How to Repair a Tar and Gravel Roof

Common to structures with flat roofs is the use of tar and gravel on its roofing method. Also called built-up roofs, this roofing method use layers of asphalt and membrane material or roofing paper typically topped with gravel.

The tar and gravel roofing are basically designed to last for ten years and some last longer up to twenty years. However, it can easily be penetrated and very susceptible to leaks. Temperature fluctuations often results in leaks in tar roofing, which cause the roofing membranes to contract and develop cracks. The section of the tar roofing where gravel has worn off is also prone to leaks due to weather exposure.

However, minor leaks can be repaired by the homeowner and do not require a complete roof replacement. The repair supplies the homeowner may need can also be found and purchased at a local home-improvement store or a DIY store.

Here is a simply guide on how to repair your gravel roofing leaks:

1. Scrape off any gravel from the torn, cracked, or gouged region of the tar roof using a pry bar to fully expose the entire damaged area but be careful not to penetrate into the roof’s membrane. Widen the exposed area for about three inches beyond the damaged area to allow better patching.

2. Sweep the exposed tear, crack, or gouge with a broom to remove leaves, dirt and other debris. Remember that plastic roof cement works best to clean surfaces.

3. You have to block off both ends of a tear or a crack with horizontal cuts to prevent it from spreading. You can use a utility knife and carve two three inch long cuts into the roof membrane, one at each end of the crack or tear.

4. Then you can lay a 6-inch-wide reinforcement fabric directly over the tear, crack, or gouge. The fabric must overlap either side of the damaged area by 3 inches. Using scissors cut the pre-measured fabric and set the fabric aside.

5. Use a protective gear, such as full-length clothing, protective eye wear, and rubber gloves to avoid direct contact with the roof cement on your skin and eyes.

6. Spread and coat the plastic roof cement over the tear, crack, or gouge using a small trowel. Apply the roof cement into a 1/8-to-1/4-inch thick layer and extend it 3 inches beyond the tear, crack, or gouge. Cover the damaged area well with roof cement to ensure proper grip and adhesion.

7. Then cover the fresh cement bed with the pre-cut reinforcement fabric. Lightly press the fabric into the cement by using the trowel. Then gently rub the trowel across the entire fabric to make sure the fabric reinforcement stays in place.

8. Afterwards apply another 1/8-to-1/4-inch thick coat of roof cement over the embedded reinforcement fabric using the trowel. Next extend the cement layer 3 inches beyond the patched area.

9. Then apply loose gravel over the wet cement bed to blend the patched area with the rest of the roof. However, if the surrounding roof is not coated with gravel, you can skip this step.

10. Curing is about three days.  You have now a better performing tar and gravel roofing.