Roof vents and chimneys are known in the roofing industry as roof penetrations because they stick up through the roof and shingles have to fit around them. This characteristic makes them highly susceptible to leaks if not handled correctly during reroofing.
Find out some common problems with chimneys and vents that a roofer will look for during an inspection.
Too Much Caulk, Tar, or Mastic
Chimney flashing is a two-part system: there’s an upper piece and a lower piece that overlap. The upper piece needs to be set into the mortar of the chimney, and a line of caulk is used to seal it in. But that’s all the caulk you should need. If your chimney is surrounded by caulk or roofing tar, or if random patches of tar or mastic are found, that’s a sign of problems.
Excess roofing tar is often a sign that the chimney leaked in the past and someone decided to take the quick route rather than doing a complete repair. The unfortunate thing is that these quick repairs tend to be temporary, so your chimney could start leaking again at any time.
The same can be said for excess tar and caulk around vents. And in some extreme cases, instead of the correct flashing or boot, an inspection reveals that only roofing tar was used to seal the junction between the vent pipe and the shingles.
Incorrectly Installed Flashing
Flashing issues are one of the most common reasons for leaks, especially chimney leaks. This is one big reason why you need an experienced professional to do any roofing work for you. A handyman or an amateur may not have any idea how to correctly source, install, overlap, and seal the flashing.
- Some common flashing installation problems with chimneys and vents include:
- Not enough flashing installed
- Wrong type of flashing use
- Flashing installed but shingles not cut correctly to form waterway
- Flashing overlapped incorrectly, so gravity pulls rainwater underneath
- Chimney flashing not set into chimney mortar correctly
As you can see, flashing is quite easy to get wrong in a variety of ways, which is why you need a trusted and time-tested contractor.
Worn-Out or Missing Components
Believe it or not, some roofing companies simply reuse the same flashing when they redo your roof. This is suboptimal from your point of view because even if it’s in good shape now, pre-used flashing is less likely to last the entire life span of your new roof, meaning you’re more likely to need repairs.
If your roof is a few decades old, even flashing that was new at the start may be worn-out now. And even if your chimney is made of masonry, it can also wear out given enough time.
Sometimes, vent components are missing altogether. For example, the storm collar and the vent cap are critical for correct function of furnace vents. Without a storm collar, water can leak through the roof, and without a vent cap, the vent could allow carbon monoxide back down into the building.
No Chimney Cricket
Not every chimney requires a chimney cricket, but it takes a roofer with industry knowledge and experience to know at a glance whether yours requires one or not. A cricket might be required for a few reasons. If your chimney is at the low end of a long slope, for example, or if it’s especially wide, it will need a cricket to help drain all that water away.
If your roof has no cricket, water can simply pool behind the chimney. Dead leaves and other debris can also get caught there, compounding the problem. Eventually it will leak and the area of roof deck behind the chimney will start to rot. Significant damage could occur to your roof by the time water damage starts showing up inside your house.
These are just some common issues with chimneys and vents; others can occur as well. Other roof penetrations, such as satellite dishes or solar panels, can experience similar issues. If you’re experiencing roof problems or if you just had a roofing job done and need a third-party inspection, get in touch with Amenity Roofing, Siding & Gutters LLC to learn more.