Applying the concrete overlay was the last major piece of work to be done on the office project. Unlike stamping and staining, overlay has a different texture and allows precise matching of existing patterns.
The challenge we faced is matching the appearance of the new office patio with the existing pool deck. The pool deck had an existing concrete overlay that was applied by the previous owners a year before we moved in. The overlay made it look as if this old pool was brand new. It's a beautiful appearance and one of the reasons we liked the house.
We originally planned to stamp and stain the new patio but quickly realized we had to do an overlay to match the existing deck. It turned out to be relatively simple and took only two full days, start to finish. The resulting new overlay is virtually indistinguishable from the existing overlay.
Concrete overlay is accomplished by taking a white mortar and applying a layer of it over the top of existing concrete. The layer is applied at a thickness of approximately 1 inch.
The overlay is allowed to dry for awhile but before it is fully dried, the mason goes through with a trowel and carves out all of the "stones". This handcarving allows the mason to match the pattern in the existing overlay.
The overlay is then allowed to dry overnight. In the morning, the mason comes back with buckets of colored stain and goes about painting each "stone" in the overlay with the appropriate color. This again allows the mason to match the colors in the existing overlay. After staining, the mason applies new mortar to all of the joints that were carved out. The effect is a patio which looks like stone and mortar as opposed to concrete.
In our case, everything was a perfect match. This part of the project was one of the few that exceeded our expectations.
The only difference between the old and new overlays is that the new overlay has just been sealed and so it appears a bit shinier than the old. We're going to bring the contractor back in the spring to wash and reseal all of the existing overlay as well.