Insulating Block Walls

[AJ1978]

I have the back section of the shop that is currently unheated, but will begin to use it again.
Outside walls are BLOCK.
I was thinking, some kind of foam board against block
2x4 or 2x6 framing 24 OC and then finish cover. Either Plywood or drywall

eventually will keep some heat here as needed.


Ideas, or suggestions

 

[matt_i]

I'd want to damp proof the block with some sort of paint-type stuff...like one would use in a basement on the inside, if the outside wasn't really done very well.

I think you will find that fiberglass rolled will be cheaper than the foamboard.

 

[tms0425]

I have the back section of the shop that is currently unheated, but will begin to use it again.
Outside walls are BLOCK.
I was thinking, some kind of foam board against block
2x4 or 2x6 framing 24 OC and then finish cover. Either Plywood or drywall

eventually will keep some heat here as needed.


Ideas, or suggestions

I've used InsoFast which has both 2" foam and plastic studs at 16 OC. It worked great and was really easy. I put LP Smartside T1-11 4x10'x3/8" panels up over the InsoFast.

See my post HERE

 

[Chris705]

Another option is to use 1-1/2" or 2" foam board and fasten it to the block w/ appropriate sized metal "z" furring strips run horizontally. Tapcon screws hold the furring in place, then you fasten drywall or wood sheathing to other leg of "z".

 

[rayra]

I'd want to damp proof the block with some sort of paint-type stuff...like one would use in a basement on the inside, if the outside wasn't really done very well.

I think you will find that fiberglass rolled will be cheaper than the foamboard.

Cheaper and more R value. Stuff comes a lot of ways / dimensions. Buy it to fit yoru stud spacing, unless you feel like doing a lot of cutting (which is relatively easy.

2" rigid foam board is R-13, but nearly a $1/sq' in area. Figure $2.50/sq' to fully stuff a 2x6 cavity. Call it R-33.
R-19 fiberglass batts 24"x48", 119sq' to a $68 bag, about 57cents/sq'

So about 4x the cost to get 60% more R value in the same framed space.

Don't try to stuff R-30 fiberglass in there, it supposed to be in a 9-10" deep space. Stuff it in a 5-1/2" thick wall and you hinder its effectiveness. I don't know to what degree though. You might stuff R-30 in there and get better than R-19 value despite being compressed. But you'll be fighting it during the install, too.


eta - keep in mind too that putting such large framing in is going to eat into your useable space. But if you want to run air lines and extra outlets, it might be worth it.

Or use a 2x4 wall, stuff it with R-13 fiberglass, for about 47cents/sq'. So a 2x6 wall, stuffed, will cost you about 60% more than a 2x4 wall

 

[p_mori7]

Hang a plastic vapor barrier down along your block wall. Let it run about 4' longer than the wall is tall. Frame out your 2x4 studwall, about 1/2" away from the block wall. The bottom plate of your stud wall should sit on the vapor barrier that you let run longer. Insulate the stud cavities with R13 fiberglass bats. Run the excess 4' of vapor barrier back up the front side of the studs. Apply interior sheathing (wallboard / OSB / plywood, etc).

 

[NUTTSGT]

I tapconned 2x4s flat to my block wall, put in some 1 1/2 EPS "white styrofoam" between them and covered it with OSB.

 

[schmelpboy]

I just finished doing 3 inch foam board that has an R-19. Of course, I have a buddy that runs an insulation company. Gas company gives 1,000 rebate on my job, which came out to 300 bucks out of pocket. That's me doing no work at all, and 3 inch foam board.
I, too, have block wall. I painted over it with that really heavy duty paint (I can't remember what it's called) that's made for keeping water out, or keeping the walls from seeping. Then, I had my buddy come in last week and install the 3 inch. I'll start my 2x4 construction this week, then greenboard over it.

 

[trainer]

Hang a plastic vapor barrier down along your block wall. Let it run about 4' longer than the wall is tall. Frame out your 2x4 studwall, about 1/2" away from the block wall. The bottom plate of your stud wall should sit on the vapor barrier that you let run longer. Insulate the stud cavities with R13 fiberglass bats. Run the excess 4' of vapor barrier back up the front side of the studs. Apply interior sheathing (wallboard / OSB / plywood, etc).

I think this would be asking for trouble. You want to have the vapor barrier on the warm side of the insulation.
You may be able to use something that breathes like tyvek between the studs and the block and poly between the insulation and interior sheeting.

 

[raddksn]

Not trying to hijack this, but I'm thinking about z-furring and riged foam vertical on the outside of my 25x30 block garage. Then hang vinyl siding to match the house. Anyone see a broblem with insulating the outside?

 

[dutchgray]

Insulating on the outside of masonry is done all the time over here, on houses built before the requirement for insulation, they usually mesh and render it

 

[kbs2244]

Insulating and siding on the outside of a block wall is the preferred method.
The idea is that the "thermal mass" of the block will absorb the heat if inside the insulation and then reradiate that heat as the room cools.
You get fewer and less extreme temp swings.
You have a real "man cave."

 

[raddksn]

Insulating and siding on the outside of a block wall is the preferred method.
The idea is that the "thermal mass" of the block will absorb the heat if inside the insulation and then reradiate that heat as the room cools.
You get fewer and less extreme temp swings.
You have a real "man cave."

Thanks, that's exactly the reply I was hoping for. My two cents worth for the op why give up space inside if you can insulate on the outside?

 

[AldeanFan]

I have a block wall garage and I had planned to insulate on the outside with foam but the heating costs really are not too bad. My gas bill went up about $200 per year after I put in the big max. (R20 ceiling). You just have to keep the temp constant, don't just heat when you're in the garage, it takes too much energy to heat up those cold blocks but once they're warm they stay warm


Sent from my iPad using Tapatalk

 

[AJ1978]

Thanks Guys, sounds great. The building is about 40 wide, and the way the beams columns are set I could Stud out the wall. I am most aware of packing insulation and the negative effects of it.

I will gladly give up a bit of space on the walls to keep the place warmer. I think It will clean up the look.

I am intending on turning this area into a detailing bay, and while most work will be in the summer I am expecting some in the winter. The ceiling is a whole other issue, but one step at a time. Its closed off and that's what is important.

So are we suggesting vapor barrier, then foam board then studs and fiberglass? I will be re-reading shortly

 

[WNYflyer]

I have the back section of the shop that is currently unheated, but will begin to use it again.
Outside walls are BLOCK.
I was thinking, some kind of foam board against block
2x4 or 2x6 framing 24 OC and then finish cover. Either Plywood or drywall

eventually will keep some heat here as needed.


Ideas, or suggestions

These should help though a lot of reading, Section 6 is energy

http://ncma-br.org/e-tek.asp

http://ncma-br.org/pdfs/83/TEK 06-11A2.pdf

http://ncma-br.org/pdfs/83/TEK 06-17B1.pdf

 

[NUTTSGT]

Thanks, that's exactly the reply I was hoping for. My two cents worth for the op why give up space inside if you can insulate on the outside?

I also did the outside of mine with firring strips, 3/4" EPS, and covered that with foil faced OSB. I sided over that like the rest of the garage.

I did the inside first as I needed to get something on the walls as I was losing heat during the Winter. The cold *** walls wouold draw the heat right out of the garage. I couldn't do the outside as I still had plenty to do to it first.

 

[tms0425]

I also did the outside of mine with firring strips, 3/4" EPS, and covered that with foil faced OSB. I sided over that like the rest of the garage.

I did the inside first as I needed to get something on the walls as I was losing heat during the Winter. The cold *** walls wouold draw the heat right out of the garage. I couldn't do the outside as I still had plenty to do to it first.

Did you just tapcon the furring strips into the block? That seems like a ton of work. I'm about to do the outside of my block building, putting up LP Smartside 10'x4'x3/8" T1-11 panels and trying to figure out a strategy for attaching furring, sheathing and/or insulation, and T1-11 panels.

 

[bimmer1980]

I've used InsoFast which has both 2" foam and plastic studs at 16 OC. It worked great and was really easy. I put LP Smartside T1-11 4x10'x3/8" panels up over the InsoFast.

See my post HERE

I second this method!

To OP -- Definitely check out the INSOFAST website. If I was insulating a block wall, I would do this method for sure. I plan to use it in my basement when I get to that project.

My sister just did her basement and I had recommended using the INSOFAST foam panels. She ordered a sample, ran it by her contractor and they ended up using it. Sounds like it went well.

 

[fourjeepin]

Re: Home Depot Clearance Thread 2015

I tapconned 2x4s flat to my block wall, put in some 1 1/2 EPS "white styrofoam" between them and covered it with OSB.

How did you cut the foam? I planned to use the 2" purple foam sheets and just started attaching 2x4s. I know it will cut easily, but it seems like it would make a huge mess.

 

[NUTTSGT]

Did you just tapcon the furring strips into the block? That seems like a ton of work. I'm about to do the outside of my block building, putting up LP Smartside 10'x4'x3/8" T1-11 panels and trying to figure out a strategy for attaching furring, sheathing and/or insulation, and T1-11 panels.

Yes, I just tapconned the furring strips into the block. IIRC, I then screwed the OSB to the furring strips.

 

[NUTTSGT]

Re: Home Depot Clearance Thread 2015

How did you cut the foam? I planned to use the 2" purple foam sheets and just started attaching 2x4s. I know it will cut easily, but it seems like it would make a huge mess.

Being that stuff is EPS, I used an old steak knife, serrated blade. It did create a little bit of a mess. . . .little white styrofoam balls but it's easy to clean up. It'seven better if you can cut it outside.

 

[Iggi]

I have had excellent results keeping heat in by using radiant barrier. You can buy it rather inexpensively by 1000 sq ft at atticfoil.com. Does a great job of getting the hot texas summer out as well. great stuff.

 

[schmelpboy]

Sorry for the **** pic. But this is the 3" stuff on my walls in the basement.