By: Terry Meier, Architectural Sales Representative
A few years ago I decided to go skiing on what was a very cold January day. When I arrived at the ski resort I realized that I had all of my warm clothing (hat, coat, pants, socks etc). I had everything that I needed, everything that is except one thing, GLOVES! Without gloves I was unprepared for the harsh weather conditions that day. It seems like a small thing, but cold hands make for a miserable skiing experience.
I think that insulating a building is similar to dressing to stay warm. If we forget just one area a big difference is noticed, even if we remembered everything else.
Many times the insulation around the perimeter foundation and slab is omitted and yet up to 50% of the buildings total heat loss occurs at the perimeter and slab of the foundation. Below-grade insulation is crucial to achieve energy-efficiency and to some degree a comfortable interior climate.
If the slab and foundation wall isn’t insulated there will be a thermal bridge allowing a large amount of heat transfer out of the building.
In cooler climates the temperature of the slab perimeter may be below the dew point of interior air. Even when condensation conditions are not present on the slab surface, relatively cool temperatures near an un-insulated slab edge will tend to elevate the local relative humidity. As the humidity rises so too do the risks associated with mildew, mold, fungal growth, dust mites and other pests.
Adding Below-Grade EPS insulation outside of the slab edge will allow the inside surface temperature of the slab perimeter to more closely track interior conditions thereby reducing the potential for condensation and elevated humidity.
Be aware that perimeter insulation can give burrowing insects, (such as termites), access, so be sure to provide a barrier. This can be accomplished by using EPS foam treated with PERFORM GUARD. Perform Guard has been thoroughly tested and uses a safe natural mineral that is formulated to resist insects. The treatment is effective and lasts as long as the product.
In addition to its insulating properties, using EPS foam around the perimeter foundation and slab provides back fill protection as well as reducing potential frost heave and expansive soil damage.
EPS perimeter insulation is available in a number of densities providing compressive strengths up to 60 psi at 1% deformation.
I have skied many times since that cold January day many years ago, but I have never forgot the lesson that I learned that day. Don’t forget the gloves and when insulating a building don’t forget the perimeter insulation.