Here's a roofing question. I already know the answer but i'm looking for someone to tell me it's ok......
I put a very expensive standing seam roof on house and separate garage. Ate up a bunch of budget! I told the roofer, i want the same roof as the one on the bank.
Over the years Ive found that every hole in a roof is a source of problems, eventually. Working for my contractor brother we replaced many sky lights, every new generation guaranteed not to leak.
I call BS!
Years ago, I vented a-washer drain into the attic. The home depot guy sold me a plastic vent cap that went on the 2 inch pvc and bingo, i was done. He assured me it was legit.
On my new house i asked the plumber to limit the vents thru the roof, or to eliminate them all together, vent it to the attic.
Nope, he said code says i must have at least 1 pipe going thru the roof and it must extend so many inches blah blah.
My roofer said, the plumber puts in the vent. The plumber says, the roofer puts in the vent.
Turns out, nobody put in the vent and i just passed final inspection yesterday!
Again, my brother the builder says i must vent to the outside for 2 reasons. Humidity from the open vent pipe in the attic and....the oder from the waste.
I can't argue with the humidity issue but, isn't the p trap supposed to stop the oder? And If necessary, couldn't i put a dehumidifier in the attic?
My roofer did suggest that when cutting the hole, cut a 2 inch hole in the metal and a 4 inch hole in the osb underneath. The vent cap is then secured only to the metal, not into the osb. He said do that so when the metal and wood expand at different rates etc, it won't cause ripples in the metal.
So....do i vent thru the roof or into the attic?