Should single course of cinder block be insulated?

[GreenScrew]

In northern WI and my garage walls are sitting on a single course of cinder block and was wonder how much heat I'm losing and what my current options are to insulate if warranted? Would it be worth glueing 2" pink XPS foam board on the inside?

Also, the header to the garage the door is a large steel I-beam, any thoughts/idea about insulating that and/or how to finish the inside of it so it looks decent?

 

[DeltaWye]

Well an 8" concrete block has an R-value of about 1 or 2 whereas 2" of extruded polystyrene would be R-10, so yes, it would make a huge difference if you're heating the space. Besides the poor R-value, masonry also has a lot of thermal mass so if you let the garage get cold and then you run a small space heater to do some work in there, it takes forever for things to warm up, just like a cold concrete slab. Just bear in mind that foam is supposed to be covered up by something fire-resistant, so that adds cost and work beyond just putting the foam up.

edit: Sorry, I pictured this as an entire block wall, not just a single course of block at the bottom. Duh. So no, it wouldn't make a huge difference.

Don't know what to tell you about the beam other than put foam in where you can. Maybe see how much it is to have someone spray foam the whole garage.

 

[Firebrick43]

You could use synthetic stucco to cover it.

 

[Milton Shaw]

Synthetic stucco is a very soft material and would be torn up and look like **** fairly soon. What would look a lot better would be some bright tread plate bent to an L shape with a short final bend on the top to attach to the wooden base plate or studs higher up on top of the concrete block. Fully insulated and very attractive. You could even have a piece of 2" insulation on top of the block too.

 

[Randy in Maine]

My crawl space under my house is also a single layer of block.

I put 2" of the foil faced rigid foam on the inside and really helped. I drilled into it with Tapcon screws and used fender washers to hold the foam there securely.

Then I taped the joints with the foil tape.

If I were doing this to the inside of a garage, I would likely put metal siding of some sort on the inside to cover it all up.

 

[Jess]

I have a section in my mechanical room that is 2 rows of block above the finished floor. We insulated and isolated the floor, then added 2" of XPS over the block. A piece of Hardy panel glued to the foam and trimmed out on the top. So far, so good.

 

[DeltaWye]

One problem with foam I should have mentioned is that you don't have a good place to run electrical. Also, how are you going to mount things to the wall?

I think what I'd do is frame a wall of 2x3's, leaving a space between the studs and the block wall of about 1/2" to eliminate thermal bridging, run your electrical and anything else you want put in the walls, put blocking in if you're putting cabinets up and use batt insulation. It will be compressed 1/2" but that's not a big deal and you should get around R10-R12. Drywall, plywood or whatever you like for your final wall finish.

 

[bczygan]

One problem with foam I should have mentioned is that you don't have a good place to run electrical. Also, how are you going to mount things to the wall?

I think what I'd do is frame a wall of 2x3's, leaving a space between the studs and the block wall of about 1/2" to eliminate thermal bridging, run your electrical and anything else you want put in the walls, put blocking in if you're putting cabinets up and use batt insulation. It will be compressed 1/2" but that's not a big deal and you should get around R10-R12. Drywall, plywood or whatever you like for your final wall finish.

OP only has a single course of block, with his wall sitting on top of that.

Bill

 

[Know Wosad]

Its a sin to use block and not fill it. Drill it and fill it with concrete/cement.They actually make some aerosol foams to fill block but select it carefully. I bought a can one time and it expanded with such force it blew a 2x12 wood frame apart.Damn stuff quadrupled in volume as it set. It takes some force to bow apart a pressure treated 2x
I wish I had a pic. It was about a 10 foot long beam in my shower room. I formed it with the 2x and sprayed that **** instead of using cement. I hear this screeeeeetch and. Holy **** . A mess. I re-did it with cement
OH.
Here. This is with concrete....after

 

[The Cobbler]

virtually any insulation you add will help with heating. the overall heat loss on that area won't be huge tho.

 

[matt_i]

I wouldn't insulate it. Part of my existing shop is built as such. The 8" wide block is already considerably wider than even a 2x6 wall (5-1/2 + 1/2" sheathing+ 1/2" drywall), and adding another 2" of XPS is going to shrink the shop down by virtue of having to place things further away from the walls (or create nasty voids where things can get dropped down to never never land)

Being that heated air rises and the wall is pretty thick, I personally wouldn't go thru the trouble.

The XPS is probably a good solution for the web of the I-beam, better yet if you could get to the other side and insulate it also...

 

[DeltaWye]

OP only has a single course of block, with his wall sitting on top of that.

Bill

Not sure how I read single course as single thickness. Twice.

 

[bczygan]

Not sure how I read single course as single thickness. Twice.

Don't worry. I can misread AND misstate things much better than you!

I use the edit function on almost every post, hoping all the time that no one has quoted it yet!

Bill

 

[GreenScrew]

OP only has a single course of block, with his wall sitting on top of that.

Bill

That's correct. Sounds like not a huge issue. If I hadn't already insulated and sheetrocked the walls I'd probably take a look from top side to find out if they're filled and load them with vermiculite if not, but for now I'll leave it and look in to adding insulation to exterior in the spring.

Thanks for all the feedback!

 

[TractorJeff]

If you had stated that you had laid insulation and PEX tubing in the floor. Many more posters would have stated you need to put insulation in that one course to create a Thermal break! As the cold will migrate in and your heated slab would be cold on the edges all the time wasting Energy.
But seen as you only asked about one course of block you got different answers!
IN MY OPINION;
I would insulate it on the inside with a metal knee wall cover as suggested or preferably insulate on the outside down below the footer or edge of the concrete slab to lessen cold migration into the wall/slab.

 

[GreenScrew]

If you had stated that you had laid insulation and PEX tubing in the floor. Many more posters would have stated you need to put insulation in that one course to create a Thermal break! As the cold will migrate in and your heated slab would be cold on the edges all the time wasting Energy.
But seen as you only asked about one course of block you got different answers!
IN MY OPINION;
I would insulate it on the inside with a metal knee wall cover as suggested or preferably insulate on the outside down below the footer or edge of the concrete slab to lessen cold migration into the wall/slab.

Ceiling mounted Reznor heater... I don't understand the 'metal knee wall cover'? But I do grasp that in spring/summer it'll prolly be a good idea to attach some foam to the cinder block on the exterior.

 

[walrus]

I have one course of block also. I put 2 inches of foam over the outside down past the edge of the slab. I have a radiant floor so it was important to keep that area warm