from Seth in Minnetonka, MN :
#998
I have a story and 1/2 home built in 1934 with Stucco exterior and plaster walls. I've insulated the attic, new windows but still am having issues with the upstairs staying warm and cool. Is it worth it to have the wall cavities filled? If so, with what?
Properly air sealing and insulating your home can help with heating and cooling.
1½ story homes are difficult to heat and cool unless you properly air seal and insulate using one of two methods. One method is to air seal the floor cavities under the knee walls, air seal and insulate the knee walls (it is common to use unfaced fiberglass), and insulate the floor cavities that extend outward from the base of the knee walls to the eave. Make sure you air seal and insulate the top plates of the 1st floor exterior walls and don’t forget to insulate the sloped ceilings. It is very important to install an effective air barrier over the knee wall insulation (unless you would insulate using an expanding foam product). The best choice of materials to use as an air barrier over fiberglass is foil-faced rigid board insulation (i.e. Thermax®). An alternative to rigid board insulation is to install housewrap over the fiberglass knee wall insulation. This method creates an unconditioned triangular shaped attic space.
An alternative method is to insulate the rafter bays from the top of the sloped ceiling all the way down to the eave to include the exterior wall top plates. When insulating in this fashion, the gable end walls need to be sealed and insulated. This method creates a conditioned (or semi-conditioned) space. Home Energy Magazine provides some great information to help you learn the details (with illustrations) of both methods.
Now, let’s address the issue of the wall cavities. I assume you are referring to the gable end exterior walls of the 2nd floor. If so, the answer is yes, it is worth it (energy savings and improved comfort) to have the wall cavities insulated. The most common method is to have them dense-packed with cellulose or fiberglass. This can be done from the interior by an experienced crew. Give consideration to insulating the 1st floor exterior walls as well if they are not already insulated.
You can also get more in-depth into how your home is using, or wasting, energy by having a thorough home energy evaluation conducted by a professional trained through Focus on Energy's Home Performance with ENERGY STAR Program. Our expert consultants will conduct a thorough inspection of all the systems in your home and identify problems such as air leaks and drafts, moisture, cold spots and more. You'll receive a written report of the findings and a list of recommended solutions.
Published Tuesday, March 01, 2011