Requirements for Fixing Clay Roof Tiles

Materials

• Some roofs require temporary protection from moisture while the repair is going on. In these cases, use a sheet of plywood, roofing felt, plastic or roll roofing to protect the roof for a few days. Some workers build a temporary scaffold covered in polyethylene sheeting for extensive repairs. Use a roof-tile adhesive or sealant to repair small chips and cracks in a tile. More severe damage requires new tiles and fasteners, usually nails. Wooden pegs may be used to secure clay tiles in historic restoration work.

Precautions

• Always wear work gloves and safety goggles to protect hands and eyes from flying chips of clay, especially when removing tile that is cracked but not yet broken. Walk carefully on a tile roof, since the surface can be uneven and difficult to stand on. Wear nonslip shoes and evenly distribute weight to reduce the risk of a fall. High-profile tile shapes, such as mission and barrel styles, easily break when walked on. The U.S. Department of the Interior recommends placing planks, sandbags or pieces of plywood on the roof where workers walk, to distribute weight and prevent further breakage.

Repair Technique

• Remove broken tile using a hacksaw blade or slate ripper, which cuts the fasteners holding the tile in place. A pry bar also may work for some tiles. In most cases, tile fasteners are hard to reach without moving the tile itself. Place a piece of scrap wood under the tile that overlaps the problem tile, making it easier to reach the fasteners. If necessary, break the old tile using a hammer, but take care not to damage the surrounding roofing. Nail the new tile through the old tile's nail holes if possible. If other tiles cover the nail holes, use a tile clip or a piece of copper stripping nailed to the sheathing below the tile.

Considerations

• Historic clay tile may be difficult to match, as many colors and types of clay are no longer readily available. When replacing broken historic tile with modern pieces, consider removing an existing tile from a non-visible part of the roof to make the repair. Then use modern tile to fill the gap. This maintains the look and feel of the historic clay roof, and reduces the risk of a patchwork appearance. Avoid using machine-made tiles to replace handmade historic pieces. The difference in appearance stands out, even at a distance.