The first day of summer isn’t until June 20th, but you would never know that if you walk outside. Unfortunately for some of us, we can tell it’s hot just by walking into the room over the garage. For some, it’s just an extra room, for some it’s the master bath or walk-in closet, and for those unlucky ones, it’s the master bedroom. So what causes these rooms to be hot?
Often, the problems are actually a combination of things and home owners tend to grasp at straws by bringing in various contractors to figure it out and fix it, which can get expensive. Over the years I have seen some “interesting” approaches to dealing with these rooms. The most extreme was an attempt to close off the room to the rest of the house by closing off all the vents and adding weather stripping to the door to seal it shut. I wonder if those people realized that the mortgage payment includes that room too???
One of the biggest culprits are knee walls. These are the vertical walls between interior space and attic space. They are also a big reason why those same rooms are cold as I wrote about before. The problem is that those walls are subjected to the same temperatures that the rest of the attic is exposed to, yet the minimum R-value for the floor of the attic is R-30. Considering that most of our knee walls are insulated with poorly insulated fiberglass batts, you can see where the problem comes from.
What’s the best way to deal with these? It depends. In the last home we were in, the answer was cutting an access hole in the knee wall, installing foil faced rigid foam board to the backside and sealing the seams. Then we installed a passive vent in the wall above the door because there was no return air vent in the room. After treating the knee walls and allowing for better air flow, there was no difference in the room temperature from the rest of the house. A relatively inexpensive fix that makes the room more comfortable and saves money on the utility bills.
So before you waste a bunch of money on some crazy high tech or low tech solutions, do yourself a favor. Talk to a person with a background in building science. They will not only be able to pin point the actual problem, but give you the most cost effective way to fix it. Because as I always say….Don’t throw money at your problems, throw knowledge, it’s a lot cheaper.