A roof is one of the most important necessity of life. It helps keep intruders out of our dwelling spaces, and protects us from the harshness of nature. Here in the Dallas area, nature tends to show its harshness most through rain, intense heat, sleet, etc, and if your roof is not properly maintained, it can ultimately lead to a roof leak.
The fact of the matter is that a roof leak can be difficult to diagnose. Different weather conditions tend to cause leaks in different locations on your roof. Here are some common places on a roof that leaks are found:
- Vertical Slits – Vertical slits between shingles are the first places you should look for corrosion that might be causing a leak. Particularly in 3 tab asphalt shingles, it is not uncommon for leaks to develop in the top 3 inches of each vertical slit.
- Missing Granules – These ceramic, color coated pieces of crushed rock protect the asphalt from the destructive ultraviolet (UV) rays of the sun. When they are over exposed to sunlight, the asphalt within the shingle begins to corrode. However, granule erosion in the vertical slit area” tends to happen when water drips from the shingle above. Since this is a small, narrow area, it’s difficult for the sun evaporate any moisture in here. The granules at the top of each slit receive twice as much energy from the dripping water as the granules on either side of the slit. This might not seem like it would do all that much damage, but over long periods of time, roof leaks due to this are not uncommon at all.
Chimneys contain various types of flashing, and if there is a malfunction with this flashing, a leak is likely to occur. Even a hairline crack above the flashing can allow lots of water to run behind the flashing. Look for soldered corners of your flashing that might have been broken, or have holes.
Skylights are a beautiful feature on a home, but their downside is that because they penetrate and interrupt the roof surface, they are a common contributor of a leaking roof. Water flows down a pitched roof (or immediately collects on a flat roof), builds up in the skylight – eventually finds a place around the flashing where it seeps inside, and onto your head.
The most important thing you can do to avoid leaks in your roof valleys is to trim your shingles correctly. When you trim a shingle for a valley you end up with a rough point on the end of the shingle. If a second cut is not done to make this point straight, water can travel along the top of the shingle and find its way into your home.
Specific Types of Flashing
- Wall Step – This flashing rests where a roof extends alongside a vertical wall. As each new row of shingles is laid, a step flashing is installed over the shingle next to the wall. Part of the flashing is laid up on the wall, while the other part gets covered by the next row of shingles. Look for corrosion or rust on this flashing. Ideal you should only be able to see a small portion of this flashing.
- Head Wall – While some roofs extend alongside a wall, others stop where a wall has been constructed. In this case, head wall flashing must be installed to direct water streaming down the wall, away from the stopping point of the shingles. This flashing may be behind wood siding, or in front of a brick wall. The flashing should extend over the shingles by three inches, at least. If the wall consists of masonry or brick, the flashing must bend and extend an inch into a mortar joint.
- Plumbing Vent – Many types of plumbing flashing contains a rubber seal with an aluminum flashing. Unfortunately, the rubber seems to have a lifespan of only about a decade. With that said, it’s important to keep an eye out for cracked rubber around the plumbing pipe. Flashing should dive up and under the shingles that extend up the roof from the center of the plumbing vent. The bottom half of the flashing should be exposed, and actually cover all the shingles.
- B-Vent – B-vent flashing is generally the same thing as plumbing vent flashing, but they tend to have a metal storm collar. The storm collar fits securely around the vertical pipe, but if it’s loosened, a leaking roof can occur.