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Concrete Expansion Joints

Topic: 
Garages and Driveways
Question: 

My home under construction includes a roughly 20' x 27' garage with 2nd story apartment. Appropriate footings and slab thickness. Today I noticed that contractor had cut two "stress release cuts" appr 1.25 deep x1/8" wide that run the length and the width of the garage criss-crossing in the middle. These were intended to "control or prevent unsightely settling cracks". Two problems... 1) the cuts themselves are unsghitely.

They used a hand-heald concrete saw that "ran" some, so the lines do not have uniform thickness and are frankly not that straight either. And due to the fact that the walls were already framed, the cuts do not go all the way to the wall due to the saws clearance. This gives the appearance that the whole action was an after-thought. Just believe me when I say that,in my new home, this is not going to be acceptable. 2)I have seen these types of cuts and expansion joints before but I have never ever seen them in a garage. My question, I would like to fill these holes as if they never existed. I was thinking about cleaning out these cuts, applying a bonding agent, grouting with a concrete slurry and painting the floor if it remained unacceptable. Is there a question here? How should I go about repairing these cuts to look like they were never there?

Answer: 

Hello Kevin,

Expansion joints are a normal and beneficial part of any concrete slab that is larger than 8' x 10'. As such, they should be installed in garage slabs. The normal practice is to install such slabs in the process of pouring the slab.

For example, an impregnated fiber strip can be placed in the middle of a double garage (down the center line) and the concrete is then finished along that strip. Such a strip would be installed in a straight line from one end of the slab to the other.

It is possible to cut such a line after the installation of the slab. And it is even possible to cut a straight line with a hand held saw - but it takes some skill to do that. Your description suggests a sub-standard practice of work.

You maybe able to fill such holes with a concrete bonding agent and some concrete patching material. I doubt if you can hide all of this unless you paint the floor. But my real concern has to do with what this mistake suggests about the rest of the construction work. Based upon my experience, mistakes of this type are often a sign of a pattern of work. I suggest that you re-read you contract, look at the plans and hire a private inspector to help you oversea the project. Don't wait until you have notices other defects, try to prevent any further problems before they get to the point when corrective work is difficult (as in this case).

George