Installing stone or brick over an existing concrete pad is not very difficult but it will take some time. Adding stone or brick to a concrete patio or porch can add a new level of sophistication and beauty to an outdoor area. In addition, installing stone or brick over a concrete slab can cover unsightly cracks or breaks in the concrete.
Lay out the stones on the concrete pad without using any concrete mortar. This dry run allows you to determine which stones must be cut to fit properly. Arrange the stones in a varied manner, putting stones of different sizes next to one another. Avoid placing stones of the same size next to each other. Leave 1/4-inch to 1/2-inch gaps between the stones to act as joints. When working with bricks, lay them in the desired pattern, leaving 1/4-inch gaps between each one. Typical brick patterns include running bond, herringbone and basket weave.
Cut a stone by marking it with a chalk line. Hold a chisel on the line and tap it gently with a hammer, working along the line. Flip the stone over periodically and work from the other side. Continue in this manner until the stone breaks along the line.
Combine one part Portland cement with 2.5 parts masonry sand in a five-gallon bucket. Slowly add water until it forms a thick mixture that holds its shape slightly when dropped back into the bucket. If you are using the concrete mortar to lay bricks, the mixture should be slightly wetter, sinking back into itself immediately after being dropped in the bucket.
Remove the first stone or brick with a tuck pointer by sliding it under the edge of the stone or brick. Pour a small amount of water onto the concrete pad and spread a 1/2-inch thick layer of the concrete mortar mixture onto the concrete pad with a steel trowel.
Press the stone or brick down gently into the concrete mixture, wiggling it slightly to embed it. Wipe the top of the stone or brick off with a dampened sponge to remove excess concrete. Do this immediately or you will have to chisel the concrete off of your finished area later. Continue working in this manner until all the stones or bricks have been laid in concrete. Allow the concrete mortar to dry overnight.
Mix a second batch of the concrete mortar in the five gallon bucket, adding less water so the mixture will be drier. You should be able to mold the concrete with your gloved hand.
Press the concrete mortar mixture into the joints between the stones or bricks with the tuck pointer, filling the joints completely. Remove excess concrete with the side of the tuck pointer, pulling it to empty joints. Fill all of the joints with concrete before continuing.
Clean the stones or bricks with a wet sponge to remove stray bits of concrete mortar. Make sure you get all of the excess concrete off. Then go over the stones or bricks again with a dry sponge to give the surface a clean and polished look. Allow the mortared joints to dry overnight.
Mix a batch of masonry cleaner in a five gallon bucket according to the manufacturer's directions. Using a paint roller, spread the masonry cleaner on the stones or bricks and allow it to sit for two minutes. Rinse the newly installed covered area with copious amounts of water to remove the masonry cleaner to finish the job. This leaves the stones or bricks nicely polished with no traces of concrete on them.