Since we received some nice snow recently, Laura and I decided to go for a walk in it. We did our usual route – up the road and back. It’s two miles and just long enough to get out whatever it was that we needed to get out. Remarkable how that works. Take a break to loosen up a bit.
Anyway, as we walked out of the house and onto the sidewalk, I noticed that the roof of the log cabin room had some snow melt. I looked at the roof, looked at Laura and then looked back at the roof. I said, “That’s not supposed to be like that. I just insulated that room. Why is the heat from inside still coming through to warm to roof?”
Snow Melt on Log Cabin Room Roof
Snow Melt on Roof
As I stood there on the sidewalk, somewhat disappointed, I began to wonder why the melt was happening. I decided to walk around to the back of the house to see if the same thing was happening on the other side of the roof. If anything, there should be more snow melt back there because that’s the side the wood stove is on. It gets mighty warm in there. Also, the roofs are facing east/west, so neither get much sun. I’d say things are about equal, especially during winter. Do you want to see what I found on the other side of the roof?
Snow on Roof
Well, isn’t that interesting. Little, if any real snow melt on that side. Something was going on.
A few weeks ago, I installed rigid foam insulation on the back side of the ceiling in the log cabin room. As I did this, I sealed (with silicone caulk) around the large cross beams that go from one side of the room to the other. My caulk sealing basically made that side of the ceiling water tight. I like to say that if you tipped the room upside down, you could fill it with water. No leaks.
Taping Rigid Foam Insulation
Sealing Rigid Foam Insulation With Silicone Caulk
I also taped all the seams between the pieces of rigid foam on that side as well. I already told you, though, that I plan on removing the tape to seal with silicone.
It only took a few moments for me to realize what was happening and why snow was melting on one side of the roof, but not the other. I sealed one side of the ceiling, but not the other side.
Rigid Foam Insulation Around Cross Beam
Unsealed Rigid Foam Insulation
After I realized this, I made a mental note of where those large beams were located inside and then lined them up with where the snow was melting. Amazing how much heat loss can occur from such small unsealed openings, isn’t it?
What’s the lesson here? Insulate with anything other than fiberglass (air travels right through fiberglass insulation) and be sure to air seal the hell out of your air-tight insulation. It’ll go a long way.