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repairing cellar walls? Answered

 We bought a house last year that had some water damage on the cellar walls. Last summer I redid the drainage around the house as I suspected that that was the reason for the damage. I am now setting out to repair the inside damage. I should not that I noticed no damage to the outside walls while redoing the drainage. 

The inside wall damage consists of 'blistering' and loose light cement/plaster. The cinder blocks seem to be fine and I have not found mold. I have scraped away the loose stuff and will now patch the holes.  I have been told to use a polymer-based household cement but would like to ask the instructable community for advice. 

I basically have to resurface parts fo the walls and patch a few deep holes.  How should I do this?

Thank you.



4 years ago

You won't see damage to the outside walls and don't have to in order for there to be damage to the inside. Humidity alone is enough to do the damage you describe. When I was in college, the admin let us panel the basement rec room. The next day the panel was warped because we didn't put a vapor barrier down first. The panel was removed, and plastic sheeting used as a vapor barrier and the panel went back up and stayed. You need to seal the outside wall from the outside. The humidity from damp earth is enough to ruin inside plaster.


9 years ago

i would apply a mortar like coating called "Surface Bonding Cement" it is a fiber reinforced waterproof structural coating that you trowel on about 1/4" thick on a clean (free of paint and loose chips) stone or cement block wall and when dry is strong and waterproof 
it comes in white or grey and you can paint it when dry if desired
it was made by amstone at one time but you should be able to find it at concrete supply places that sell cement blocks
it normally costs about $12-14 per bag


9 years ago

Also, you could use and acro to help to hold it up - they are really strong and can be rented from any large DIY centre


9 years ago

 Thanks Caitlinsdad. This is what I had thought to do. It's good to have confirmation.



9 years ago

Thorocrete is one brand of cement repair but you will find similar products at the home center.  Their site has some answers for you. Essentially you will need a few tools, chisel, wire brush, hammer, etc to clean out and undercut any holes to patch.  Use hydraulic cement to patch - the stuff expands a bit to hold in place as it cures.  There are stucco like thin cements to use to resurface walls. You can then use some masonary or latex based waterproofer coating to seal the wall.  Good luck.