Robert Lamoureux: Garage floor spalling repair options

Courtesy photo Home improvement writer Robert Lamoureaux says spalling repair requires either cleaning the area and doing a surface patch or removing the floor and starting over.

Question No. 1

Dear Robert,

I read your article in the Sunday Signal and have a question regarding what has been happening to our garage floor. I have attached a couple of pictures. The house is a little more than 20 years old. We are the original owners.

We’ve had efflorescence occurring in this particular spot for years, and now the concrete is breaking up in this area.

It is in an area right in between where my husband and I park our cars. This has been happening for years, and we would like to get it fixed.

The obvious concern is that there is more going on than just normal efflorescence from humidity.

Based on the pictures attached, do you think we should be investigating the cause for the concrete breaking apart or is this something we can just patch?

If it’s something we should be investigating further, can you recommend someone for us to work with?


— Rita A.

Answer No. 1


Thank you for being a loyal reader of The Signal.

This condition is called spalling. The spalling is due to ongoing water to this area. It appears that the plastic that was laid down before the concrete pour is probably damaged and is allowing the water to leach in this area, causing this condition.

I would clean the area and do a surface patch.

If you saw cut this, it’s only going to recur as the demo will only damage more of the plastic underneath.

The only other option is to demo the entire floor and start over.

I hope this helps with your questions.

Best of luck.

— Robert

Question No. 2

Hi Robert,

I always enjoy your column and have written in a few times. Thanks so much for your excellent advice to me as well as everyone.

I have been converting some of my toggle and dimmer light switches over to WiFi remotes. I completed installing eight switches in existing electric boxes (two sets of two and one four switches). The only difficult thing was getting all the wires and the new bigger switches back into the box.

Anyway, my last set of three switches are the problem. I finally was able to get them wired correctly with help from the manufacturer support, which was fantastic. However, the existing large wire bundles, as well as the bigger switches, don’t allow room to put them back into the electric box.

I called an electrician, who came out and said the way to do it would be to install a new box on the wall below the existing one and cover over the old one with a blank wall plate. I was hoping that a deeper box might exist that could have replaced the old one but maybe that isn’t an option.

What do you think? Thanks so much.

— Bob B.

Answer No. 2


Deeper won’t work as the walls are typically only 3.5” deep. You’ll need to do what the electrician advised or go to a wider box.
If the box is a standard light box, then you’ll have to go to a 4S box, which is wider.

They obviously used the one in question as a chase, and there are too many wires within the box, as I’m understanding your question and dilemma.

In order to do that, you can get a retro fit box (tiger box is what it’s referred to) and minimize drywall repairs.

Best of luck,
— Robert

Robert Lamoureux has 38 years of experience as a general contractor, with separate licenses in electrical and plumbing contracting. He owns IMS Construction Inc. in Valencia. His opinions are his own, not necessarily those of The Signal. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor after that contractor has made a thorough visual inspection. Email questions to Robert at [email protected].

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