# Insulating shop with cinder block walls?



## 12point (Jun 25, 2009)

Alright let me first say i have never done any structure work to a house besides putting up vinyl siding…, that is why i am asking you all this to better inform me on the steps i should take. I recently bought a house 3 or 4 months ago with a detached garage that is pretty much my shop. It measures 20×30 with a half bath. The shop and the house was built new 4 years ago. The walls are made of cinder blocks. The previous owner did not have insulation put up. In fact there is nothing up just the walls and the rafters on the ceiling. My question is if i were to try and insulate this shop what are the steps i should take? I dotn want an insane amount of insulation just enough to keep it bearable during the summer and winter. (i live in Ga, its 110 today). Ive been doing some research and it seems like i would need to put Rigid foam insulation against the walls and then frame in the walls with 2×4's and dry wall? And when i was watching a show on DIY the other night they put the rigid foam, framed in with 2×4's and then put roll insulation between the studs, and then drywalled it in. Any help is appreciated. Bear with me!


----------



## 33706 (Mar 5, 2008)

You might want to cross-post this one at the 'HomeRefurbers' site; just scroll down this page and click on the logo. You're already registered there!


----------



## Knothead62 (Apr 17, 2010)

If you put roll insulation between studs, staple the side tabs to the 2X4's to keep them from settling. Learned this from a veteran carpenter.


----------



## spclPatrolGroup (Jun 23, 2010)

Skip the spray foam, its not very effieceint, which is why you dont see nearly as much of it the farther north you go. Probably the best bang for your buck, use fiberglass. You want ot make sure you put a moisture barrier on both sides of the insulation, once between teh cinder blocks and the wall, and one between teh wall and the sheetrock. Most insulation is made to fit snugly between two studs so I dont think you need to staple it, just make sure you snug it up to the top before sealing it between the moisture barriers.


----------



## Sailor (Jun 17, 2009)

Either of the two options would work. I would definately put up 2×4's at least every 2' along the walls with a top and bottom plate, make sure your bottom plate (the 2×4 on the bottom of the wall laying flat on the slab) is a treated board.

I don't really see a need for the rigid insulation. I would just build walls inside of the block walls. Build them on the floor and then stand them up and nail the top plate to the trusses and put some hard nails (concrete nails) through your treated bottom plate into your slab.

As for insulation, they make fiberglass roll insulation to fit inside of walls with studs on 16" centers and 24" centers. Pick witchever spacing you decide and staple it up. You MUST staple it up or it will certainly settle down to the bottom 3rd of the wall and not do much good. The insulation is made to fit snug between the studs, but that will not keep it from falling.

If you are not sure about 16" on center or the 24" on center studs, it doesn't really matter in your situation. When you have a load bearing wall, you need your studs on 16" centers. If they aren't load bearing it isn't mandatory to use 16" centers.

For a shop, I would suggest putting up some 1/2" or 5/8" project plywood rather than the sheetrock. You will be knocking holes in the sheetrock in no time. Plus you can hang some things on plywood walls without finding a stud.


----------



## NBeener (Sep 16, 2009)

This …. like woodworking … is an area where I have more "book knowledge" than real knowledge, but … one thing to consider … is that you can use 2x*6* studs, and get 50% more insulation in there (may or my not equate to 50% higher R-Value. Didn't check).

If you live in a pretty harsh climate, it might make a big difference for not a WHOLE heap more money.

Of course … you eat up a LITTLE more space, but ….


----------



## 12point (Jun 25, 2009)

Thanks guys for the info. I will try to post this at the home refurbishers site as well


----------



## nailbanger2 (Oct 17, 2009)

One thing I haven't seen covered, is the fact that you don't need 2×4 walls on the inside. The reason I say this is your statement that you don't need that much insulation. Let me explain further. In Florida we use 3/4 rigid insulation directly against the block, then nail 1×4 PT verticals over this. Top and bottom 1×4s are preferable, but not necessary. Some cheaper builders use 1×2 furring strips instead. Drywall is hung on the furring giving a dead air space between them. You won't get a lot of R value, but you will save money. Remember, in Fla. we only have to deal with the heat, and most of that comes through the roof.

It's your money, and I don't know how cold it gets in Ga. Good luck!


----------



## KnotWright (Nov 6, 2008)

One thing we haven't discussed is your roof/ceiling. If 4 years ago the builder did not use the foil backed sheathing, you can get this sprayed on by most any insulation company. Since its 110 degrees there you'll really appreciate this reflective spray on stuff. It reduces the amount of heat transferred into the building. When I built my workshop in Austin, the price for the foil backed 1/2 inch OSB wasn't that much more then regular plywood, so I went and installed that. I was amazed at the difference that makes on how hot it gets inside the building. You can also buy rolls of this foil stuff and staple it to the rafters.

I too suggest using 1/2 plywood for your walls, you'll thank yourself for doing it many times over when you go to installing shelves and such. If you are in an area that "MIGHT" flood, you should consider drilling holes near the bottom of the plywood to allow any water to quickly drain from behind the walls in the event of flooding.


----------



## Dark_Lightning (Nov 20, 2009)

Check with you local Building & Safety people for their recommended levels of insulation for your area. Probably R29 insulation in the rafters, if you can get it in there. If you have a ceiling, you can have it blown in. This will block off most of the heat. Foam insulation has a higher r-value that fiberglass, and costs more. But it doesn't have the water issues you would see with 'glass- it doesn't soak it up. If you have a metal roof, you can staple radiant barrier film to the bottoms of the rafters, if you have a ridge vent. That would help, if you don't want to lay in fiberglass. There are new insulation products out there, one which is in a plastic bag when you put it up (I think it's fiberglass, but I'm not sure). This avoids the itch, and also provides a moisture barrier.


----------



## closetguy (Sep 29, 2007)

I also live in Georgia. I recently did a basement remodel that had cinder block walls. I waterproofed the walls, framed with 2×4s, installed fiberglass insulation, and nailed up drywall. Actually, I did stone veneer on one wall and drywall on the other three. With our humidity, and if you air condition the shop, you will need some form of moisture protection, or you'll end up with a nasty mold problem down the road.

Don't mess with the spray foam. It's messy and I question its insulation properties. It's good for hard to reach or oddball shaped areas.


----------



## MarkwithaK (Sep 12, 2009)

*"....if you air condition the shop, you will need some form of moisture protection, or you'll end up with a nasty mold problem down the road."*

Typically if you have a conditioned space and you are getting moisture/mold then the unit is over sized for the square footage.


----------



## 12point (Jun 25, 2009)

Closetguy…you live in georgia so you kinda know the conditions here$ - live in middle /south gammmyou mentioined I would need a good moisture protection …what would you reccomend?


----------



## NBeener (Sep 16, 2009)

"Typically if you have a conditioned space and you are getting moisture/mold then the unit is over sized for the square footage."

Very true.

To explain a bit more … people who want "a REALLY BIG a/c unit" ... don't understand: if it has "too many BTUs" cooling capacity for the space (and all the factors that drive heating and cooling calcs), then it will cycle TOO INFREQUENTLY, giving the unit NO time to remove the humidity from the air.

Good info about framing out a basement, and vapor barriers, in the SE, can be found here.


----------



## nailbanger2 (Oct 17, 2009)

All this talk about basements is interesting, as there are very few in Fl., but the OP says he's got a detached garage.


----------



## NBeener (Sep 16, 2009)

D'OH !!!!

Thanks, *nailbanger* ;-)


----------



## Gregn (Mar 26, 2010)

If you can get a hose in the block from the top of the wall. Git Styrofoam blown insulation and insulate the inside of the block with it. You can generally rent the machine to blow the insulation with. If your concerned with moisture on the block walls seal them with DRI-LOC . Just my 2 cents worth.


----------



## jusfine (May 22, 2010)

Perhaps there is some confusion between rigid insulation and spray on insulation.

Two entirely different things.
Rigid comes in sheets (2'x8') SM is the brand we have here and provides a continuous insulated barrier as nailbanger has already mentioned.

If there is not much more required than R8, to save space, you could install plywood right over the rigid sheets. Sounds like insulating the roof and/or ceiling is going to be more important where you live.

If you can fill the blocks with vermiculite or similar insulating material, it will add to your insulation value. Over time that type of insulation does settle, so I would use the rigid as well.

Here I have R40 batt insulation in the ceiling of my shop, but we also get -40 degree winters…

All the best with your project!


----------



## nailbanger2 (Oct 17, 2009)

*NBeener*, you crack me up! Thanks for the morning chuckle.


----------



## 12point (Jun 25, 2009)

I would rather not do the spray on insulation because of the price. As far as AC goes… i would have a window unit most likely not central heat and air.


----------



## 12point (Jun 25, 2009)

NBeener….thanks for the link. THere is some good info on there!


----------



## Bluepine38 (Dec 14, 2009)

You have not mentioned electrical wiring. If you are going to wire through the wall, make sure you have 
enough plugins, and you never can have too many, you are always moving a piece of equipment. A power
pole, or some type of electrical outlet from the ceiling will help for a centrally located table saw or workbench
will keep you from tripping over extension cords. Try drawing out a few trial layouts for your shop tools ahead
of time and it will help you layout your wiring. Check your local building codes, you can save yourself a bunch
of money if you have the knowhow and they will let you do your own wiring. If you have to have it done
professionally, having the outlets and lighting ideas and switches planned ahead of time will help also. Good 
luck. Please plan on an outlet for a dust collection system of some type, it will save some lung problems.


----------



## NBeener (Sep 16, 2009)

*Gus* makes some great points, about overall shop design.

Grizzly has an online shop layout gizmo.

Quite a few books address the subject well. It might be worth buying one of those books-example to make sure you've thought through all the important bits … LIKE electrical, lighting, dust collection, machine placement, operational flow, storage, etc., etc.

One of the greatest things about a new shop is … that it's a clean slate.

Have fun ! Keep us in the loop with pictures, huh ?


----------



## 12point (Jun 25, 2009)

The shop is already wired for electricity and all…how much trouble is it dealing with that aspect of it when insulation and putting up the wall etc?


----------



## jusfine (May 22, 2010)

If you have wiring on the walls (likely in conduit), you should be able to extend the boxes with what is commonly known as plaster rings or extensions to accomodate the additional thickness of the new wall, and hopefully the electrician has left enough slack in the box when they wired it up…


----------



## 12point (Jun 25, 2009)

jusfine…thanks for the info…now that you mention it i believe their is conduit.


----------

