ASK A BUILDER
By CCHRC Staff
The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.
Q: How do I insulate my foundation and how much is enough?
Insulating a foundation is an important step in both retaining heat during the winter and reducing heating costs. Concrete or concrete block — the material used to build most Alaska home foundations — is very conductive. If not insulated, it will transfer heat from a crawlspace or basement directly to the surrounding soils or outside air. Many Fairbanks homes, especially older homes, do not have insulated foundations. Putting insulation on the outside of the foundation will slow that heat transfer and ultimately save energy and money.
The most commonly used insulation for new homes and when retrofitting older homes is rigid foam board that is rated for below-grade application. If an insulation is rated for below grade, that means it is less susceptible to water absorption and is not damaged as easily.
Another option is to hire a professional to apply spray foam to the foundation, which has similar insulative and water resistant capabilities.
Building code requires that new homes have R-15 of insulation installed on a foundation. That amount is equivalent to about 3 inches of rigid foam board. Insulation should be applied to the outside of the foundation all the way down to the footer.
Spray or foam board can also be applied to the interior foundation or crawlspace walls. This method saves effort because the entire perimeter of the home does not need to be dug out; the down side is that this method consumes interior living space.
Be sure that any interior insulation is either fire rated or is covered with a fire rated surface.
Q: I have wastewater pipes that have recently become frozen. How should I thaw them out?
Frozen wastewater can cause backups that can lead to a messy situation.
Heat tape will slowly thaw frozen pipes, but could require months of thawing.
There are ground-thawing machines that can be rented, but they are often difficult to use. The safest option would be to hire a professional to thaw the areas that need work.
Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at akhomewise@cchrc.org.You can also call the CCHRC at (907) 457-3454.