GALVANIZED ROOFING AND ROT
GALVANIZED ROOFING AND ROT
(OP)
I AM CURRENTLY LOOKING AT TWO SETS OF DRAWINGS (HOME PLANS)
THAT CALL FOR STANDING SEAM GALVANIZED ROOF. ONE ASKS FOR A
PLYWOOD ROOF DECK WITH TARPAPER UNDERLAYMENT, ANOTHER WITH
1X6 BOARDS WITH 1" SPACES AND A TARPAPER UNDERLAYMENT OR ROSIN PAPER, I HAVE BEEN TOLD THAT A METAL ROOF CAN "SWEAT"
AND POSSIBLY ROT THE WOOD STRUCTURE.WHICH WILL WORK BEST,
OR IS THIER ANY CONCERN? THANKS.
THAT CALL FOR STANDING SEAM GALVANIZED ROOF. ONE ASKS FOR A
PLYWOOD ROOF DECK WITH TARPAPER UNDERLAYMENT, ANOTHER WITH
1X6 BOARDS WITH 1" SPACES AND A TARPAPER UNDERLAYMENT OR ROSIN PAPER, I HAVE BEEN TOLD THAT A METAL ROOF CAN "SWEAT"
AND POSSIBLY ROT THE WOOD STRUCTURE.WHICH WILL WORK BEST,
OR IS THIER ANY CONCERN? THANKS.






RE: GALVANIZED ROOFING AND ROT
The OSB or plywood sheathing is easier to install and will probably be cheaper due to labor costs. The spaces in 1x6 stripping will provide some ventilation if the sheet metal is installed directly on the wood, but the felt helps mitigate the noise of rain and provides a little extra layer of leak protection.
RE: GALVANIZED ROOFING AND ROT
Plywood underlayer is used where loads need to be spread out, particularly with heavier roofs such as EagleLite or MiraVista.
Felt is sometimes for steel shingle roofs, but that's because the tarpaper is separated from the steel by slats that the steel is mounted on.
My aluminum roof sweats quite a bit. I suspect most other materials also sweat, but their water absorption is high enough to disguise the effect. Aluminum and steel don't absorb, so the sweat is more obvious.
TTFN
RE: GALVANIZED ROOFING AND ROT
RE: GALVANIZED ROOFING AND ROT
Suggest tarpaper over minimum 1/2" OSB or plywood deck. This system is considered a hydrokinetic system, designed to breath. Condensation between metal and tarpaper either vaporizes or drains to eave and or valley trim. Plywood deck reduces substantially noise from rain etc. Also solid deck will reduce oil can tendency, inherent in standing seam