my Old Workshop

How to repair concrete (Part I)

Concrete’s a hard material, but water and temperature changes can damage it, particularly if it’s cracked. Water seeps into the cracks, where freezing and thawing causes it to expand and contract. The secret to long-lasting concrete is to repair cracks and damaged concrete as soon as possible.

Here are some of the materials you can use.

Patching compound. Made of latex, vinyl or epoxy, this material is fine for tiny cracks or patches. You mix a powder with a liquid binder, and apply to the damaged area.

Hydraulic cement. This is handy stuff if you’re patching a leak in a basement wall when the water’s running through, or if you have to work in the rain. Because it sets so quickly — a few minutes — you can patch even when it’s wet. But you also have to work quickly. Just mix up a small amount and use it up fast.

Premixed concrete. Just add water and you’re ready to patch larger sections. Patching mix usually has a little more portland cement in the mix to help stiffen it so you can shape it better. You should have a doughlike consistency.

Start by examining the problem. Is the damage minimal? If so, you can simply use the patching compound. If it’s a larger section, you need to determine whether a patch is in order or you need a full-blown replacement. One of your considerations is how it looks. Like it or not, your new concrete is going to show up. It will be fresh and lighter colored. So if that bothers you, you may want to replace rather than patch.

Next time, we’ll show you how to patch it.