Recently, after attempting to repair the Great Wall of China with cement, Chinese officials received lots of criticism. Reportedly, the work was not attractive, and it didn't do this great wall justice. If you need to do a concrete repair on a stone wall, you may be worried about making the same mistakes.
Luckily, however, repairing a small wall at home may be easier than you think. Here are some tips to help:
1. Prepare the area first.
Since the cement mixture adheres to the stone wall, prepare the area carefully before you begin to work. Remove loose chunks of concrete by hand and brush out any small particles. If there are loose stones, set them aside, and then clean the wall with a pressure washer on a low setting.
2. Mix your concrete repair.
When repairing a stone wall, don't use plain concrete. If you do, you risk making the same mistake that wasn't appreciated on the Great Wall. Instead, mix one part cement to two parts sand, and add water. Stir this mixture around, and use it immediately.
3. Apply the cement mixture with a trowel.
Use a trowel to apply the cement and sand mixture to the broken parts of the wall. If any stones have fallen out of the wall, hold them in place with your hand, and trowel in the cement around them. If you are not comfortable working with a trowel, use your hands.
As this mixture is not pure cement, you don't have to worry about cement burn as much as usual. However, to be on the safe and comfortable side when you are working with the cement and sand, you should still wear gloves.
4. Remove excess cement.
Once you have finished repairing the concrete holding the stone wall together, moisten a sponge. Rub the sponge over any stones that have cement on them. It is easiest to remove excess cement immediately.
5. Make the cement match.
When you finish applying the cement repair to the stone wall, you are likely to notice that the new cement doesn't match the old cement. There are two ways to deal with this issue. You can pick up some dirt from near the wall and rub it against the new cement -- do this while the cement is still wet so that the soil stains it. Alternatively, you can water down some of your cement and sand mixture, and then gently paint it over the old cement so everything looks new.