Patching a pitted garage floor

Q: How can I patch my garage floor? It’s pitted and low in the middle, causing water to pool. I’m thinking of applying a 3”-thick layer of masonry patching compound I’ve seen in stores. What do you think?

A: I'm familiar with masonry patching products you buy in bags and mix on site, but there’s a problem in your case. While these are fine for small jobs, even a tiny garage floor is way too big for this approach. You'd be better off to have some ready-mixed concrete delivered by a truck, after making the necessary preparations for a good job. The trick is to clean the surface well using a pressure washer, then apply a bonding agent to the surface before the pour. This is a white, acrylic liquid that's sold by different companies. You brush it onto the concrete before pouring the new stuff on top. For small patches you can also use bonding agent to replace some of the water you’d normally add while mixing. All brands I’ve used work very well.