Framing interior wall on concrete

Truth

I am building a wall to make two rooms out of my former garage. The floor is concrete. I will be putting down a 6 mm vapor barrier on the floor. Do I need to put that barrier under the pt wood that I will use as my base plate for my wall of which I plan on anchoring to the floor? I also have approximately 1/4 to 3/4 of an inch difference in the level of the concrete over the 20' span where the wall will go? Can this be shimmed and is there such a thing as pt shims? Thanks for advice in advance!

joecaption

No need for the plastic under the PT.
And no there are no pressure treated shims.
Cedar will work.

abracaboom

Put your p.t. plate all the way against the concrete (no shims) and cut each stud to length. Or put your p.t. plate against the concrete (no shims) build your wall with two plates and all studs the same length (shortest length) and shim between the two bottom plates. I would never shim between the plate and the concrete.

Truth

Thank you very much. I'm quite new to this kind of work, I've looked up videos on how to frame out a wall but I have yet to understand if I need a 2x4x20 for the top and bottom plates or if using 2-10' 2x4's is ok. Also is it ok to attach sheetrock to pt wood? I'm a handy lady who has lots of tools and has done many projects but never frame a wall. Sorry if my questions seem so elementary. I'm very grateful for the advice.

Truth

Thanks Abracaboom! That makes sense. So instead of building the wall on the ground and installing. First install pt plate, then another base plate w shims where necessary. Intall top plate to cross ceiling joists then toenail the studs into top and bottom plates at the proper lengths? That makes great sense to me, am I thinking right?

mae-ling

I would build the wall with only one bottom plate (the two idea is not wronge just different) then shim and nail at the top. A little faster and easier to plumb

If you are framing on 16" centers use a 16foot and a 8foot and alternate the top from the bottom so joints are not on same stud.

Yes it is fine to attach drywall to PT wood.

Truth

I just reread what you said. I get it... Sory for the delay in understanding. Is it ok to attach sheetrock to pt?

abracaboom

In both cases, the p.t. plate would be bolted to the concrete first.

If you use only one bottom plate, cut each stud to its unique length and toenail.

If you use two bottom plates, build the wall on the ground (with the second bottom plate, top plate, and all studs same length), lift the wall over the p.t. plate, and then shim. This uses one more plate but you don't have to toenail or measure each stud. If you use bolts for the p.t. plate, plan ahead how you are going to deal with the nuts and the second plate.

mae-ling

You can also use one bottom plate and shim at the top. 3 different ways of achieving the same thing.
It sounds like a non-load bearing wall I would nail it it with concrete nails and a gun (ram set or the like) or use concrete screws. Drill a hole and put in the screws.

Truth

I was planning on using tapcon concrete screws. I was going to counter sink them.

mae-ling

Sounds good. No need to over countersink them,just pull the plate down tight.

abracaboom

If you use two bottom plates:

The p.t. plate can be 2 pieces 10' long each.

To go over this p.t. plate, you can build two walls on the ground, each just over 9' long (16 gap between the two walls when they are up). Then you would not need help to raise them.

Truth

I actually want this wall to bear some of the load just to avoid any possible sagging due to the weight of sheetrock. Garage has been standing for 30 years and I attached 1x8" ledger board vertically to the ceiling joist and rafter 4' from center. This still leaves an 8' foot span and I would like to store some items in the attic and wanted the wall to divide the room in between the largest span.

abracaboom

Ledgers are always horizontal, I think you mean side posts. Having the plates (or the walls) be in one or two pieces will make no difference as far as how much weight you can store in the attic. If you put A LOT of weight up there, what might happen is that your concrete slab cracks, but I don't think that's your plan.

mae-ling

If this wall is truely load bearing then it is another matter.
What is the distance between this wall and the other wall?