Stud Depth for Finished Basement
Hi folks — I’m in the planning phases of finishing our basement (my city follows 2018 IRC), and to maximize space I’m considering using 2″x 2″ studs to frame out the drywall along the exterior poured concrete basement wall to maximize interior space. My thought is to use closed-cell spray foam against the poured concrete basement foundation walls to get the required 10/13 r-value for insulation (should be about 1.5″ of spray foam depth), and this also gives me a moisture barrier. The plan is to frame about an inch away from the concrete, and then spray foam between the two so I don’t have studs up against concrete (treated lumber for the bottom board of the frame wall).
My question is, what are the disadvantages of using a thinner board like a 2″ x 2″ instead of the standard 2″ x 4″ stud depth for this exterior drywall wall? Can still use traditional 2″ x 4″ for the interior basement walls, but seems like a good way to reclaim some square footage using shallower studs along the concrete wall. Any advice would be greatly appreciated!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
2x2 are too wonky for framing, you can however use 2x3. 2x3s also give you enough space for standard device boxes.
Some people people use 1 5/8" metal studs but they come with their own complication with wiring and mounting things like shelving down the road. I would stick to wood.
Appreciate it, not going to figure out metal studs this time around, and will keep away from the 2"x2"s but will look into 2"x3"s, somehow forgot they existed in all this planning
argonbach,
The only circumstance when 2"x2"s make sense as studs is when they are affixed directly to a wall - where they are really better described as furring. You can't get two nails into the ends without splitting them.
As Akos said, 2"x3"s work, but whether it's work using them over 2" x4"s just to save an inch is an open question.
Thanks this is helpful, these would be on the exterior walls and "affixed" via the spray foam that would connect the framing to the concrete wall. But will definitely stay away from the idea of using the 2"x2"s to frame out
Both wood or steel studs work.
I actually prefer 1.625" steel studs for this application. If you want a straight wall, steel studs are are flawless, fast and practical. No time is spent sighting and culling, you can batch cut them, you simply screw them together with self drilling screws, as opposed to predrilling and screwing wood or worrying about splits with a nail gun. holes are already there for electrical, etc. Since you're planning to be an inch off the wall, that'll leave you room for 2.5" depth electrical boxes.
The only factor with steel studs is wall stiffness. After drywalling with just straight studs, the wall will flex quite a bit. Adding cross bracing and L brackets bracing against the concrete wall stiffens it . But in this case, since you're CC spray foaming, that'll tie everything together and stiffen the whole assembly. I'd probably still throw L brackets in case of some overzealous spraying might push the wall out of plumb.
They're also fine for mounting things like shelves, I usually use fine thread screws for this, instead of wood screws. Same considerations for wall stiffness applies for mounting things like shelves. But don't let their individual floppyness fool you, once the whole assembly is in place and tied together, its a good wall that saves space and allows for more insulation.
Just my experience,
Jamie
Went ahead and bought the lumber for this yesterday, found some 2"x3" 8' stud boards which will be cut down to the ~7'4" basement ceiling height and then plan to rip the Pressure Treated 2"x4" down to 2"x3" for the bottom plates of the stud wall. Thanks again for the help!