1:12 Pitch Roof And Water Pooling

KesslerDweller

I have modern house I am working on with a 1:12 pitch roof. The roof is a commercial grade torch down that does not leak. I have noticed after a rain that there is some areas in which water pools less and a 1/8 inch by 3 feet in diameter. 99.99999999% of the water drains out but because the slope isn't perfect or high pitched, there is some left over water. The left over water evaporates in a day.

I have talked to my roofer and he says that because of the pitch of the roof not every single drop of water is going drain. I want to get this straightened out with repairs if necesssary before I give him his final check.

Anyone have any advice? If the roof doesn't leak, is there any concern?

Home inspectors have complained about this before, but inspectors I have seen all complain about something - that is their job.

woodmagman

It is going to depend on the area of the roof, if the framer leveled evey beam proper. Is every joist dead on straight. In a year or two the house will settle and pooling could change locations. Water needs 1/4 inch per foot to flow correctly. The fault seams to be prior to the roofer coming on site unless he is the one setting the slope...what does his contract state.

tinner666

According to GAF and the other manufacturers, water that evaporates within 48 hours does NOT constitute standing water. Mod-Bit is 4mm thick and each lap will be 8mm thick. That will create a lot of 1/8" pools of water. a 2/12 slope would have been nicer.

Are all the seams sealed? Are the walls done properly? Any fishmouths? These will be your concerns.

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Frank Slate Roof Repairs, Richmond, Va.

KesslerDweller

It would likely fall back on my framer and/or truss company but it is probably not worth it if GAF says standing has to be around longer than 48 hours.

Thanks for your input!