Our sister Margaret was married recently, and the reception took place in Carmel, CA, at the home of her employer. Touring the home of her boss, who is a remodeling contractor, was a treat for us.

That evening we left with a remodeling idea that is unusual, interesting and cost-effective, too.

The idea, which we'll pass along, was the reuse of old concrete from a cracked-up old patio to structure a new one. After standing on the remodeled patio for over an hour, we had no idea that it had been made from concrete. We both thought the tiles were real stone. We eventually learned that we were standing on pieces of broken concrete mortared together to look like stone. The contractor explained that he had decided to break the old concrete into small pieces ö about a foot square dig out the dirt below, add a sturdy sub-base and then mortar together the broken concrete pieces as if they were pieces of natural stone. The finished product was magnificent, beautiful, artistic and, best of all, inexpensive.

Using a sledge hammer to break out the old patio can produce pieces of concrete that are not uniform in size. The rental of a small electric jack hammer can make all the difference. It can be used to create pieces that are relatively uniform.

Once the concrete pieces have been broken up into "concrete tiles" they will have to be set aside so that the work of digging out a layer of earth can be undertaken. The earth removal adds space for a bedding layer, usually sand. The sand bedding layer is used to support the underside of the newly created tiles, and also makes it easier to get an evenly finished top surface. Besides making placement easier, the sand is stable and does not radically expand when wet, or contract when dry, which is what most soil does. Sand is easy to work with and inexpensive, too.

Although a great deal of time can be spent trying to fit each of the randomly shaped pieces together, the patio we saw utilized mortar joints that averaged one inch in width and varied from about half that width to some areas that were about twice as wide.

The sand sub-base should be about four inches in depth. Any kind of sand will do. Using a garden hose, wet the sand thoroughly to gently compact it and then wait several days for the area to dry out. Apply a shovelful of mortar directly onto the sand base and lay the first tile directly into the mortar. Place the thickest piece first. Doing this will ensure that you won't have to dig deeply into your sand base for all pieces to fit flush on top. After several pieces have been laid in place, be sure to scrape away excess mortar. Don't use water to remove the excess. Doing so can result in a mess that could take hours to clean up. The idea is to uniformly place each piece so that the patio is level or graded for drainage.