Can furring strips be installed diretly to a cinderblock wall not in a basement?

Question

I've tried finding a definitive answer but it's far more common for folks to have block walls in basements that need to be furred out, so the information deals primarily with that and I believe this is different.

Problem:

The original owner of the home I just purchased used a combination of 1/2" and 3/4" high-grade plywood as wall coverings. Some of it was furred out to accommodate a pocket door and electricity, but the entire section of the perimeter (exterior) cinderblock wall has the wood nailed/glued directly to it. The wood has no signs of water damage of any kind and the wall's exterior has vinyl siding.

Plans:

Ultimately I want to go with drywall. I plan to install furring strips to attach the drywall to. Originally I looked into the $.99 - 1x2s for price and space saving, but I imagine I'll break half of them when I start screwing the board up. Same goes for the 2x2. In addition, they aren't treated, but neither are the 1x3 strips I've seen being recommended (again in a different context).

I'm now thinking of using pressure treated 2x4s mounted wide-side-down just for piece of mind and plenty of space for shallow j-boxes. I would mount them 24" on center with either tap-cons or ramset. I plan to have the assembly entirely held by the wall.

Question?

Are there any moisture considerations when mounting furring strips to a cinderblock wall not in a basement but with an exterior side?

I've read it's always an issue mounting untreated wood to concrete or other porous material, but he amount of time - about 25 years - and the lack of damage make me question this.

Are there any other processes that can be used to accomplish this if it is a problem (i.e.; sealing the wall, painting the wood with a special product, etc.)?

Answer 1

This is related to your question, but something I felt like commenting on: since your CMU exterior walls are covered up with vinyl siding, you have a perfect opportunity to insulate your house, which should give you quite a lot of bang for buck given that it currently has none. Remove the vinyl siding (carefully), cover the CMUs with 3+ inches of rigid foam or mineral wool boards, and then re-install the siding right over that. The difference in comfort and utility bills should be dramatic.

Answer 2

You need to decide what you are hanging the drywall on.

Choices:

1. Ramset framing members of whatever depth and economy you want to the concrete block. I'd be careful with ramset and concrete block. Light load shells perhaps. Tapconning on all those framing members seems expensive to me. I believe this is your main suggestion.
2. Adhesive framing members to the concrete block. I wouldn't recommend this. You could have trouble getting a good bond and glue lifespans for the cheap stuff can be very disappointing.
3. Build a standalone wall (I think this is what DMoore is suggesting) with a top and bottom plate and 'studs'. The studs could be 2x2s, 2x3s, 2x4s, etc.

Considerations:

1. Really? You don't want to slip even a 1/2" of poly iso foam board into this system. R-value has diminishing return but when you have nothing, the ROI is great (if you spend money to heat or cool the structure)
2. What climate are you in? It may be desirable to try to prevent interior vapor (is there a shower? cooking facilities?) from entering the wall system. I'd suggest you look at new smart vapor barriers but I'm guessing they are outside your project budget at ~$0.50/sf.
3. In my area (CO), 2x2s and 1x anything less than 4 is garbage lumber and not actually priced that attractively. Here, 2x3s and 2x4s are far and away the best values.
4. The problem with 2x framing members sideways is that you will be very close to 1.5" in thickness and your minimum thickness 4" square electrical boxes are 1.5" thick. You can obviously deal with via paper drywall shims or redwood lath strip pin nailed onto the 2x.
5. If you go with 1x material, how would you put electrical boxes in the wall?

Answer 3

Here in Arizona many older homes are built of cinder block, often just painted inside and out, no framing, no drywall, no insulation. This comes from an era when running a swamp cooler in the summer was cheap, and a gas furnace or electric heat in the brief winters was also cheap. Some of the older homes were PANELED on the inside, probably not a great idea for fire code. I've seen these drywalled over, typically the firring strips are used, and 1/2" drywall is attached over them with 3/4" screws. Any existing outlets, etc. in the block are left in place (typically they're metal) and an extension is added (slipped in place over the drywall, into the box) and new outlets installed with longer screws to hold both the new outlets and the extension box to the old box. It's best to have some of the firring strips near/around the box even if not secured to the block, to prevent movement when the outlet is installed. As someone noted, thin foam insulation is better than none at all, it will slip between the block and drywall. Be sure to install the drywall 1/2" up from the floor, and add a footer for baseboard using the same firring strips, and when it's time, use much smaller nails for that than you normally would.