spray urethane on cathedral ceiling
I have a 150 year old farm house in which I have just gutted one of the upstairs bedrooms with the intention of spraying urethane insulation on the underside of the cathedral ceiling as well as a short ( 3 feet) knee wall below in an attempt to curb an ice damming problem.
The roof is shingled and, on the other side of the short knee wall is a extension to the house that was added some forty years ago. Now I know that it is ideal to provide ventilation to the roof in the form of baffles in a cathedral ceiling however, although I can vent the baffles into the attic at the top of the cathedral ceiling, there is nowhere to introduce air at the bottom as it buts into a 4 x 6 beam at the top of the knee wall. I know that applying 5 inches of urethane on the underneath without baffles will shorten the life of the shingles & possibly introduce dry rot so, should I install baffles anyway ? Oh, have I mentioned that the insulator is coming in 2 days and, that we already have about 8 inches of snow on the ground ? The joys of procrastination !!
I’d appreciate any and all feedback.
Thanks,
Maisonneuve
Edited 11/27/2008 1:27 pm ET by Maisonneuve
Replies
Greetings M,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
94969.19 In the beginning there was Breaktime...
150 years isn't exactly "maison neuve!"
Curious what you ended up doing. If you went with closed-cell foam you would be fine without venting (assuming your climate is not too extreme). No problems with rot or shingle life unless other details are not done properly.
If you went with open-cell foam...well, you might be ok, but hopefully you went with closed-cell.