Although built-up roofs are durable, leaks can develop. These are most often found where flashing is located, such as at connections between the roof and the chimney, the eaves, or another roof plane. They may also develop where wind has blown the gravel away and exposed the surface to sun, heat, and cold.

An older roof may also develop leaks where the asphalt has blistered or where the layers of roofing felt and bitumen have separated.

To keep built-up roofs in good shape, be sure that there are no bare patches in the gravel. Keeping the roof surface covered with gravel will also keep your house cooler in the summer and warmer in the winter.

If simple repairs do not remedy leaks, the roof surface may need to be replaced. This is a job for professionals; rolling out layers of roofing felt and hot mopping asphalt is more than most homeowners will want to take on.

Modified bitumen or “torch-down” roofing is a popular alternative to classic tar-and- gravel built-up roofs. Easier and faster to install, it consists of a single rubber membrane that is heated with a torch and then bonded to a fiberglass mat that is attached to the roof sheathing.