When pressure-treated lumber first appeared on construction sites about 25 years ago, it was hailed as an inexpensive alternative to masonry. Before long, steps and terraces, porches and walkways were being built out of treated wood. But the residential market is ripe for a resurgence of outdoor brickwork for at least three reasons. First, the performance of some treated wood has not lived up to homeowners' expectations. Second, treated wood structures are no longer the bargain they once were. Third, the renewed popularity of traditional architecture is nudging homeowners toward outside brickwork. Residential masonry contractors looking to expand their services can profit from the renewed interest in brick paving. There are two basic approaches to designing brick flatwork. The more traditional is to use a rigid system, with brick pavers laid in mortar on a concrete slab. Today, it's more common to use a flexible top layer of paving brick, set in sand over a compacted aggregate base. In flexible systems, the joints are not mortared. Correctly installed, either type will almost certainly outlive the installer.