DYI roof vent repair

You can repair your leaky roof vent boot yourself. It’s easy! 

As a home inspector in the Stillwater, MN area, one of the reasons that I make a point of getting up on a roof is because it’s important to look for leaks and potential leaks, and some problems are hard to see unless you get right up close and look.

Plumbing vents are a great example. It seems that the cracks I’m looking for are often only visible from a very close vantage point. I know that most homeowners (wisely) stay off the roof. If I don’t inspect the plumbing vents, who will?

Don’t let’s get ahead of ourselves, Joe. What’s a plumbing vent?

Oh. Those white (PVC) pipes coming out of the roof at various locations. They let air in and out of the sewer pipes, so that the bathtub or other drains don’t glug and glug when draining. A water “slug” can pull all the water from a sink drain. The water in a sink drain is needed to keep sewer gasses from entering the home. I know this is more than you want to know.

Split plumbing vent boot
A split vent boot can let rain in, causing stains on the ceiling

A split forms when the sun degrades the rubber. You can caulk the split, but such repairs are temporary.

Always PVC?

Nope. Older vents are made of cast iron. They have metal covers on them, and are flashed with a sheet of lead. Lead is soft and doesn’t rust. But there is one problem; squirrels LOVE to eat lead!

Those little holes are from squirrels actually eating the lead!Lead flashing, chewed by squirrels

Anyway, the plumbing pipes are open on top, because it’s okay if rain gets in. The PVC pipes are sometimes cut at an angle, and that’s okay too. They should end one foot above the roof. Not too much more than that, though. If the moisture-laden air gets cold in the wintertime, frost could build up and clog it. Not to worry; my uncle would be happy to come by with a .22 rifle and shoot the frost plug off. (Call first. Mornings are better, because he starts drinking at noon.)

After a few years in the sun, the rubber boot at the base of the vent gets damaged, and can start to crack. Even a tiny crack can let in rain, which can stain the ceiling below.  

Replacing the boot is not too hard. If you can remove and replace a shingle, replacing a plumbing vent is absolutely doable. But if you have more cash than talent, there is an easy solution:

Perma-boot, plumbing vent repair

Perma Boot

Nope, they didn’t pay me to advertise. I just like the product.

There are YouTube videos on how easy it is to repair the damaged vent boot, but the company’s installation instructions are all you need to know.