Thursday, January 7, 2010
Snow Trouble - part 2
Our roofer Alan tells us that attaching the flashing to any kind of masonry chimney is difficult, but attaching it to a stone chimney can be especially problematic. I’ve posted in the past about some of the challenges we’ve had with the chimney at the Hawksbill Cabin – during heavy or driving rain, sometimes we’ll get some water on the surface of the chimney inside the living room, and we did recently on one of the warmer days when there was snow melting up there on top of the chimney.
Alan has been good about coming out to check up on the flashing sealer and even has reapplied it once. His visits always conclude with the invitation to “come on up on your roof to check this out!” I demurred while there is snow up there but I’ve gone up there most times to follow-up with him in the past. Here’s a post about the last visit - http://hawksbillcabin.blogspot.com/2009/10/up-on-roof.html .
After he came out in the fall to reapply sealer, we had Jesse come over to work on the flat concrete surface at the top, to make sure we weren’t getting rain coming down from up there on the inside, appearing again on the outside of the chimney once it got below the roof of the chimney. Earlier Jesse had re-pointed and done some additional work on the chimney, as described in this post: http://hawksbillcabin.blogspot.com/2008/10/chimney-cap-repair.html .
We’ve talked to some other folks about potential solutions, as Alan outlined one for us and we wanted to double back for a second opinion with some historic preservation specialists Mary knows. I even have some little hand-drawn sketches of this solution, but they didn't scan well so I can't post them. (Note from February - there is a photo of the new flashing solution in this post: http://hawksbillcabin.blogspot.com/2010/02/chimney-chore.html).
The approach that they have proposed involves sawing into the masonry to a depth of an inch or so, then inserting the flashing edge into this line. The flashing would then be bent down at 90 degrees, running to the roof surface (the existing flashing layer would be left in place and this new layer installed over the top of it.) A small fold would be made at the roof surface and the flashing will extend another four to six inches over the surface. Then a mechanical attachment would anchor the new flashing to the chimney, in addition to the normal sealer that is applied.
The advantage of this solution is that once water hits the chimney, it will either be forced into the flue, where it will harmlessly evaporate, or it will be forced outside, running harmlessly across the roof to the gutter. That's how we hope things will work, at least.
If this flashing solution doesn't work, we still have two potential solutions to try. The first is a chimney cap, which is shown in the photo here - scanned from the cover of Atomic Ranch magazine, Fall 2009 edition (back issue at http://www.atomic-ranch.com/store/index.php?main_page=product_info&cPath=1&products_id=33 , this is the "Dansk Weinerbrod" article, and note roof line, etc., and similarities to the Hawksbill Cabin!). I've shied away from this alternative because Mr. Thompson left an inscription "1949" up there (one of three such inscriptions we've found - another at the base of the chimney says "Thanksgiving 1948" and a small concrete repair in the back of the house says "1999.") - but this may be moot due to some later repairs that obscurred the 1949 date.
The other, and ultimate last resort solution, will be to apply masonry sealer to the stone work. I'm satisfied that we have two steps to go before we get to this one though. I hope the new flashing solves the problem.
It is a true home-owner dilemma, in any case.