On a tile roof in Chilliwack, the leak was coming in around the electrical mast, the pipe that carries the power line up through the roof. When we got up there, the problem was easy to spot. The rubber boot around the mast was torn, and whoever installed it had used the wrong kind of flashing for a tile roof. Here is what was wrong and how we fixed it.
The problem
Two things had gone wrong. First, the rubber boot that seals against the mast had split and torn, which on its own lets water run straight down the pipe and into the house. Second, and this is the bigger issue, the flashing had a flat, solid flange. Tile is not flat. It has a raised, wavy profile, so a flat flange just sits up on the high points of the tile and leaves open gaps underneath along every channel. Water blowing across the roof runs right under it.
Why a flat flange does not work on tile
On a smooth roof like asphalt shingle, a flat flange lies down and seals fine. On tile it cannot. The flange bridges from one high point to the next and never touches the low channels in between, so there is a permanent gap for water to get under. It might look sealed from a distance, but water follows those channels, and on a tile roof the channels are exactly where the water runs. The torn boot just made an already leaky detail worse.
The fix
We replaced the whole thing with a mast flashing made for tile. It has a larger, malleable flange that we shaped down into the profile of the tiles, so it presses into the channels instead of bridging over them. That gives it full contact with the tile and a watertight seal all the way around, and the new boot grips the mast the way it should. Now water running down the tiles hits the flashing and is carried over the top of it, not under it.
Why it matters
Roof penetrations like electrical masts, plumbing stacks, and vents are the most common place a roof leaks, because they interrupt the smooth path water wants to take. On tile especially, the flashing has to match the shape of the tile or it will leak no matter how much sealant is smeared on it. Using the right part for the roof type is the whole job.
If you have a tile roof and you are seeing a leak near an electrical mast, vent, or pipe, it is worth getting the flashing looked at, because sealant alone will not fix the wrong flange. We repair tile roofs across Greater Vancouver and serve Chilliwack and the surrounding area. You can also read why we replace roof vents on tile roofs with lead flashing. Call 778-389-5564 for a free estimate.