Finishing a basement is one of those ideal flipper moves to create extra livable square footage in a home, and knowing how to frame basement walls is the first step in the process. If you’ve framed a shed or another above-ground space, you are a little bit ahead. But, there’s still some nuance to basement wall framing.
Tips for Accuracy, Working Alone, Code Stuff DIYers Ignore
I can’t tell you how many DIY Facebook group posts I’ve seen of dudes beaming that they just slapped up a basement wall, claiming something like, “I framed my basement!” And while it’s true they did, it’s also abundantly true they not only didn’t get a permit, they don’t know how to get a permit. And framing a basement is a permit-y kind of job.
I’m not trying to be snarky, but something screwed to the floor of your home seems like something that should be done correctly. Maybe I’m off my rocker. Anyway, here are a few carpentry, code, and workflow tips I use or follow when I frame basements.
Layout and bottom plate
First, I don’t “tip” walls framing a basement, meaning I don’t build the on the floor and tip them into place as a single unit, like how a new home is framed. Some people do, but in the houses I work on, it’s sooooo not worth it. Ceiling pipes, lumpy old slabs, beams, HVAC trunks…forget it. Slow is fast here for me. Way more accurate and way fewer mistakes. To put a finer point on it, if you need a sledgehammer to bash your wall into place, you’re doing it wrong.
I use a rotary laser to establish a line describing the front of the plates and studs. The layout cue I’m working from is that I want the back of the studs–the side facing the foundation–to have 1-inch between the two surfaces. I then snap lines and set plates.
Code wants the bottom plate to be pressure treated lumber. I use a rotary hammer and Spax #10 x 3-inch Multi-Material Screws to set the plate on the line.
Fire blocking
Next, “fire stop” or “fire blocking”. The name is really a misnomer. It should be Fire-Slower-Downer. All it is is a barrier to hold any fire that begins in the basement for a little longer so people have time to react and get out. The firestorm that is a flames being sucked through unblocked framing is impossible to describe.
All fire stop is is a sheet of 1/2-inch OSB or drywall nailed to the framing above the stud wall. I set it 1/2-inch back from the chalk line so I can see it later for installing the top plate. And by “nailed” I mean “stapled.” I love my narrow crown stapler for this job.
Top plate
Next, the top plate goes in. To assist me when working alone, I make “hooks” out of 2-by stock or furring strips. It’s a third hand kind of thing.
Then I set a stud on the left side–nice and plumb!
From there I pull my layout.
Installation of studs
Concrete slabs are lumpy. Lumpy enough that all the studs aren’t the same length. Maybe I’m too persnickety, but I want all the studs to fit between the plates.
Side note, I love this Skilsaw sidewinder. Fast, durable, affordable, beastly. There’s a blade-left version, too.
I’m also impatient, so I stack a bunch on my Werner rolling scaffold (it’s a Werner; I love this thing) and measure, cut, place. Roll, rinse repeat.
Code and Fire Stop Notes
The basement shown here had a vapor barrier already installed by the builder, awesome. If you’re working on a home that doesn’t have a vapor barrier–and you need one–I install it after the fire stop. Where I work, it’s simple: A drape of 6mm plastic fastened to the fire stop that hangs to the floor.
This basement required a vertical fire stop every 10-feet between the studs and the foundation. That was easily done by packing Rockwool insulation–my total fave for all insulation–behind the stud.
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