If I had to guess how many new roofs are installed in the U.S. each year, I’d say it’s in the hundreds of thousands. So the odds are pretty good that a new roof is in your future — maybe even within the next few years.

If you’re like most homeowners, you wring your hands over the possibility of a leaky roof. It’s a valid concern, but it’s important to understand that the vast majority of roof leaks are at the flashing, a transitional material that connects your roof to anything that isn’t the roof. Rarely does a leak form in an open field of shingles.

Flashing is found near chimneys, dormers, skylights, plumbing vent pipes and any other vents that extend from the roof to expel air from your home.

Roofers commonly use vent-pipe flashing that has a rubber boot attached to an aluminum flashing base. The issue with this flashing is that after 10 years or so, ultraviolet (UV) rays from the sun cause the rubber to crack and split where it touches the vent pipe. Water can enter here.

I’ve discovered a better vent-pipe flashing made from powder-coated steel, and it has a special siliconized rubber boot. Based on my own testing, it can last 50 years or more. It’s made by Lifetime Tool. I’ve posted a video at AsktheBuilder.com that shows exactly how to install vent-pipe flashing that I urge you to watch.

Do not use caulk on a roof to help seal joints in flashings. Caulk is not a permanent roofing material, and it’s also susceptible to damage from UV rays. Flashings should be made from metal that you can solder. Copper is an excellent flashing material. Talk to your roofer about flashing materials that can be soldered.


As for flashing around a skylight, I’ve had the best luck with a brand called Velux, which sells pre-engineered aluminum flashing kits. The base and head flashings for the bottom and top of the skylight don’t require any soldering. I’ve installed these on countless jobs and have them on my own home, and I’ve never had a leak.

Choosing the right nails to fasten your roof to your home is extremely important. Read the installation instructions for the shingles you decide to use to see which nails they require so you don’t void your warranty. Pay extra attention to the length of the nail and how far it must penetrate the wood roof deck.

My best advice is to select your roofing material before talking with any roofers. Once you’ve chosen the material, read all of the installation instructions provided by the roofing manufacturer. That way, you’ll understand the process well enough to ask the right questions when interviewing roofers for your job.

Tim Carter has worked as a home improvement professional for more than 30 years. To submit a question or to learn more, visit AsktheBuilder.com.