If you seal the bays with plastic, you could do blow in insulation.

I'm not opposed to it, but that does sound a bit complicated and expensive. I'm looking to see if I can insulate this 1 wall for about $100 or less

Insulation is hard to do nowadays less than a 100. Might get foam board and cut it down.

I was thinking about that too

Lowes carries a 24" R19 wall insulation that covers about 133sq ft. It's $109 here. Yes there are some rolls you can get for $30, but they only cover 40sq ft.

That's for 2x6 studs, though, and won't properly fit in a 3" cavity.

A serrated knife cuts it well. Or, Home Depot has some pink board with perforated lines to allow for easy sections.

A general rule of thumb with insulation - either board or glasswool roll - is there is incredibly little waste. Just cut to size and put it in the gaps as best you can. I'm assuming you're going to be covering with a vapour barrier and plasterboard / drywall in any case? It doesn't matter a damn how the insulation looks - as long as it's full coverage with as close to no gaps as possible.

If you get rolls of insulation for the required area just cut to the required width (in your case 22") with a saw - while it's still in the roll. Sheet insulation can be like the worst made jigsaw in the world - who cares? It's going to be hidden in any case. Just slice it all to fit nice and tightly to the studs.

6 divided by 2 is 3. Batt insulation splits very easily.

The R13 is for 2x4s and covers 163sq ft for $118 Item 108995.

You can find insulation that is 24” wide. It’s commonly used. Using 3-1/2” thick insulation will be fine. Compressing the insulation makes it lose a little bit of R-Value, but not much.

2x3 exterior wall framing? Is this infill in a timber frame, pole barn, or something similar? Knowing what kind of structure this is would be helpful in recommending an insulation strategy.

Rigid insulation will fit that bill.

Who is Jon?

It's a wall in a basement laundry room. The wall is a concrete foundation wall that has some 2x3 framing on it already

I bought 2” foam board insulation with a r-10 rating last week, 4x8 sheet was $42

I do r13, so mine was 55.

Just buy the bat insulation for 2x6 walls and pull it in 1/2. It generally separates very cleanly along a cosistent plane. It does create a little more airbourne dust than cutting, but i would recommend wearing a proper ½ mask respirator anyway.

Buy rigid insulation, cut it to fit and glue it in. Finish it off by using spray foam on the sides top and bottom to fill gaps.

Personally, I’d take the framing (really furring) out first. Make sure there are no leaks in the wall or walls, and if there are you have to fix those before you think about insulating. For insulation, rigid foam right against the foundation to cut off thermal bridging. Foam thickness depends on climate zone and insulation type (eps, xps, polyiso, phenolic). Then reinstall the furring and fasten your drywall to that.

IMO, furr out the 2x3 to turn it into 2x4s and then put a 2x4 in the 24 inch space so you have one 16 inch on center stud and another 8 inch on center.

That way at least half the space will be easy to insulate

The 23 inch wide insulation is like 20 cents more expensive per sqft so depending on size it could be cheaper to create some 16 inch on center studs

This is the best insulation answer. Lots of work

Are your studs 2" x 3" or 1.5" x 2.5"?

it increases R value per inch, but loses inches. The R value actually goes up when compressing fiberglass.

Are the spaces 24” or are the studs 24” on centre? You should be able to find fibreglass batts that work for 24 on centre.

As far as the depth of the studs goes, can you move the framing out? Pull the nails top and bottom and move it out from the wall 3”. That'll give you plenty of room for insulation. I'm assuming that the framing isn’t structural—just backing for drywall.

It’s more labor, but they would fit. Run them crosswise rather than up and down.

I've been pricing things out and you are right. I think I'm going to do rigid foam and just cut it to size around the framing and used spray foam for any gaps.. I have about 88 sq. ft and the price is around $224 for 2in....What do you think about 1 1/2 inch?

It's not a load bearing wall, but the studs are tapcon to the concrete wall. The spaces are 24" on centre. I found some, they're just a lot more expensive

That's a good idea

Since I don't know the temperatures around your parts, I would be looking at the R values. But, 1 1/2 board does a decent job.

They are nominal 1.5 x 2.5

They weren’t fooling around. But, bare wood against concrete may start to rot. If your foundation isn’t damp-proofed and we’ll drained.

Use R8 batts for 2.5" walls and cross cut them. How many square feet of walls do you have?

Compressing the insulation reduces its R-value considerably.

I would use rigid foam board, take your time and cut to fit, and use a spray foam gap sealer (comes in a can) around the edges once it’s in.

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Use rigid foam insulation. It comes in 4x8 sheets. It will perform way better than any batt.

Make sure you cut the insulation about 1/4" short on all sides. That will leave a nice gap to fit the spray foam in.

88

I'm in Missouri so Temps can get cold to hot

What do you mean run them crosswise?

So the studs are nailed to the concrete wall. What do you recommend to take them out?

Can I not add pictures to post here? I can't seem to find the option

Batts are usually run up/down, run them side to side. 24” long, as many as you need to fill the cavity. You can peel 6” batts in half, if that’s what you’re working with, to fill your 3” deep wall cavity.

A hammer and a big flat bar or something similar should work. Even a big flat shovel or floor scraper - whatever you have that you can hammer into the joint between the wall and the stud. Start at an end - top or bottom - and work to the other end. If the nails pull through the studs, no big deal. You can use vise grip pliers to kind of twist the nails back and forth until they loosen, or if you don’t have those, just tap the exposed nail back and forth with a hammer until they fall out or break off.

Ok so it wont take much longer to do with cross cut R8 batts.