Volunteering brings many joy’s. Volunteers opinions also vary greatly. As a long time volunteer I am now involved with a childrens summer camp with Lots of work!
One problem is a number of buildings need to be re roofed. These existing wooden buildings are approx. 20 x 40. The roof is sloping aprox. 30deg from the back 40 covering 2/3rds of the building and approx 45deg on the front 1/3 of the building. I’m assuming from a visual inspection that the roof is made of 2 x 6 construction, fully vaulted, non insulated, with plywood underside and a outside continuous strip vented (4″) on the overhang soffit. No ridge vent or other roof ventillation to be seen! (hence the current premature deterioration of the shingles..3 layers thick!).
Some of the toolbelt volunteers want to just cover the roof with metal roofing sheets, supposedly heat reflective, right on top of the existing roof using 3/4 ” strapping nailed on horizontally first.
I believe the roof shingles should be stripped, repairs made to the sheathing, facia and soffit where required and then resurfaced…question is with what??? Will not the metal roof turn the cabins into ovens in the sun or are these metal roofs truly solar reflective? How long does this reflective finish last? (camp has been around for 50 years and the cabins for 40) What about lightning? on metal roofed buildings will we need to add lightning protection? If metal is the way my opinion would be to insulate the roof.(weatherwise we are in Southern Ontario)
Anyways any help is appreciated.
Doing it right the first time is how my dad taught me to build and I am working with short-cut-sams.
Replies
Definitely do the total tear-off. Give it a vented ridge while you're at it. My attic's cooler with a ridge vented copper roof than it used to with tile.
-- J.S.
I can't imagine adding another layer on top of three layers of shingles. Go ahead and do the full tear oof and add the tin roof. Here in south Texas the metal roofed houses are noticeably cooler.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I would do the tear off, replace any bad sheeting, add purlins at 24" O.C., a layer of 1/2" super tuff R over that attached with cap nails or staples, and then the steel roof. Any rood is only as good as what's underneath and three layers of shingles is a LOT of weight... plus if the sheathing is bad it allows whatever is on top to move causing premature failure and other problems.