Seeking advice on options for full roof replacement in San Francisco Bay area house
I am a “newbie” to this group and hoping this question is appropriate.
We are first time homeowners whose 90 year old single story craftsman cottage needs a new roof installed. Our city code desk advises that the current asphalt shingles & cedar shake layers currently laid over 1×6 fir boards (with spaces between) must be totally removed and new deck sheathing installed under a new roof.
Having never replaced a roof before we are now trying to wade through the myriad products for decking, underlayment, roofing etc. to try and determine what the “best” options might be before we contract with a roofer.
Preliminary estimates from several local roofers were based on 1/2″ CDX plywood decking, 30 lb. felt underlayment and 30 year rated asphalt shingles. The estimates given were not inexpensive but in a range we can afford. The roofers advised us that because our climate is so moderate there is no need to consider more expensive options for decking and underlayment … but we wonder if some additional expense for products available that might enhance the roofs durability or be better environmentally could be justified.
Any advice on this would be much appreciated.
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I would not be comfortable w/ 1/2" plywood, though I guess it is fairly common. The roofers I have spoken with always say to use 5/8", and that is what I've used on the few roofs I've put on. The rest of your question, I don't know.
John, the 1/2" ply is fine if it's laid over the skip sheathing. If it's over 24" OC rafters, then 5/8" is a much better choice.
Word of advice, whoever does the job should completely re-nail the skip sheathing to the rafters before the new sheathing goes on. The original nails are probably plain steel and may be rusted away. They definitely were on my old house, which had cedar shake for most or all of its life. Send a guy up there with a nail gun and a box of ring-shanks and have him nail it all off.
I agree with the roofers that you don't need anything too fancy. CDX plywood, 30# felt rated to ASTM D226, and shingles installed using fasteners and details specifically per the manufacturer's written instructions. All the flashing should be brand new. Any masonry chimney or other flashing details need to be done by someone highly proficient.
Sorry. I did not see the part about the 1x6 boards.