Post Number: 208
|Posted on Saturday, January 26, 2008 - 02:12 pm: ||
Number 1: The lack of longevity of plywood. The oldest slate roof I have looked at had roof decking of 1" pine that was 215 years old. We work on slate roofs regularly that are about 120 years old. Plywood does not have this longevity.
2: Ventilation. Peel and stick membrane creates an external vapor barrier, which, in cold climates, can cause condensation to occur on the inside surfaces of the roof deck. If the deck is plywood, this will further accelerate delamination and failure of the plywood.
3: The peel and stick underlayment will crack and curl over time under the heat of a slate roof and interfere with the use of a slate ripper, the basic tool used when repairing a slate roof. The ripper slides underneath the slates, but when there is a thick underlayment that can interfere with the use of the tool, it makes repairing the roof a headache because the ripper gets hung up on the underlayment.
4: The traditional decking and underlayment work just fine, so why change the system?
Slate Affair Inc.
Post Number: 159
|Posted on Saturday, January 26, 2008 - 08:21 am: ||
Theres alot let venting for the slate.
Post Number: 1
|Posted on Thursday, January 24, 2008 - 04:58 pm: ||
I just read and really enjoyed your article, "What You Need to Know to Keep a Slate Roof Alive for Centuries." I have a 58 year old slate roof on my house and have been in the roofing industry for the past 5 years, first with Elk and now with Grace.
You mention in the article that "the trend toward membrane-covered plywood decks under slate is a trend that will create a whole new set of problems for the slate roofs of the future." What kind of problems do you see happening with this type of roof construction?
Thank you in advance for your response.