Building wall on angled floor

Hi Guys,


I have attached 3 pictures of a doorway in a garage. I removing the roller doors and building a wall to fill the hole. The floor for the bottom plate is on an angle and I just wanted opinions on the best way to tackle this. Probably the cheapest way and also the best way.


Thanks.

 

I would bolt a pressure treated sill plate (2x4) down to the concrete. Then I would measure the angle and cut the end of my studs to match the angle, checking the angle at each location as you move across the opening. The angle of the concrete may not be constant and measuring and cutting each stud will allow you to accommodate any variation. When cutting I like to cut the angled end first, then measure up from the heel or toe of the angled end for the cut on the other end to get your final length.

Another way would be to build the wall lying down on the ground. With careful measuring you can build the whole wall flat on the ground and then stand it up and put it in place. This method allows you to toe nail into the studs and can be faster to build. The downside is if you are off on a measurement you might not realize until the whole thing is built and you try to fit it in place. Also it could be more difficult to match the angle of the concrete.

Whichever way you go you need to use pressure treated for the board that touches concrete. And, you must use fasteners approved for use with ACQ treated lumber. Normal, un-coated nails may quickly rust away in contact with the pressure treated wood.

 

PD, that's what I was thinking but if you mount a PT bottom plate directly to the concrete - won't the angle of each edge pose a problem when you attach the plywood [exterior] and drywall/baseboard?

btw - welcome to the forums bigbob!

 

The bottom edges of the sill plate should be in or out by less than 1/2". On the outside you just stop the sheeting where you want and the bottom inch may be unsupported. The sheetrock on the inside I'd leave up from the floor 1/2" to 1" which will keep it clear of the edge of the sill that's angled in. This spacing off the floor will also help prevent the sheetrock from wicking moisture up from the concrete. It also helps if you ever spill or get water in the area. A normal puddle or spill is not deep enough to get to the sheetrock. You just cover the gap with base molding.

 

makes sense

need more characters

 

Great advice guys, thanks for the help. I just thought of something. See attached image from a profile view. The red line is the attached sheeting, the orange is the skirting around the floor. How will I cover the gap with skirting when the base plate will be on an angle?

 

What type flooring will you install? You could always angle rip the bottom plate along the inside to reduce the jut out.

 

When you cut the angle on the bottom end of the studs, the cut will be longer than if it were cut square. I will spare you the long math details.

Hope this helps.

If in doubt, do as Chandler suggests, and rip the bottom plate at an angle.

Also, the inside wall covering thickness will help build out the difference.

 

If your interior wall is sheeted with 1/2" thick gyp. board, that should get you out far enough to clear the bottom corner of the sill plate. If you draw the thickness of the sheeting to the same scale as your stud instead of just as a line it should show it (the sheetrock should be about 15% as wide as the 2x4 in your drawing)

 

Don't think it's been mentioned...
You could use a 2 x 6 and rip BOTH interior and exterior at an angle. Basically you turn a rectangle into a parallelogram. But when you put it on the slope the ripped edges would then be vertical.

You'd want to check the width of a stud cut to the right angle...then make sure the 2 x 6 is cut to match.

 

Thanks again for the replies, now my wife is trying to talk me into putting french doors there instead. I think the only option now is to get a wedge cut for the area to make it level for the door?

 

Or you could just use a 4x4 for the base plate and rip an angled slice out of it to match the angle of the floor. After you make that one cut, everything else conforms to standard horizontal and vertical procedures. Problem solved! Just use treated 4x4. Cut the slice out of the base plate that leaves 1 1/2 inch thickness on the narrow side.

 

I would be concerned because the framing/siding is so close to the slab for rain splash-back. 2" is allowed for stucco, others are usually 6" per code, check with local AHJ. Your siding choice is very important, especially if on the "weather" side.

P.t. wood is treated against insects and microbes, not waterproofing, unless special ordered. Moisture can still wick through it to your new studs; Pressure-Treated Sill Plates and the Building Code | GreenBuildingAdvisor.com

Use hot-dipped galvanized fasteners or s.s. and a c.c. foam sill sealer for air/capillary/thermal defense.

Gary

 

I believe the 4x4 method is good. Splash back can be handled by proper flashing as evidenced on the old part of the building, bringing it low enough to prevent water from getting to the pt. Pressure treated can be ground contact rated and with the foam barrier and a good exterior sealant can be used in this situation.