Excesssive CMU spalling

Anyone seen this before to this extent and want to propose a cause?

1983 modular.
Surface spalling on East and West sides of foundation.

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High moisture in the block. Looks like poor drainage from here. I’d warn about drainage and advise that they may have trouble getting any coating to stick and refer them to a paint specialist.

Did you see any efflorescence?


The inside looked fine.

I agree that moisture got into the block and froze.

The house may have been vacant last winter and unheated. The gas meter was locked out so there was not source of heat.

My other thought was that the block was painted when it was not completely dry and late froze and popped.

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I’m assuming you meant east and west sides of the home. It looks as though the rear portion of the foundation is not painted/sealed, was there any spalling there - or just on the painted/sealed sides?

If the spalling is only on the painted (east/west) sides, then maybe the wrong material was used to seal the foundation, creating a deficiency in the foundation surface.

What about the grade, Mike? It looks negative to neutral against the house. If you don’t see the efflorescence, it may not be moisture however. I’d refer them to a painting contractor and move on.

Yes. Fixed. Thanks.

Good eye. The South facing side was not painted but the North side is and has no spalling.

The home probably does not have gutters on those sides…resulting in water splashing against the block over a period of time…during the winter this can be very problematic…the problem could also be attributed to a non-breathable sealer…, adverse chemicals being used to clean the block etc…I would simply recommend that a qualified masonry contractor be contacted…

There are no gutters but the house has been there for 26 years. The damage looks recent as all the pieces are laying on the ground.

Thanks for your thoughts.

‘…if efflorescence crystals grow inside-the-surface of the unit,
it can cause spalling’

Not saying this is what occurred w/that house,just that its possible.

Sometimes a homeowner/contractor will PAINT/apply sealer on blocks that have efflorescence without trying to clean-brush chtt off.

Someone may have got carried away with a pressure washer.

We had a record number of freeze / thaw cycles, last winter (and you are close to my area). Sometimes, paint will seal in water. I recommend penetrating silicone sealer rather than paint.

Hope this helps;