Insulating inside the Concrete Block of House Walls

I have a cement block home with a decorative stone exterior and plaster walls interior - no insulation. I had been talking to a few businesses that say they can use blown in insulation by drilling into the blocks from the interior of the home. Does insulating the interior of the blocks sound practical? I am hesitant as the joining blocks/mortar can conduct the most heat/cold and therefore the insulation blown into the center of the blocks would not improve fuel efficiency. Or, could there be space between the plaster walls and the blocks that can have insulation blown in? Any knowledge on this would be appreciated.

p.s. - The comany, Home Engery Resource Solutions (Hershey), says they will take care of patching the holes and give it a lifetime guarantee. He said the insulation they use is Green Barrier or All-side), but I did not find that via google search. Price to do my home is around $2800 (came down from $3500). My neighbor got the same price (his house is smaller than mine) after they started him near $7000. Even if this company is full of it, by using another company, I am wondering if blowing insulation into the insides of the blocks/inbetween blocks/plaster walls is worthwhile? Foam? Fiber? Vermiculite?

Thanks!!

I'm in the same predicament you are and hesitant to pull the trigger because I can't see what they have done. For all I know they could be blowing air in there. If I was going to do it I'd probably be looking at foam applications because that has the best method to get into all the nooks and crannies.

The insulation should help considerably. The heat has to travel a considerable distance through the block, trapped air is great insulator but you don't have trapped air. Adding insulation into the gaps will narrow the area where heat can easily be transferred.

thanks Richard. They do give a lifetime guarantee (is the guarantee guaranteed though? haha )

Nice lyric quote from the best band of any land! Hope your going to see Rush in October!

I am skeptical that filling the voids in the blocks will do much...the milkhouse & offices at our farm were in a large block building, and the block cavities were filled with vermiculite. On real cold days there would be frost on the inside of the outside walls...the webbing in the blocks and motor is a direct path of thermal loss to the outside. We decided to better insulate the office, and put up an inside wall with hard foam insulation. I don't remember exactly how we did it, but I think they put 2x4's against the block wall, put the pink board over that, and then sheetrock. Whatever the combination, you could just about heat the room with a candle afterwards.

Whatever path you chose, don't forget that insulation is practically useless if the wind is blowing through or around it. Stop the air leaks.

Rob R. wrote: I don't remember exactly how we did it, but I think they put 2x4's against the block wall, put the pink board over that, and then sheetrock.

That's not going to happen here. The plaster walls are almost perfect and the time and expense involved would pretty much negate the benefits anyway.

We got an estimate on the blocks outside doing 2*4's, insulation and siding but it was like $22K. That's not going to happen either.

Richard S. wrote:

Rob R. wrote: I don't remember exactly how we did it, but I think they put 2x4's against the block wall, put the pink board over that, and then sheetrock.

That's not going to happen here. The plaster walls are almost perfect and the time and expense involved would pretty much negate the benefits anyway.

We got an estimate on the blocks outside doing 2*4's, insulation and siding but it was like $22K. That's not going to happen either.

I wasn't suggesting that was the only way to go, just relaying my only experience with insulating a block wall. In our case the building was heated with propane, which really changes the ROI on such a project. In the of a home heated with a stoker boiler and "cheap" bulk coal, the break-even on any kind of insulation project will be much longer.

I agree with Rob, as long as you have that path of concrete block it will just follow across. The modern poured concrete into a hollow foam form is the best I have seen but that's for new construction. I have seen the same thing where you can actually see where the mortar joints & the solid part of the blocks are by the depth of the frost. I can see where it would cut down on noise transfer but I would also think your creating a habitat for mold.

If you are just filling the cores, the payback will not be there. The webs of the concrete block create a thermal bridge that conducts the heat. There is some improvement but on an annual basis, you might only save 500 to 700 btus per year per square foot of wall.

If you are heating with coal, you will save about $.01per sqaure foot per year. If it costs $1.00 per square foot to insulate, then you have a 100 year payback.

If you can install continuous insulation on the inside or outside, then it would be a differend story.

I have done a few basements with firring out w/rough cut ( gotta love the Amish on that one) 1X4's & putting sheets of 1" 4X8 foil faced styro. we used 1/4 inch sheet rock---1x4's were 16" on center--taped & painted-- it made a significant difference--these were all DIY jobs with friends & the cost was minimal, the outcome outstanding. Unfortunatly if you have to go with a Contractor--you get a few bids & take the lesser of the few evils---kinda like politics anymore As for the blow in whatever---sorry, if I can't see it, I don't buy it.

Thanks for the responses! Talked to the guy again - Not a foam, but Grenn Barrier is said to expand after being blown in. It will be going between the blocks and plaster wall (in the space the joices create) so it's aimed to be a contant barrier as opposed to what would be inside the blocks. So how does near $3000 for ~1000 sqare feet of wall sound? Seems steep...

I guess I'll repeat--get more then one bid if you think he's high!

Frackstoker wrote:Thanks for the responses! Talked to the guy again - Not a foam, but Grenn Barrier is said to expand after being blown in. It will be going between the blocks and plaster wall (in the space the joices create) so it's aimed to be a contant barrier as opposed to what would be inside the blocks. So how does near $3000 for ~1000 sqare feet of wall sound? Seems steep...

The price does not seem unreasonable. Material probably cost about $1 per board foot and there is considerable labor in what they are attempting.

The question is how much will you save and what is the payback? It probably won't save you more than 7 to 10% of your heating bill unless you have leaky exterior walls that the material will plug. Judgement call on your part.

Sorry, some people want to get ripped off. I would go with inside insulation foam sheets and sheetrock period. Look at a typical 16" block. Say the ends and center are 1", 1-1/2", 1" wide. That's 3.5" over each 16" that's still concrete. Fill your block with whatever, and you still have 21.875% of the total wall that is still concrete, even more with the mortar joints.

Then like Sam said there's the condensation problem that might arise with loose insulation. Don't forget there will be mushed out mortar all along each course of block on the inside, which could prevent full fill of loose insulation.

These people are going to come in and drill holes every 8" all across the top of your interior walls and make that all look invisible when they leave?

I googled those names and came up blank except http://www.alside.com/index.aspx?page=30

If your exterior is decorative stone, I say your only viable alternative is foam panels on the inside.

"Lifetime Warranty" - red flag. What the hell does that mean? Ask for the last three customer's numbers and call them to see if they're satisfied.

You could probably get an infrared thermal survey of your house free from your utility company.

Do a little more research for a few days and look into your best options. Everybody is getting the nesting instinct at this time of year, don't let it affect your best solution.

Just my 2 cents. I had a customer that had his basement finished by his brother-in-law. In a swampy neighborhood. Black mold got in everywhere. The guy was a stockbroker, really nice and decent customers. Then they had a baby and that baby had severe respiratory problems from the get-go. I tried to tell them but they wouldn't listen. They preferred grief, angst, medical bills; to gutting the botched basement reno and doing it over correctly. Heartbreaking.

Also, $3000 will get you 10 tons+ of coal!

Dann757 wrote:These people are going to come in and drill holes every 8" all across the top of your interior walls and make that all look invisible when they leave?

They do it on the outside, mine is just parged. Easily patched, you only have to match the paint and you'll never see it unless you got an idiot doing the patch.

On a stone veneer? I could do that, but kind of time consuming. My free advice is worth what it costs I guess. I gotta do everything myself; because I'm cynical from a lot of experience seeing a lot of retards over the years calling themselves contractors

Case in point; I've had to spend so much time explaining my work to the current customer it's unbelievable. After a lot of discussion, the lady hired a crew to repair her high top colonial front porch. I agreed, more than a one man job. I try to be a good guy, and have been feeding her my best info on what these dunderheads are doing. Their carpentry is acceptable, but they are putting Azec columns in. I told her you have to glue Azec joints with Azec glue. She told the crew she expects that; they mocked her and told her yes, they use glue sticks. Then they said yes, we use Azec glue. Went over the other night and checked their column wraps, which were 3- side prefabbed on the ground. They botched the glue, the seams were loose and gapped. They used non-recommended air gun fasteners and missed the shots all along the columns. I'm not the lady's damn husband, boyfriend, or daddy. I see it all the time.
The lady thought "Angieslist" was some kind of guarantee of reputation. I gotta back off I can't police the world.

If the guy wants to spend 3 large for a minimal return, good luck to him.