he same advice for dressing in cold climates applies to structures as well: layering. Contractors apply control layers to the building envelope—the shell of a building that protects occupants from the elements—to manage the water, air, vapor, and temperature within a structure. This complex layering system within the foundation, roof, walls, windows, and doors that make up the building envelope isn’t obvious to the untrained eye. However, professional testing will quickly reveal the effectiveness of the control layers that make up the building envelope.

A structure with effective control layers is both durable and comfortable. In general, it has a water-resistive barrier outside of the framing to keep water from getting into the walls, is airtight for energy efficiency, prevents condensation in the walls, and has the right type of insulated walls. Creating this kind of balance in a cold-climate building wasn’t always the priority of contractors in Alaska. Dave Harrell, owner of Northern Home Consulting and former owner of Cold Climate Construction, says there was a big push in the ‘80s and ‘90s to make buildings airtight in the name of energy efficiency. However, it wasn’t long before buildings started having problems with decay, mold, radon, and other issues. Harrell says contractors quickly found that sucking out the wet, stale air with an exhaust fan often led to backdrafting, pulling carbon monoxide from heating appliances into the living space and making people sick.

“We learned that the best practice is to have sealed combustion heating appliances and adequate balanced ventilation, such as with a heat recovery ventilation system,” says Harrell. “Builders adopted the adage ‘build it tight and vent it right.'”

Harrell considers moisture management to be one of the biggest challenges of designing and constructing cold-climate structures. He says moisture management is more than just the precipitation on the exterior of the building and the vapor from underneath but also the management of the moisture produced by those inhabiting the building doing daily activities such as cooking, washing, and simply breathing. Properly ventilating a building requires contractors to consider the entire design and specifications—and to be willing to ask for help when they don’t know the answer.

Workers weatherize the Lakeview Lodge in Minto.

Russell Snyder | Interior Regional Housing Authority | US Department of Energy

Of all the materials in the control layers, insulation often gets the most attention. Over the years, manufacturers have developed a range of insulation types with R-values, which measure the insulation’s ability to resist heat traveling through it, ranging from R10 to R60. The higher the R-value, the better the thermal performance of the insulation. That doesn’t mean that R60 is the automatic choice for a structure. Structures can have insulation with different R-values throughout, depending on the need for temperature control. Added to this are the multiple insulation materials. Though fiberglass is one of the most common insulation materials, there are other options including cellulose mineral wool, polyurethane foam, and polystyrene.

In Alaska, Insulfoam manufactures expanded polystyrene (EPS) rigid foam insulation in Anchorage for distribution in building supply locations statewide. Stu Laidlaw, territory manager for Insulfoam Alaska, says EPS offers many benefits over other insulation types. As a rigid foam, EPS doesn’t suffer the disadvantages of spray foam insulation, including the potential for air bubbles to form during the installation process, which reduces the R-value, or material shrinkage that comes with aging and constant exposure to temperature changes. Compared to other rigid foams, Laidlaw says Insulfoam’s manufacturing process ensures that the R-value of their products remains the same over time.
“Blowing agents used in our competitor’s products create a scenario where off gassing results in an R-value decrease over time,” says Laidlaw. “We don’t have that problem. Our products retain the same R-values as the day they were installed.”

In addition to being a highly customizable product that is durable and weather resistant, Laidlaw says Insulfoam products are readily available. Since they’re manufactured within the state, distributors don’t have additional shipping costs that come with products originating in the Lower 48. This results in significant cost savings and the highest R-value per dollar compared to competing rigid insulation like XPS (extruded polystyrene) and polyisocyanurate. Due to foresight and careful planning, Laidlaw says Insulfoam managed to avoid supply chain disruptions with raw materials, meaning that they’ve been able to continue manufacturing products at a steady pace.

“The supply chain issues in Alaska are very real,” says Laidlaw. “We anticipated the situation and didn’t skip a beat getting our product to market at a price Alaskans can afford.”

Harrell says contractors have to take the cost and availability of building materials into account more than before COVID-19. He says during the pandemic many builders had to try new products and adjust their methods because familiar materials weren’t always accessible.

“There are plenty of good materials that will fail after a short while if installed incorrectly,” says Harrell.

Harrell has seen this problem firsthand as a contractor and through his consulting firm in Talkeetna. He says the majority of Alaska doesn’t have rules or regulations for building construction, and without a statewide building code, he finds a lot of Alaskans strike out to the rural areas and build their dream home or cabin without rules or interference. Unfortunately, many of these Alaskans get in over their heads with disastrous results, and often they turn around and sell their home or cabin to someone who has no idea what they are walking into.

“Alaska is a fiercely independent place. So many of us want to do it ourselves and be stubbornly self-reliant,” says Harrell. “I’m all for freedom and liberty, but I’ve seen this situation play out time and time again. When our government can’t enforce rules and codes, which is hard at times, then we need to at least provide resources, education, and incentives so our housing stock isn’t made up of falling down, rotting, dangerous homes.”

Harrell recommends people check out the resources available on the Alaska Housing Finance Corporation and Cold Climate Housing Research Center (CCHRC) websites, two organizations taking the lead in providing information and research into new cold climate technologies and methodologies. Though he thinks the technology and methodology for retrofitting existing homes is improving, there’s less work to weatherproof a home during the initial construction phases. When it comes to remodeling and renovating homes for cold climates, Harrell says people most likely will not get everything they want, since some ideas are not practical or cost effective.

Cold-climate construction is constantly evolving, though people may not see the results of that innovation right away. Benjamin Callahan, president of Callahan Construction Company in North Pole, says many times initial innovations happen either on the job site or at the engineering level.

“It takes a few years and some real-world examples before we start to see the newer ideas incorporated into state or federal projects,” says Callahan. “I think the acceptance of new concepts and ideas are more frequent now than twenty years ago. Energy conservation is on everybody’s radar.”

With finite resources, Callahan says contractors need to build structures that will still serve the needs of future generations. Likewise, Harrell says the need for buildings will always be a crucial part of human existence, so it makes sense to construct safe, healthy, long-lasting buildings. Harrell says there is a growing trend for high performance homes designed to be Net Zero, where the energy a home consumes equals the energy it can generate. In 2022, Harrell pulled together his previous experience as a contractor and energy rater to help build a Net Zero home using a ground source heat pump and a large roof-mounted solar panel array. His company is currently collecting data to see if they have met their Net Zero goal.

“We don’t want to waste money and resources on creating buildings that won’t last,” says Harrell. “It’s not just an environmental issue or a monetary issue. It’s a social issue.”

Harrell says one of the most significant recent innovations came from CCHRC when it started pushing the REMOTE (Residential Exterior Membrane Outside insulation TEchnique) wall system. CCHRC—a laboratory in Fairbanks established by the building industry in 1999—adapted the PERSIST (Pressure Equalized Rain Screen Insulated Structure Technique) wall technique used in northern Canada to form the REMOTE wall, which moves most of the insulation to the outside of the wall to keep the sheathing warm and dry. The vapor barrier is applied outside of the sheathing, rather than inside, and then foam board is attached to the vapor barrier. The key is to use enough foam so that two-thirds of the total wall R-value is located on the outside. The goal is to keep the point at which vapor turns to water (the dew point) outside the vapor barrier and warm-side wall cavities. This ensures the framing stays warm and dry. CCHRC has tested and refined the REMOTE wall in various climates of Alaska, and includes resources, a detailed construction manual, and a two-part video showing the step-by-step process of building a REMOTE wall on their website.

“The REMOTE wall system really got people to recognize that thermal bridging, the heat transfer through materials, was important and airtightness could be significantly improved,” says Harrell.

CCHRC features several videos, construction manuals, and step-by-step instructions for both new construction projects and retrofits that meet cold-climate construction specs. They also have additional information about alternative energy sources and current building science research in Alaska.

Callahan cautions that there is no single method of building a cold-climate structure in Alaska. Techniques and materials are not necessarily the same as in other places that experience subzero temperatures, and he adds that environmental factors vary across the vastness of the state, affecting the combination of building materials and how they’re installed.

“Building in Fairbanks is different than Anchorage,” says Callahan. “Building in Fort Greely is different than Fairbanks. You must have experience, but also be willing to try new ideas.”