Basement Framing Issues Prep for Drywall

golddog

I've framed my basement w/2x4 floating walls and passed all my rough inspections. My poured concrete foundation wall corners weren't 90 degrees, the walls weren't plumb, and the floors and joists weren't level. Nothing dramatic - well within the tolerance of modern cookie-cutter houses from what I'm told - but it was a bit like trying to frame a square cube inside a Bucky Ball, all in a climate that has zero humidity and can twist a fresh piece of lumber in to a pretzel inside of 24 hours.

Before I put the insulation and ultimately the drywall up, I want to even out the plane of each wall, either by adding cardboard shims, or planing the studs down. The two walls of concern (16' & 14') meet in a 90 corner w/an egress window on each. The top and bottom plates in the corner are actually 90, but for various reasons (mechanical, structural, space) the walls couldn't be built in one piece. Got 'em as straight as I could but especially around the window boxes some of the studs throw off the plane of the wall by as much as 3/8" either in or out compared to the plane and effectively make the wall not square over the entire span even though major sections of it are fine at various heights.

I feel like the windows will make any irregularities super obvious once the drywall goes up. Part of me wants to just do minor adjustments now and then do ad hoc shims/shaves during drywall. I'm thinking an 8'x4' piece of sheetrock will be a better practical guide than a 4' level.

So any advice for a handy amateur on the best way to go about prepping these walls? Any suggestions/red flags/advice much appreciated.

Bob Mariani

Well you made it hard on yourself by making common mistakes to start with. Each stud has a crown. All the crowns should be set in the same direction. this keeps the wall from looking wavy. Any excess crowns should have not been used. Seems you did not go to a lumber store to buy your studs. Did you verify the studs were dry enough to be used?

Using a laser will make fixing this easier. Just set your bottom plate straight and square. Level the top plate to sole plate. (Which should be on a sill insulation and pressure treated wood) Now from a corner using the laser shim each stud as needed with drywall shim stock or custom shims ripped from a table saw. Fixing this now will be worth the time. Much easier to tape drywall when the installation is correct to start with.

golddog

In thinking about my OP, I probably didn't do it justice in explaining it. Sure there's some minor stud bowing here and there but I was meticulous on picking and using acclimatized straight wood (from a good, local lumber store) and making sure the crowns, to the extent they existed, all faced the same way. You should see my reject pile.

Because I had to do the walls in sections, and couldn't really build them "in place" b/c they needed to float, it's the spots where they join (which coincidentally are where the poured in walls get goofy) that are the main issue and magnify little trouble spots.

If I start from the corner w/the windows (where the top and bottom plates are 90), by the time I get to the end of the wall I'm 3/8" off square b/c the "connection" wasn't exactly in plane and I need to shave. If I start from the end of the wall and work toward the corner, I've got a 3/8" gap. So I guess what I'm asking is, what's the lesser evil here - shaving 3/8" off the studs at the end, or adding 3/8" at the corner? Or trying to combo add/shave 3/16" between the two ends?

I think I'm leaning toward using the window corner as the anchor since visually that element is so obvious. I had thought about the laser - I have a 1' hand held 3-way laser level but I need to double check the accuracy over that length or get something beefier.

Bob Mariani

your hand held should be acurate enough for this project. I would suggest the shims and not cutting down the studs. Are these studs against the concrete? They should be at least 1/2" off the 2" required rigid foam insulation against the wall.

Willie T

I really couldn't make heads nor tails out of your explanation. But HERE is an easy way to fix bowed studs... either bowed in or out.

__________________
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Willie T

golddog

Yeah instinctively I hate to shave the studs. These are the first floating walls I've framed and I was trying to make them square, plumb, etc to compensate for the F'd up foundation walls. They're generally a good 1/2" off the wall but sometimes they're just a hair off (but not touching) the foundation wall, sometimes more than a 1/2". No rigid foam in the equation (code calls for a different scheme here).

Bob Mariani

Unfortunately the codes have not kept up with the latest science and as such you will be building a wall guaranteed to fail. Example: Warm air moves into this wall and hits the cold foundation wall. It condenses.... what are you doing to stop this and what are you doing to remove this moisture.

golddog

The latest science doesn't seem to have much consensus around best practices for vapor barriers. I actually wanted to do XPS or something of the sort, except I couldn't get enough R value out of it to meet code within a reasonable thickness.

I'm no contractor, but I'm pretty good at research. The exterior is sealed up pretty well, and I Drylocked the entire interior. The main concern in this region is expansive soils and capillary action during that once in a decade rain storm, which the above addresses.

Winters get cold but relative humidity stays low and condensation is a relatively low risk in basements here. The insulation is kraft faced batts w/MR drywall and that's it. No vinyl. For every one person who says put the vinyl here or there, I could find a person who says the cutting edge science is that vapor barriers actually cause more problems than they solve; that some condensation is inevitable no matter which way you go, and that it's better to give it a way for moisture to evaporate (rather than trap it behind the sheet). My entire building department and some people I talked to in the biz all agree.

Just for laughs b/c I'm curious about it, I'm going to install some sensors behind the framing so I can check on moisture levels from time to time under various conditions. Plus I saved up a bunch of desiccant packets from various packages...couldn't hurt to throw those in there too :-)

Bob Mariani

But this is what I was trying to say. Most research indicates that a poly vapor barrier for you climate will cause more problems than not. yet many building departments are still asking for the vapor barrier on the warm side. This is causing many failures in USA. But a vapor retarder (kraft faced insulation and/or latex paint) should be all that is needed.