What Kind of Caulking Is Used on Concrete Roof Tile Joints?

Expansion Joints

• Concrete roof tiles do not have true expansion joints, since they are not slabs of concrete, but they may still expand and contract in different types of weather. As a result, the caulks you should use, especially where concrete meets concrete, should have elastomeric properties that allow the tiles this movement. Gaps and cracks can result if a less flexible type of caulking is used instead.

Silicones and Other Options

• Concrete roof tiles are joined through nails, clips, mortar beds and other methods. When properly installed, they do not need a layer of caulk around every tile to protect it. But caulks are still important around key roofing areas, such as flashings and valleys, and butyls or silicones should be used in those places to help protect your roof. These caulks are messy, but they are waterproof and effective.

Mortars and Cements

• In places where rooftops meet at right angles or are connected to other types of cement, a roofing mortar or roofing cement may be used. These help embed flashing and counterflashing for proper roof protection while still providing room for tile. Always use mortars and cements specifically designed for roofing applications to increase durability.

Sealants

• Sealant is a general term in roofing that can refer to all caulks. However, it can also refer to the specific coating that goes over the concrete tile as a whole, to offer additional moisture protection. If your tiles do not come with a sealant coating, adding these clear coats may offer more protection. Use a coating designed for roofing and concrete tile materials.