How to Install Roofing on a Parapet Wall

In this video, I wanna show you how to install a torch down roof on the parapet wall itself. Let’s get into it.

Important Measurements to Keep In Mind

All right, now that we’ve got our torch down on our roof installed, I wanna show you how to install a torch down on our parapet walls. It’s similar, presents a few different challenges that the roof deck does not. When you’re working on a parapet wall, obviously you’re worried about sliding down. So when you’re working on a parapet wall, you wanna come down past your cant strip 6 inches, so that’s an important measurement to remember. Your roof membrane should come up past your cant strip about an inch or two, and then the parapet wall membrane will come down 6 inches past your cant strip and you’ll have a double layer of protection in this corner here.

When installing and measuring out the membrane for the parapet wall, we generally work in 3-4 foot sections. If you would do a long run, let’s say a 10 foot run, it gets extremely difficult to balance this out. To work behind it, you’ll probably need 5-6 guys holding the membrane, so it’s always easiest to work in 4-foot sections and just do smaller piece at a time. So we’ve marked out 6 inches past our cant strip, hold it in place with our feet. Once we have this set, we’re ready to cut the top edge. After we cut it to size, we’re gonna flop it back, torch the top half, then do the same thing on the bottom half.

(Watch the video above at 1:32 to see how the roofer installs the top half of the torch down on the wall using a flame.)

Dog Ear the Corner Before Installing the Bottom Half

So we’ve got our top half torched down already. Now we’re ready to torch this down. Before we do that, similar to when we do our laps on our field, we wanna cut this down at a 45 degree angle. Generally whenever you’re overlapping one layer of torch over another on your end laps, you wanna make sure you don’t have three layers overlapping each other in a corner. So doing this will ensure that we have a good seam right here, when we overlap 6 inches on our next piece. Now we’re ready to lift this up, torch it down, and we’ll continue with our next section going forward.

(Watch the video above at 2:58 to see the installation of the bottom half piece of the torch down.)

How to Overlap the Second Piece of Torch Down on the Wall

All right, so we’ve already got one roll, one layer of our torch down roofing on our parapet wall. Generally speaking, we would use a full width of a roll, meaning that we would have this film on our side laps. Now in this example we have not done that. So what we’re gonna do is actually do the same thing that we did on our field, burn this off, embed the granules, so that we have a nice tight seal at our end lap. It’s not all the time that you have this finish wherever you want, so whenever you don’t, the concept remains the same: you burn this off, take the granules off, so you have a nice tight end lap going. We wanna have a 6-inch overlap at our end lap, so anytime that we don’t have the adhesive strip, we’re gonna go 6 inches.

We’re all wrapped up here with this parapet wall, you saw an example of how we did the end lap, how we did the side laps. Really this joint here is not as critical as the rest of the joints on the roof, because again remember, if it does happen to leak here or water does happen to enter here, we still have a layer of roofing that’s going underneath it and up the parapet wall. This really provides us double layer protection in some of the most vulnerable areas which are the corners of the roof. Then the end laps, we also saw how we remove the granules to get a proper bleed out and a good seam, when we don’t have that three inch seam.