An addition to my house which is now underway includes a covered (but not enclosed) porch. I’m thinking the floor should have a little bit of pitch so that water can drain. The builder says no pitch needed since it’s covered. What’s the right way to go on this? If it should be pitched, how much? Is there an easy way to add some pitch after it’s been built?
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Chuck if the floorboards are spaced with a gap between the water will excape below so no pitch is needed. Or if the porch floor is concrete it should have a 2degree slope as a garage floor would.I am sure this will be the standard reply but keep in mind Im a Canadian eh.
If there's spaces between you decking you don't really need any pitch, but 1/8" in 12" is nice to have. If you have T+G decking you definately need some pitch, up to 1/4" in 12".
No easy way to add pitch after it's built. I suppose you could take a chainsaw to the support posts but I don't think you really want to go there....
IMHO, absolutely should be pitched. Also, floorboards should be run perpendicular to porch edge. Some folks say 1/4 inch per foot, but I think you can get away with half that for a covered porch if it is set carefully.
Why pitch?
1) Standing water=puddles, mildew, algae, and rot. Even synthetics get mildew and algae.
2) Standing water=ice (in some climates)
3) Any water that does not get pitched away lands closer to house, which can cause other problems.
4) If not purposely pitched away, it may wind up being pitched slightly towards the house, which can rot the house. Proper flashing can prevent, but why bother when you could have simply pitched it away in the first place.
Pitching later could be a challenge.
Jinx.
Agree on pitch, and can't say that I know of any hard and fast rules that say it must be such and such. I've always been a 1/2" in 8' guy myself. On a deck that stretches 24ft from the house, that's only inch and a half, but you don't need much. Just a little insurance. If you went with 1/4 every 2' as suggested, that'd be 3 inches. Still not unreasonable, but certainly enough.
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