s properties to save money and be closer to their family. Until recently most of these dwelling units had to be attached to the existing home. That has changed, which makes this option more palatable. We’ve heard families call these homes close, but not too close. 

Parents Helping Adult Children: 

Given the high cost of housing, construction, and land many children cannot afford to live in the communities in which they grew up. Aging parents have begun downsizing into their backyards and selling their old “big” house to their children.

Caring For People With Disabilities: 

There is a huge population of adults with a disability that could live independently if they stayed close to family. A backyard home creates the opportunity to give these persons their own space, the dignity of their own front door and keep their family close enough to provide love and care. 

Veterans Housing Veterans: 

There is an ENORMOUS opportunity to house pair Veteran homeowners with Veterans that are either homeless or having trouble finding a safe, comfortable place to live. Beyond housing, this approach to providing Veteran housing would create opportunities for mentorship and help Veterans integrate back into their communities. 

Full-Time Office & Part-Time Guest House: 

For those of us that work from home a backyard home can act as an office and guest house. When family or friends come to visit the office can be set up as a guest house. In most towns, it can even be used for Short Term Rentals, which create the opportunity to completely offset the cost of the space.

As a Rental Unit: 

We are in a housing crisis and every backyard has the potential to help alleviate it and generate income for the property owner. Backyard homes can be built to rent to tenants and often produce a CAP rate over 10, which is virtually unheard of in today’s real residential estate market without excessive risk. If the homeowner is willing to rent the home to someone with a disability or senior, they may be eligible for $50,000 at 0% interest that does not need to be repaid until the home is sold.

Step Two: What Can You Build?

Homeowners should determine what they can build on their property before worrying too much about the cost and how to finance construction. 

It is tempting for people to simply call their local planning department and ask “How can I build a backyard home?” 

But it will serve you a great deal more to do some research on your own first, including taking a look at your town’s ADU regulations. This will allow you to prepare more specific questions and help you get the most out of your local planners’ expertise. Some examples of questions you might have are:

• Could you show me where I can get more information about the rules for building an accessory dwelling unit on my property?

• Just to confirm, if my ADU is <20’ tall can it still be placed directly on a side lot line?

There is also an enormous amount of information on our website (https://backyardadus.com), including links to the ADU rules of many towns. Read on to see an overview!

Free Resources provided by Backyard ADUs:

We (Backyard ADUs) have spent countless days aggregating and converting local zoning bylaws into plain English to help homeowners begin their process. You can look for your city here, and if we haven’t created a page for your town yet let us know!  

We have also created D.I.Y. property evaluation guides that will walk you step by step on how to determine what you can build. Our team actually uses these guides when we create our custom property reports. 

If you want to dig into your town zoning bylaw independently, here is what to look for:

The ADU bylaw 

Towns in New England will title their ADU section as “Accessory Apartments,” “Supplemental Apartments,” and “Accessory Dwelling Units”. When reviewing this section you must confirm whether a “detached” ADU is allowed, review the restrictions, and what the permitting process consists of. 

Set Backs

Each zoning bylaw has a section that defines how close a structure can be built to neighbors. Set back requirements are different per zoning district and can be found in separate tables often called “Area Regulations,” or  “Dimensional Regulations.” 

Accessory Structures

If a detached ADU is considered an accessory structure, you must review the rules for accessory structures in your town. These can include special set back rules, height restrictions, design requirements, and privacy barriers.

Parking Design:

If the ADU bylaw requires parking to be provided you will need to find the bylaw’s parking section. The zoning bylaw will define exactly how big a parking spot needs to be, where it can be located, and what materials can be used to build it. 

Open Space Requirements: 

Town zoning ordinances often define the maximum amount of ground that can be covered by structures. Zoning bylaws most commonly refer to this as “Building Coverage Ratios” or “Open Space Ratios.”

Environmental:

Environmental is probably the most difficult part to understand as the rules have some ambiguity and leave room for flexibility. The biggest items homes owners will see are related to restrictions on removing trees, drainage, and runoff. 

Step Three: Ballpark Construction Estimate

Once you know what you can build it’s time to get a ballpark number on construction cost. Unfortunately, a ballpark number is really difficult to get from a General Contractor. They don’t like providing these types of estimates for fear of being held to them later on and they simply don’t have time!  

When you do get in touch with a GC you will want to sound very confident about doing your project and your ability to pay for it. If you don’t, they will think you are “window shopping” and will not allocate the time to producing a quote. Additionally, don’t be afraid to follow up about the quote once per week until you have it. 

Backyard ADU provides fixed prices for our ready-to-build homes, with our standard specs on typical lots to save you time. Check Backyard ADUs prices.  

Step Four: Financing Options

First off– financing should not be a reason not to do a backyard home project. I (Chris Lee) have a background in Real Estate Financing and there are so many creative strategies to paying for a backyard home. I have also been blown away by how many publicly funded options are available in Massachusetts to help people with disabilities and seniors age in place.

Cash:

If you are consolidating households the proceeds from a home sale can be used to fund the construction of the new home. 

Massachusetts’ Home Loan Modification Program: 

$50,000 at 0% interest with no repayment due until the home is sold. This funding is available to help modify a home (building a backyard home counts) for people with disabilities or to help seniors age in place. An accessible backyard home does count as a modification. 

See state website

Reverse Mortgage: 

This option is available for seniors. It can be an extremely attractive option for cash strapped seniors that are trying to downsize. Funds from a reverse mortgage can be used to construct the backyard home, after which, the senior could rent out or even sell their old primary home to generate much-needed cash flow.

FHA “Home Style Renovation” Loan: 

This is a construction loan that allows homeowners without excellent credit to do renovations on their properties and still get 30-year financings and the low-interest rates associated with mortgages. 

Cash-Out Refinancing:

This is a traditional mortgage refinancing where the homeowner takes out a new mortgage on their home, resets the payment schedule and withdraws cash from their home’s equity. Depending on how much equity is in your home, your current interest and original loan balance, you could withdraw a significant amount of money without changing the mortgage payment. 

Home Equity Line Of Credit:

This is a line of credit secured by your house to keep the interest rate more affordable. This option has a higher interest rate than home refinancing and shouldn’t be used to pay for the entire backyard home project.

Self Directed IRA: 

An IRA can be used to invest in real estate. By setting up a self-directed IRA, a homeowner could potentially use funds from their IRA to build an ADU as an investment property. This option is somewhat experimental as it is a brand new concept and requires a third-party custodian to keep careful documentation about rental income and expense.  

Step Five: Permitting & a trip to the Town Hall

If your town allows backyard homes by right (Northampton, Great Barrington, Montague, Plainfield and much of Cape Cod), your general contract just needs to pull a building permit as if an addition was being constructed. 

If your town requires a special permit to build an ADU expect 2-4 months of waiting and a public hearing to review your application. This step usually sucks and can take months. It can be intense and challenging. It will be important to prepare extensively for this type of hearing and it is extremely helpful to communicate with your neighbors to gauge opinions and prevent unnecessary angst during the meeting which can cause delays. 

Step Six: Construction

Finally, with a  permit in hand, you can build. Depending on what construction methodology you chose, active construction could last anywhere from 2 weeks to 2 months with modular construction being on the shorter time frame.

Want someone else to do all the work?

In case you were wondering, Backyard ADUs is able to help homeowners beginning right at step one in this process. Getting a backyard home planned, approved, and built can be a daunting DIY project. At Backyard ADUs we love to help you get started early on, and can, of course, see you all the way through to completion.