Sloped monolithic slab... with walls that are level

[bedn0009]

Hello,

If I am having a slab poured that slopes 2" from front to back (in 28") what is done to prevent the bottom plate (and thus the entire wall) from being out of level?

How is this done on a single pour with integrated footing?

Thanks

 

[The Cobbler]

you would need a curb around the perimeter that is level .

 

[bedn0009]

There are other options... anyone else?

 

[Jokenring]

Shims

 

[PugetDude]

Build tapered side walls so the studs are plumb and the top plate is level. ...fairly simple to do. The ends are framed normally, the front 2" higher than the back...

 

[Cyberbear]

As already mentioned, a curb or stem wall would take care of keeping the walls level. I presume the slope is for the usual reason of hosing the floor down to remove residue from the automobiles. The contractor forming the pour should know how to accomplish this. Always use lots of steel and a good grade of concrete mix.

 

[pstnbly]

When I frame walls directly on slabs or stemwalls I use the following method. Attach sill (pt), install bottom wall plate with stud layout, attach all corner studs without cutting to length, brace corner studs, use laser transit to establish grade marks on corner studs, determine wall stud height, mark wall stud height using grade marks for reference, pull a string line tightly around the building at the stud height, have someone help measure at every stud location and write that down at the stud location, cut studs to numbers and toe nail to the plate (use bracing if you have too), apply top plate.

This sounds like a lot, but it's really not, it's almost as fast as framing on the ground and every stud is custom matched to the slope or irregularity. I've framed the walls for 30' x 50' buildings this way in less than a day, by myself. I usually don't even brace the studs unless the wind is blowing, I just make sure I toe nail well with 16D sinkers.

 

[dfiler2]

I've put up many buildings on slabs and have never heard of sloping the entire slab, when a slab does need to slope it is done by sloping the edges to the middle and then a slope from one end to the other in the middle. As far as building the wall in place by setting the corners first, that might work but seems like a huge pain to me. I think I would snap lines on the floor that mimicked the slope and build the wall accordingly. Are you sure the slab is poured the way you say?

 

[readhead]

The concrete guys will simply put a tapered form on the inside of the wall to keep the perimeter flat and the floor sloped. After the mud has set up enough to hold its shape they will strip the form, fill in the stake holes and finish where the form was.

Is the building department making you slope the floor? Is it something you want? Personally I prefer the floor to be flat and put a short tapper at the doors to keep the water out. When you want to install equipment, a lift or tool boxes it is much easier on a flat floor.

 

[larry4406]

A competent concrete company can pour the sloped slab with integral level stem walls.

 

[larry4406]

Picture of stem wall forms. As the stem wall sets up, forms are removed and reserved concrete used to patch the locations of the 2x4 forms.

 

[bedn0009]

Right.. but I'm doing a monolithic slab, not footings or stem wall.

 

[readhead]

That is what Larry and I are trying to show you. Look at the pictures Larry posted again. You will notice the forms in the middle of the pour. Those will be removed during finishing as described.

 

[timewarp]

Around here they do it the same way pstnbly said, the only thing some do different which is the way I have done it is to cut your corner studs off to the correct height then instead of a string run a chalkline between them, then all you do is take your studs and set them on the marks on the bottom plate and rub them on the chalkline to get your mark to cut on. Makes it so you don't have to get up on a ladder to mark each stud when doing taller walls.
Also due to codes around here the garage floor needs slope, and they just pour the mono poured slab with a thickended edge and just let it slope.

 

[pstnbly]

Around here they do it the same way pstnbly said, the only thing some do different which is the way I have done it is to cut your corner studs off to the correct height then instead of a string run a chalkline between them, then all you do is take your studs and set them on the marks on the bottom plate and rub them on the chalkline to get your mark to cut on. Makes it so you don't have to get up on a ladder to mark each stud when doing taller walls.
Also due to codes around here the garage floor needs slope, and they just pour the mono poured slab with a thickended edge and just let it slope.

Slick trick

 

[larry4406]

Monolithic pours can be done with and without stem walls. The pictures I posted show the stem wall forms with a monolithic slab pour (ignore the foundation walls). This particular house has the garage in the basement, so the stem walls are integral with the slab.