Posted by Dave on 19:04:44 2/24/2011 from 22.214.171.124:
Hi, I really like your site, it is very informative and a breath of fresh air. I was wondering if perhaps you had time to read my story and offer any advice as well.
A couple years ago, we (a young family) bought an A-frame cabin in the Pacific Northwest. The roof is very steep (33/12 pitch or about 70 degrees) and was originally cedar shake construction. When we bought it, it was covered in moss and leaking inside. Between the outside layer of cedar shakes and the tongue and groove (T&G) decking visible from inside, there was a sandwiched layer of styrofoam insulation... which now I know would have been perfect for carpenter ants, especially considering the moisture problems caused by the leaky roof.
A few days after closing on the house, and before we could move in, I got posted overseas, and we did not begin living in the house until a year after we bought it. While overseas, I had my general contractor replace the roof almost immediately. His roofers ripped off all the old cedar shakes and styrofoam boards, and replaced them with composite shingles. Instead of styrofoam, I asked for polyiso rigid board to be used for insulation. The polyiso was installed over the T&G (with roofing felt in between) and an air space between the polyiso and plywood/composite shingles that's braced by styrofoam spacers. It has continuous ridge vents but no soffit vents because my contractor told me the soffits were holding all the rigid insulation up inside the steep roof. The contractor told me he had to replace a few of the T&G boards which were rotted out, but he made absolutely no mention of any ants.
To make a long story short, one of the first things we noticed after moving in was carpenter ant frass (caught in spiderwebs) hanging in between T&G boards throughout the house. I didn't know what it was at first, and thought it was just bits of the old roof. I recently started remodeling the basement, found a nest of carpenter ants behind the drywall in a corner, and after doing research realized all that crud between the T&G boards was carpenter ant frass.
At this point I'm a little freaked out. I have frankly never seen a carpenter ant inside - just the frass. I was hoping that maybe what I was seeing was all leftover frass from the old cedar shake roof, which once cleaned, would not return. Now however I'm not so sure - it looks like new frass is appearing (though it's hard to tell) and once some dust did come down in front of my wife and I. What's most disturbing is that I spent $20k on the new roof (it is very expensive to re-roof an A-frame with such a steep pitch - I got multiple bids) and apparently have carpenter ants in the new roof. And according to your site, this is a real serious problem that has to be fixed perhaps structurally.
At this point, what are my options? I can't afford to rip the roof apart again. The house has several large pine trees that overhang it, so is likely always going to be fodder for carpenter ants unless I have an arborist take the trees out. I could drill some soffit vents myself to see if I can increase the air flow inside the roof. Also the house could be better sealed.
In the basement, there seem to be signs of carpenter ants everywhere - on the sides of the floor joists when I pulled out the fiberglas insulation, there were these long, sticky blackish-brown trails on the wood that need scraping off. Large quanities of frass everywhere. Also evidence of mouse nests (I got rid of these earlier by blocking all their entry points, but the old nests remained). Moisture problems caused by an incorrectly installed "permanent wood foundation" which I am replacing by jacking up the house and replacing with concrete (that's another story).
But the roof - what to do?
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