Editorial Feature

Building Materials Suitable for Cold Conditions

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Oct 28 2016

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Frozen pipes, burst pipes, drafty rooms, and high heating bills are all major concerns for people living and working in cold weather conditions.

From the foundation to the roof, various building materials have been designed to prevent or reduce these problems. In an effort to better combat these problems caused by the cold, researchers are constantly investigating novel and innovative building materials.

Foundation Materials

During extremely cold weather conditions, the foundation of buildings can be a primary cause of heat loss that can also be affected by surrounding soil conditions. Good drainage and foundation waterproofing are crucial components that can prevent cold weather problems.

If surface moisture is not handled properly from the beginning, it can become an expensive hassle later on. Surface moisture can arise from exterior sources, such as rain, humid air or ground-water, or interior sources, such as humidifiers, unvented washing and/or drying machines, and bathrooms¹. One way to prevent surface moisture early on is through the installation of a mitigation system, which typically consists of many of perforated pipes that are placed in specific locations beneath the slab that connects and stubs out of the slab at an exhaust point.

A second way to prevent surface moisture is by eliminating low spots that surround the building’s foundation. If these low spots cannot be removed, cleaning these areas at least twice a year and performing a hose test can also improve the foundation’s ability to resist unwanted moisture from entering the building².

Ground temperatures are invariably colder than those indoors during cold weather, so there will be some degree of heat loss. The amount of heat loss depends on the outside temperature, soil temperature, and the quantity and quality of insulation in place.

To determine what insulation foam is most appropriate for your specific building project, the r-value is a useful parameter that represents the resistance of the insulation foam board to heat flow. The higher the r-value signifies a greater insulation power of the material; therefore, long-term buildings typically require insulation materials of a higher r-value.

Gaining in popularity, insulated concrete forms (ICF) are hollow foam blocks comprised of both expanded polystyrene (EPS) and steel-reinforced concrete that are stacked into the shape of the exterior walls of a building. Typically reinforced with steel rebar and filled with concrete, ICFs are then covered with brick, stucco, rock or siding, depending upon the specific building requirements³.

Although ICFs are more expensive as compared to other types of materials, such as plywood that averages at $1.55 USD per square foot, whereas ICF averages at $4.10 USD⁴, ICFs offer substantial labor savings, as many can be put together in a few days, thereby resulting in shorter construction time.

Additionally, an ICF home is estimated to save a homeowner 30-70% in energy consumption and costs, which is advantageous for both the consumer and the environment.

UK Company Polysteel has developed the Warmerwall range, which is a range of ICF blocks that can be used for building foundations. Manufactured using building grade flame retardant polystyrene, the Warmerwall blocks lock together to form walls and foundations, into which a specialist concrete mix is poured. Due to the high level of insulation provided by these ICFs, a significant reduction in heating costs can be achieved, thereby making this technology an ideal tool for cold temperatures.

Exterior Walls

The three biggest concerns when it comes to walls in cold weather are air, moisture, and heat loss. Most cold weather construction effectively combats these concerns through the use of double walls, which involves building two stud walls; one that is load-bearing and a second wall that is not. The load-bearing wall is generally sheathed in plywood to permit insulation to be installed from one side, whereas the double-wall system still includes components of a standard wall-like structural sheathing and house wrap.

The space between the two walls is then filled with insulation, which can include materials such as blown-in cellulose, blown-in fiberglass or fiberglass batts, all of which are recommended materials by the Cold Climate Housing Research Center in Alaska.

Blown-in insulation is common, as this type of insulation material effectively fills in all of the spaces present in the double-wall system, such as the voids that are present between inner and outer wall studs, blocking and corners. Both cellulose and fiberglass blown-in insulation materials are sold in compressed bales that are inserted into a blowing machine, which is then used to chop up the bales and pump insulation into the wall through a hose and a blower.

Devana Insulation in Cambridge has developed Warmcel cellulose fiber insulation, which is a high-quality natural material that is made from recycled newspaper that has been shredded. Devana also incorporates natural inorganic salts to the shredded paper to provide added resistance of the fiber against fire, mold, insects, and vermin.

Through cellulose blown-in insulation procedures, the flow of air slows down, thereby decreasing the amount of heat that may be lost from a property. Additionally, Warmcel cellulose fiber also retains heat more effectively as compared to other materials, making this material ideal for cold weather conditions. Cellulose is non-flammable and has an R-30 rating at 8.1 inches of thickness, making it the most efficient material in retaining heat.

Regardless of whether blown-in insulation is conducted indoors or outdoors, it must be a contained procedure. Insulation blown in from the outside of the structure can be held in place by house wrap and furring strips, whereas insulation blown in from the inside can be held by a fiber mesh affixed to the studs.

In both cases, openings are cut in the membranes to allow a hose from the blower to be inserted to pump insulation. If the double walls are significantly far apart from each other, the insulation may also be blown in from the top, which minimizes or completely removes the need to cut access openings.

Walls that are built to withstand significant cold conditions also include a vapor retarder to prevent interior moisture from escaping. This protective layer is normally a 6 mm polyethylene sheeting that is placed on the interior side of the wall system.

Roofs

Slick roofs and sloped metal can cause ice and snow buildup to slide and hit building elements or areas under a roof or wall, both of which can pose a real danger to surrounding people and property.

Although no specific standards have been developed by governmental agencies, such as the U.S. Occupational Safety and Health Administration (OSHA), it is recommended that individuals who are working or living near low- or steep-slope roofs are aware of the potential hazard of falling snow and ice during the design phase.

Vegetative and cool roof construction are viable methods that have been suggested for their ability to combat cold weather issues. A vegetative roof, which combines several thin layers of living vegetation above a conventional flat or sloping roof, can add roughness and intricate geometries that can minimize slide by absorbing rainwater runoff and provide insulation.

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However, it is important to note that these assemblies are often heavier, which can potentially increase the volume of snow collection on the roof and ultimately lead to large snowdrifts in tricky locations. The build-up of soil and vegetation on this type of roof can pose challenges with the meltwater drainage path and create hazardous localized loads.

Cool roof construction, which is normally comprised of higher insulation values coupled with light-colored roofing materials, has a noteworthy influence on the rate of snowmelt. While raised insulation decreases potential heat loss from the building's interior, light-colored materials decrease solar absorbance.

The combination of these two mechanisms can have varying influence on the amount of meltwater present within an accrued snowpack, as this factor is ultimately based on the selected exterior weather conditions.

However, cool roof construction can also reduce the rate of snowmelt. Thereby causing the roof to be more vulnerable to deeper snow, ice, and icicle formations. This has ramifications to snow load suppositions, localized loading because of melt and re-freeze, as well as the formation of bigger ice masses beneath deep snow formations that can lead to sliding ice and snow and/or roof destruction due to expansion.