Chimney Flashing Repair: How to Repair Loose Flashing

Many roofing leaks can be traced to worn or defective chimney flashing, and can be deterred by an effective chimney flashing repair. With reliable instructions and the right tools, you should be able to manage this type of repair with very little trouble.

Step 1 – Examine Your Chimney Flashing

Leaks in chimney flashings generally are caused by improper flashing installation or repairs, or by using sealing materials such mortar, tar or grout that has deteriorated or has separated from the flashing. To repair leaks, carefully examine the materials that have been applied to your chimney flashing. Look for holes, shrinking, or separations between sealing materials and flashings, where it is attached to the roof or to the chimney.

Step 2 – Remove Old Sealing Materials

Use a grinder to grind away old sealing materials. Grind into these materials about an inch deep.

Step 3 – Install New Chimney Flashing

On the chimney, install a new metal flashing, the top edge embedded in the brick mortar and sealed with grout. Bend the bottom edge so it curves out onto the roof shingles.

Step 4 – Install New Step Flashing

Under each row of shingles adjacent to the leaking side of the chimney, install step flashing. Make sure the top edge is fastened under the shingles and the bottom edge placed over the top of the chimney flashing.