Roof Leaks

John McKenna

AMERICAN HOME INSPECTION

One of the most common types of roofing seen on a residential home is the three tab composition shingle.  They are intended to provide many years of service, if installed properly on a home.

One of the seven wonders of the world can be a roof leak.  They are one of the most common problems listed in a home inspection report and yet very hard to see with the naked eye.  Once moisture has penetrated the roofing or flashing, you can have big problems real fast, from just a small leak.  Moisture is conducive to fungi-mold, decay and termites.  It's important to understand installation methods and spot red flags as soon as possible.

THINGS TO LOOK FOR AND WHY?

Roof penetration points are the most common areas where a roof leak can start.  Improperly installed flashings at wall intersections, gaps in the flashing around the chimney, old rubber gaskets on the roof jacks cracking, etc... can be some of the most common areas of concern.

Sometimes fasteners (nails, staples) can work their way up and start pushing up and through the shingles, or cause areas of the flashing to become loose.  It's wise, from time to time, to check the condition of things like this to ensure that you can head off a small problem before it gets any worse.

Those nice whirly vents on a roof can allow moisture to penetrate them when you get a hard blowing rain and this is why you see some people wrap plastic around them during the winter. The ridge vents can become loose over time and allow moisture to blow under them during windy storms.

Have you ever noticed a patch of shingles on the roof that curl and become brittle while the rest of the shingles look fine all around them?  This premature aging of selected patches of shingles is why I said that roof leaks are one of the seven wonders of the world.  One reason for the development of this condition is moisture being trapped in those shingles for too long, such as a pile of leaves, or if the shingles were trapped at the bottom of the pile for too long during the construction process.  Shingles have to breath and dry out to stay healthy, and this is why you will see some go bad in the valleys of a roof when leaves are allowed to build up and trap moisture.

When doing a roof-over replacement, some roofers will apply tar patches in some location, instead of dealing with the roof jacks and flashings properly.  This may last for a little while, but tar patches crack and separate in time and then you have a potential roof leak waiting to happen.  Getting a cheap price for a new roof job is not as wise as finding a good roofing contractor who will do the job right.  By the time you discover you have a roof leak, expensive damage can already be done.  Then trying to find and stop a roof leak can be very difficult and sometimes requires several repair visits to finally stop the problem.

Some leaks are present but do not show up every time it rains, but will reveal themselves over time and under certain conditions.  Exterior siding touching the shingles can shorten the life of the siding because trapped moistures absorbs into the siding and keeps the shingles from drying out also.  Shingles that do not extend beyond the edges properly can allow moisture to penetrate under them when there is high winds sometimes.  Dirty gutters can block the drainage flow just enough to cause decay to form on the edges of your eaves as the moisture backs up and looks for a way to disperse. Water traps can be created at various transitions where the shingles intersect with walls or porches and these areas should have proper flashings and not just caulking.

Sun light drys out the shingles and rain causes the granules on shingles to wear off.  As time goes by, the shingles may become compromised in areas and the roof may need a service check for repairs. The question comes at a certain time as to "when do you replace the shingles?".  If you see the majority of the shingles starting to curl, crack, and most of the color is gone... you need to budget for repairs.  Look inside your gutters sometime and you can see all the granules that have washed of your roofing over time.  Waiting too long can lead to costly damage to your home.

Always seek professional advise when seeking to evaluate your roofing concerns.  Be careful not to put a double layer of shingles on a roof that cannot support it properly.  You can expect about 16-18 years out of 20 years shingles and about 26-27 out of 30 year shingles (depending on the manufacturer and environmental conditions).

The steeper the pitch on your roof, the more years you will probably get from your shingles.  Your standard shingles are intended to be installed on a roof with enough pitch to provide adequate drainage and lower pitched roofs may work, but need special installation methods.  If you install shingles on a low pitch roof, they may work for a season, but develop problems under certain conditions and with age.  Be careful if you walk on a roof to inspect it.  Falling off your roof will not impress the  neighbors and can damage the flower bed, as well as vital parts of your body. You'll probably remember this advise on the way down.

John B McKenna is a Certified Master Inspector serving the East Texas area. John has been licensed by the Texas Real Estate Commission (TREC) and approved by TREC as an inspector trainer. He has more than 25 years experience in the construction industry and is certified by the National Association of Certified Home Inspectors (NACHI). He continues to update his yearly education and testing requirements. Visit his company website at www.texas-inspection.com, or call his office at 1-888-818-4838 (Toll Free) for more information. 
 
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