I have an older driveway that was installed 42 years ago. It’s still in pretty good shape other than some cracks. These have been patched and are unsightly. I was wondering if I could get an even appearance to the entire surface by applying a thin layer of colored thinset grout over the driveway. Do you think this would hold up to vehicular traffic? If so, how would you apply it to get a nice appearance? If not, what other ideas do you have? — Julie C., San Jose
I’ve got great news for you. Soon your driveway is going to look simply stunning. You can transform its look using colored thinset if you choose, but I’d recommend a slightly different material that will give you the durability you’re looking for.
Perhaps the best news of all is that this is a DIY project if you can muster the help of three friends for just about half a day. Are you sitting down? The total cost of the project should be less than $500, and that includes the pizza and beverages you’ll serve your work crew!
Your photo showing the existing cracks and discoloration was very helpful. For your new driveway to look superb for many years, you’re going to have to do some extra work repairing the cracks. I recommend that you grind them out and use a pressure washer to remove as much debris as possible. Try to open up the cracks to the full depth of the slab.
Once you have achieved this, you need to use any of a number of concrete epoxy crack-repair products to bond the broken slabs together. If you skip this step, the cracks will telegraph their presence through the new overlay you’re going to apply.
It may take you one or two days to repair the cracks using epoxy, but it’s worth it. The directions for the epoxy you choose will tell you how wide, how clean and how deep the epoxy must penetrate to get a lasting repair.
When you’re ready to resurface the driveway, I would highly recommend that you apply a layer of cement stucco to the driveway. You can get by with a layer as thin as 1 / 4 inch in your case. This stucco is very similar to the thinset grout you were thinking of using, but it differs in that the sand particles are much larger.
Thinset usually contains a fine silica sand. To withstand vehicular traffic, you need the larger particles found in coarse or medium sand. Traditional sand usually contains small rock particles that are different colors, and this will actually work to your benefit, since you want a colored surface.
You’ll use just sand and pure Portland cement to make the stucco. I’d recommend you blend one part Portland cement to three parts sand. To achieve the color you want, just add dry-shake pigments that are made for mortar or stamped concrete applications. You can purchase all these ingredients at a store that sells materials to bricklayers and stone masons.
I highly recommend that you make up a test batch of this stucco and pour it onto a plastic sheet in your garage. You want to see what color it is after it cures in 30 to 45 days. The last thing you want is to do all this work and not be happy with the color.
To get the new stucco to bond permanently to the existing concrete, you need to do what some master masons taught me decades ago. They would apply a thin coat of cement paint to the existing driveway just before pouring the stucco. You make cement paint by mixing pure Portland cement with water until it’s the consistency of regular paint.
Just before applying the cement paint, you need to spritz the existing driveway with water. Don’t get the driveway too wet, just damp. Roll the cement paint on the existing driveway just before you pour on the stucco mix. Don’t allow the cement paint to dry. It’s best to work on overcast, cooler days. Sunny, windy days are the absolute worst conditions to do this job.
Use a magnesium float to finish the stucco. You can also apply a broom finish if you want a linear pattern. To achieve a great broom finish, you’ll have to practice to discover the magic time when the stucco is ready to be stroked. Do it too early and you end up with a mess. Wait too long and the stucco gets too hard. If this happens, the broom bristles won’t make a great impression.
I suggest you partake in some on-the-job training to hone your skills. In your photo, I see a small sidewalk between your driveway and front door. Apply this same stucco first to this sidewalk, one small section at a time, until you have a great feel for how long it takes for the stucco to harden enough to apply a finish.
The key to getting even color in the batches you mix is very controlled measuring of all ingredients. It’s also very important that you add the same amount of water to each batch. Too much or too little water will affect the finished color of the batches.
Tim Carter is a columnist for Tribune Media Services. He can be contacted through his Web site at www.askthebuilder.com.