Covered Slab Slope

[jrdepew]

Hi All ,

I am about to start forming up a concrete slab at the back of the house for a screened in porch. I will likely hire the actual pour, and do all of the excavation, rebar, etc myself. How much slope should I have on the slab? Since it is covered, I was going to go with a very gentle slope, about 1/8" per foot. 1/4" per foot seems extreme because the roof will do most (all) of the water shedding.

Thanks,
Joe

 

[boggen]

dimensions of porch?
shape of porch?

frost depth for your area?

any pictures?

account for footer, and any settling/ movement / cracking of the slab.

your local concrete companies / contractors. will more likely be better suited. to give you an idea of what you need to do. for footer width/depth if any, and how thick the pad needs to be. and if you need any "joints" were concrete can crack if it needs to crack. due to ground movement / settling issues.

if large area, perhaps a drain. so you can push any mop water, or like down the drain.

 

[EddieWalker]

Since it's going to be covered, there is no reason for a slope. Make it flat.

 

[/pine]

Since it's going to be covered, there is no reason for a slope. Make it flat.

Agree...unless you're expecting "some" rain etc. blowing in through the screening and plan on having some sort of sill where it can drain out/off...

 

[Cataclysm]

Hi All ,

I am about to start forming up a concrete slab at the back of the house for a screened in porch. I will likely hire the actual pour, and do all of the excavation, rebar, etc myself. How much slope should I have on the slab? Since it is covered, I was going to go with a very gentle slope, about 1/8" per foot. 1/4" per foot seems extreme because the roof will do most (all) of the water shedding.

Thanks,
Joe

1/8" per foot is a lot of slope. 1/4" per foot can be hard to walk on especially for the elderly.

I would find some sloped slabs and walk on them and measure the fall and see what felt ok to walk on and still shed water. It isn't going to take very much to shed a little water.

 

[Stimw]

If you know how to read a level there is a secondary line on most bubbles that gives you angle for drainage.
I think it is 1%. ???

 

[Deere Dude]

Rain will get in unless the porch is walled and windowed. Unless you feel like mopping and squeegying it every time it rains, I would slope it at 1/8" per foot, or at least some slope.

 

[/pine]

FWIW... a 1/8" to 1/4" pitch is typical for the average garage floor slab...

 

[dragoneggs]

Rain will get in unless the porch is walled and windowed. Unless you feel like mopping and squeegying it every time it rains, I would slope it at 1/8" per foot, or at least some slope.

And periodic hosing it down to clean will be easier to deal with as well.

 

[Deere Dude]

And periodic hosing it down to clean will be easier to deal with as well.

Most floor drains in a factory I worked at were higher than the floor.

Take into account that the floor contractor might not get it perfectly flat and may have a little dip or two that will hold water even if pitched correctly. So a little pitch will make that scenario more difficult.