Never heard of spray foam injected into block cells though I'm sure many try it. Blocks have too much thermal bridging to get much use out of filling cells with any insulation, same is true for moisture transport. The exterior face of block wall is the best location for spray foam application, followed by other redundant water drainage practices if the block is to be backfilled.

Springtime Builders assumed you filled the cells or cores of the block with spray foam is this what was done? Also do you know if the foam was open cell or closed cell type?

Sounds like there is a dampness issue somewhere, are the blocks part of a foundation that is buried on the outside? Are the blocks painted, or sealed in any manner? A lot of questions before any definitive answers can be given.

Used to be able to purchase blocks with foam inserts pre-installed in each cell, it was discovered that as the prior posted mentioned there is way to much bridging to be effective.

I would be afraid that the expanding foam could crack a block. But if that's what they did maybe the foam is forcing ground water out of the block?

Installing spray foam insulation in the cores of concrete masonry units provides some insulation, but it doesn't waterproof the block--irrespective of whether the insulation is open cell or closed cell. The webs can still transfer moisture in the same way they act as thermal bridges transferring heat.

Waterproofing of a foundation wall is best done on the exterior side. In addition, be sure to install gutters and downspouts or a near-grade system for directing rain water away from the foundation.

Thanks for your responses. This is a home in Florida. The block is the walls of the home ( no basements in Fla) This injection spray foam is done to fill up gaps in the cinder block to increase insulation and seal up the home. What my husband and I have noticed is small areas of dampness on the interior and exterior surfaces of the cinder block and it must be coming from the insulation. Wondering if anyone has any experience in this happening to their homes/ jobs and what to do about it. Our gut feeling is that the foam mixture was not mixed properly not allowing the foam to harden.

I'm in Fl and our block is being filled with cement.

Not every cell...only around windows , doors and some areas in between.

That sounds less wasteful. Do the spots smell fishy, stinky or like chemicals?

Was the rest of your block filled with cement?

The foam is probably not a spray foam but a non-expanding foam injected into each vertical core through a small hole with air pressure.

The wet looking stains are from foam that was too liquid from improper mixing proportions. The installer apparently failed to inspect he foam after each cell was filled so the stains occur randomly.

For maximum strength and workability, reinforced cores of CMU walls should contain steel rebar and grout rather than mortar or concrete, all of which contain cement. Grout is stronger and can be poured in order to completely fill each cavity.

Thanks for your responses...no fishy smell, wet stains still there as of yesterday. My husband has decided to just proceed with the job. Wish us luck that there wont be any issues down the line. thanks

We had our 3000 sf shop building block walls insulated with spray-in-the-core material and I would not recommend it. There were mold problems occurred inside from the foaming operation and the thermal results were almost unnoticeable, probably due to the bridging of the block from outside to inside. In hindsight, rigid insulation outside with metal siding on top would likely have been worth the extra cost.

Roseann S --

Not sure anyone else went to school for this but I do have a B.S. in Building Construction Mgmt. and have worked for #1, #4 globally and #12 US over the years. I was researching the affects of concrete filled cells versus foam filled cells and the reason I found this page at all.

My opinion and some facts. Closed-cell polyurethane has an R-value of 7 for every inch and is a very viable, great solution for insulating CMU block walls in Florida. That said, concrete filled block cells only achieves max R-value of 3.75 across the entire width of the nominal 8"inch block. So as an example of when you fill every fourth cell vertically with concrete or horizontally as a bond beam you are going to have much less R-value in these areas.

As such, I was worried about the thermal expansion and contraction through the adjacent blocks in these areas versus the large R-value, roughly 20+ achieved through the foam spray filled blocks.

The stucco and thermal barriers/ waterproofing I am placing on the outside do not change the total efficiency that much and therefore my question and predicament.

I have thought I need devise a plan for some sort of insulation on the inside of the block wall between the face of the furring strip and drywall. Typical furring strips are not usually more than 2"inches or 1.5 actual. Yes you could always use 2x4's and have a larger cavity of actual 3.5"inches to actually insulate but then you are adding even more cost by basically framing the whole house inside of the block wall now.

I hope your following this train of thought.

Could you have an issue with the spray foam not being mixed properly and being too liquid during the initial application, yes. They are supposed to monitor progress and foam expansion as you go. If that wasn't the case and it was installed incorrectly then I would the excess liquid would soon and eventually evaporate you would just be left with an inferior product/application of spray foam with a lesser R-value than what was specified or proposed.

I would ask the spray foam insulation company, the builder or a third-party inspector to verify the consistency's of the foam in multiple locations. They should be able to break off a few pieces and determine its structural bond, adhesion to itself, etc. Review where they started first and maybe the mixture was not up to snuff at the start and whether the problem is only occurring there versus across the whole job.

Sometimes they just have to tweak the two part liquid ration to get the foam to come out right. It is just like a two part epoxy if you have ever mixed those two liquids together before they harden.

Or Is it only where I have noted the different R-values of the two adjacent blocks one being filled with foam and the other with concrete.

Concrete is very porous and thermal conductive substance and the reason there are other barriers in place to insure the homes vapor/water and insulation barriers are intact. Example being the vapor barrier they place under most foundations/ footers or slab of grades (SOG) when they pour them so you don't have ground water coming up through your slab or prematurely deteriorating the rebar of the structural footers. Another example is the epoxy coated rebar they use in large cast-in-place (CIP) concrete super structures for bridges as they are so close to such a vast amount of ocean salt water intrusion even further accelerating the deterioration of internal workings of the structure.

I hope this helps on your journey of discovery and good luck!

To those of you who think there builders and aren't please refrain from commenting i.e., Springtime Builders, Brian who commented that he has " Never heard of spray foam injected into block cells though I'm sure many try it. Blocks have too much thermal bridging to get much use out of filling cells with any insulation" which just makes me cringe that this guy actually calls himself a builder.

Don't be discouraged by your decision Roseann to foam fill your block walls as it is one of the best solutions you could have done to seal air gaps or the insulating properties it provides. I just hope they got the mixtures right.

I have not found my answer yet but scientifically I would think there is excess thermal expansion and contraction that occurs from one cell at less-than an R-value of <3.75 versus the adjacent cell or greater than >R20 and the solution is to add another layer either internal or externally to bridge that gap.

This is one of the books you need to pass the General Contractors test. Not every person can call themselves a GC as their are three building license in Florida.

1.) Residential Contractor (RC) 2-Story and Below

2.) Building Contractor (CBC) 3-Story and Below

3.) General Contrcator (CGC) 3-Story and Above.

University of Florida. Energy Efficient Building Construction

Be Well !

Forgive me for not meeting your commenting credentials TB. I would change one thing in my seven year old post and that would be suggesting insulation be to the interior of the block. Exterior would perform better thermally but tunneling insects are the big concern in hot climates like FL.

I standby my comment to not fill CMU cores with insulation. It's a waste of resources. Foam salespeople might disagree but you would have a hard time measuring energy and moisture benefits from filling CMU voids with anything.

If you want to properly insulate CMU in warm climates follow BSC's advice.

" Not sure anyone else went to school for this but I do have a B.S. in Building Construction Mgmt. and have worked for #1, #4 globally and #12 US over the years. "

A B.S. in Building Const. does not help when the OP posted the issue 7 YEARS AGO.

Ah, so, you're going to infer the cause by the process of elimination?