Install Roof Flashing on Aluminum Roofs: 5 Tips

When you install roof flashing on an aluminum roof, follow these 5 tips to do the job right the first time, to prevent leakage and costly repairs.

1 - Clean Roof Surface

Ensure your roof underlayment is free of leaf mold, dust, grit and twigs. Your aluminum roof and metal flashing must fit as snugly over each other as possible.

2 - Use the Best Flashing Material

Durable 40-pound tin flashing is the best for under an aluminum roof. It resists rust better than any other flashing. Paint it with rust inhibiting paint every few years, and it will last for decades.

3 - Solder the Joints

When putting flashing around a skylight or chimney, create watertight, long-lasting joints in the flashing by soldering the flashing any time you apply pieces over each other. Flatten out the soldered joint to remove bubbles and gaps for a smooth surface. The aluminum roofing will fit better both over and under the flashing.

4 - Use a Metal Brake to Fold the Flashing

Professional roofers use a metal brake to make crisp fold lines in metal sheeting. The metal then holds the angle and lies flat against the underlying surfaces.

5 - Start at the Bottom

Start installing the flashing at the bottom of the roof in a roof valley, so that the flashings overlap in steps, sending water flow down the roof.