Replies

1. 
   SaulK | Jul 23, 2014 01:44pm | #1

   Option 2 is the way to go. You can use a builders level or laser to shoot each stud height indiviually. Setting up a stringline would work, but I would still check your line with a level/laser to make sure it's not sagging in the middle. This way you are able to get a good positive connection (i.e. anchor bolts) from your plate to your slab, and it's easier to seal against air infiltration.

   If you do set a stringline, use a braided line. It's stronger, and you can pull it a lot tighter than your typical twisted line.

   Honestly I'd check your contract with the concrete company, assuming it's a new slab. That's bad enough, they should have to jack hammer it out and replace it.

2. GBA Editor
   Martin Holladay | Jul 23, 2014 02:15pm | #2

   Zane,
   Option 1 will also work (a pressure-treated sill plate and an untreated bottom plate, with shims in between). Three caveats:
   1. Make sure that you have a shim under every stud.
   2. Tie everything together with well-fastened wall sheathing.
   3. Consult an engineer if you are in a seismic zone or have any special concerns. The engineer's opinion is more important than mine.

3. 
   wjrobinson | Jul 23, 2014 05:25pm | #3

   Have the concrete company come back and overpour the slab level. Otherwise you still have a floor with quite a slope.

   If the sloped floor doesn't bother you then they could lay one row of any size block using a level string this time for the top edge of the blocks. The shim mix will need to have stone, larger stone as you get to the 4" thickness.

4. 
   STEPHEN SHEEHY | Jul 23, 2014 08:22pm | #4

   If the slab was placed recently, get a lawyer to send the concrete firm a threatening letter. 4" is way, way beyond acceptable.

5. Expert Member
   MALCOLM TAYLOR | Jul 23, 2014 10:19pm | #5

   Zane,
   As long as the slope is consistent you can still build the walls on the ground using differing height studs without having the top plate in place. We do something very similar laying out gable ends on subfloors.
   - Cut two studs, one higher than the other by the amount the slab slopes.
   - Attach them to the ends of the top plate laying on the slab, making sure they are at 90 degrees.
   - Snap a chalk line from the bottom of each showing the sloped bottom plate and cut all your studs to that line.

   However, as others have said, that's just the start of your problems. Everything you do from then on will be affected, from the drywall and sheathing, to the siding and any cabinets you might want to put in. Starting from a sloped base puts you behind the eight ball from the very beginning.

6. 
   user-5010253 | Jun 15, 2019 10:58am | #6

   Zane , set up a transit Find high spot I find a horrible foundation requires shims that start at 1/2” and go to 1/16”. Rip 4 shims for every size from 1/2” to 1/16” cut them to a length a little shy of the sill size. Take a hammer tacker staple sill seal to pressure treated sill when you’re shimming put shim directly on foundation to bottom of sill seal. After leveling at every anchor bolt find you wall layout and put a shim under every layout and bearing point. Take a picture of your shim job and send it to the concrete terrorist. Lol. Let sill settle after you put walls up then use spray insulation at every gap between foundation and sill.

1. Expert Member
   MALCOLM TAYLOR | Jun 15, 2019 11:58am | #7

   Dirk,

   Zane's post is five years old. If he hasn't managed to frame the walls by now he's probably got bigger problems than the uneven slab.