We are on the threshold of winter here now. It often falls below freezing at night now, but then it gets warm during the day. It won’t be too long before it stops doing that, and then we’ll have our first snow. After that, we’ll start having ice dams on the roof.

Ice dams are caused when the heat from the house melts the snow, but the air temperature above is still below freezing. The snow melt runs down the roof until it gets to the eaves which overhang the house. Because the eaves are hanging over the edge of the house, they do not get warmed by the house. So the water freezes. This builds the ice dam which can cause water to back up onto the roof and stand in a pool. Then the roof leaks.

Last year I installed some eave heaters to melt the ice off the eaves, but running those cost us something like an extra $120 per month. Ouch! We turned them off rather quickly. That is neither a green nor a financially sound way to attack ice dams. It is better to keep the roof cold, so that’s what I started working on tonight.

Our attic floor is insulated, but we have a stairway leading up there. Our attic is very large and open with a subfloor, and we store gobs of junk up there. The door to that stairway is not insulated, and the heat from the house whooshes up almost unimpeded. When the snow on the roof melts, it always melts right above that stairway. When we bought this house, I also bought several rolls of insulation for the attic, because I wanted to finish it out. Unfortunately, I bought the wrong kind, and lots of it.

I bought rolls of R13, which is great if you want to insulate a wall built with 2×4’s (meaning a 4″ thick wall). Our rafters are 12″ wide though, and I found after buying all this stuff that it’s not legal to insulate it with only 4″ of insulation. I hauled all this insulation to the house in a moving truck that we used to fetch our things out of storage (while we had it), so taking it back was not going to be an easy thing to do. Instead, I asked the building inspector if I could just slap three layers of R13 insulation up there, which would take me to R39 (basically). He said “no problem.” But I never got around to doing that.

The next thing to consider is that it is very important to leave an airway from the eaves to the ridge vent. This keeps the underside of the roof at the same temperature as the upper side, unless you have a blast of heat whooshing up from the stairway. If you just slap the insulation against the underside of the roof, all kinds of bad things happen. So I bought some styrofoam panels made for just this reason. These get stapled to the underside of the roof, and the insulation goes on that. The styrofoam panels provide an airway, and all is good. I hung about half of these a couple of years ago, and that’s where this project stalled. Tonight I unstalled it.

I went up there after dinner and hung two layers of insulation between three of the rafters. It still needs a third. I did this by unrolling the R13 and folding it in half, then wedging it between the rafters and stapling it in place. The third layer will follow later. After I did three rows of this, I counted rafters and rolls of R13. I’m going to need another two dozen rolls. But maybe I should get some R39 instead of R13, I dunno.

My plan is to put up two layers for now, covering as much of the roof as I can, and then go over it with the third layer. I think that having the entire roof covered with two layers would be better than having some covered with three and some covered with zero (at least temporarily). I need to plan out how I’m going to do this though (buy more R13, or get some R39? How much?) Also, I may get a tax credit for buying insulation. Can’t get a tax credit for the stuff I bought five years ago.

Three rows is not a lot of progress, but I ran out of time before I needed to get Beth to bed. Also, it’s hard work and about wore me out! If I can add three rows per night for four nights a week, I should have this whole thing zipped up before Christmas. Or maybe that’s how I will spend my Thanksgiving break, who knows? Anyhow, this should greatly help both the heating bill and the ice dam problem. And it’s long overdue.

Don’t think I’ll be able to work on this any tomorrow, and before I start again, I want to get some dust masks and find my safety goggles. Maybe wear gloves too. Insulation is nasty stuff!