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Writer's pictureBurke Home Inspections, L.L.C.

Any Roof Can Leak

Updated: Dec 16, 2023

Is your roof waterproof? Believe it or not the answer to that question is, no. Roofs are designed to be water-resistant. Roofs are not designed to be waterproof. Eventually, the roof system will leak. No one can predict when, where, or how a roof will leak regardless of what type of roof material your home has installed. Let's take a look at a few types of roofing materials or roof coverings common in California.


Asphalt Shingles


One of the most common types of sloped-roof covering is asphalt shingles. Asphalt shingles have a service life from 20 to 40 years, depending on the shingle quality, installation, and maintenance. Roof curling, not an Olympic event. When asphalt shingles begin to lose their granular covering and start to deteriorate, crack, or curl, the shingles should be replaced. In the inspection image below, the edges of the older shingles are starting to curl slightly. 












No more than two layers of asphalt shingles should be installed on a deck of a house roof structure at any one time. This is G-rated flashing, anyone can watch. If the second layer of asphalt shingles has been applied, the inspector could check to see if all the flashing materials of the first layer were reinstalled with the new second layer. Roof flashing is crucial to divert water away from the structure's walls, chimneys, and valleys. In the inspection image below, the inspector is checking the roof-to-wall flashing and observing properly installed step flashing. 














Metal Roofing


Another roofing material, more common in colder areas of California, is Metal Roofing. Metal roofs can last 50 years or more if properly coated, painted, or otherwise maintained. Metal roofs may be made of galvanized iron or steel, aluminum, copper, or lead. Each material has its own unique wearing characteristics.












Metal roofs should be monitored for the development of rusting or pitting, corrosion due to galvanic reaction, and loose, open, or leaking seams or joints. The home inspector can check these areas by walking or 'droning' your roof.
















Galvanic reaction (aka bimetallic corrosion) is when two (or more) dissimilar metals are brought into electrical contact through an electrolyte (such as water), one metal becoming an anode corroding faster and the other the cathode corroding slower, than if without the other metal.




Slate, Clay Tile, and Asbestos Cement


These types of roof coverings are extremely durable and may last the life of the structure, if of high quality and properly maintained. All of these roof coverings are brittle materials, are easily broken, and should not be walked on other than by a roofing professional. Recommend requesting before and after photos if your slate, clay tile or cement roof will be walked on. Broken tiles can allow water and moisture intrusion (water entering the building envelope). Any broken tiles should be repaired or replaced by a qualified roofing professional. Moss will sometimes grow on asbestos cement shingles, but it can be removed with an approved cleaner and by a roofing professional to prevent capillary water leaks and pieces of the debris from being washed into the gutters during the wet weather. Below are photos of cracked clay tiles and mossy cement tiles.
























Gutters and Downspouts


When debris collects in gutters it traps rainwater. When water becomes trapped in the gutter the gutters become too heavy for the supports, can pull away from the fascia and fail and or back up into the roofing materials causing water damage, both of which are costly repairs.


Did you know...

How to Calculate rainwater runoff from roof: If your home is 1,500 square feet and one inch of rain falls on your roof, you could collect ( 0.6 gallons x 1,500 square feet = 900 gallons of rainwater). Considering an entire rainy season and or snowfall/melt, that's a lot of water to collect. For this reason alone the following section is a pertinent component when maintaining your roof system.


GUTTERS: All gutters need to be kept clean. They should slope uniformly, without sags, to downspouts. Gutter and downspout materials are usually galvanized steel, aluminum, copper, or plastic. Buildings with sloped roofs can have a variety of drainage systems. With a sufficient overhang, water can drain directly to the ground without being collected at the roof edge. Drainage without gutters and downspouts can damage the exterior wall with overflow. If the roof has no gutters and downspouts or interior downspouts, the inspector should carefully check the exterior walls for signs of water damage. Below is an inspection photo of a gutter holding water and debris. This gutter is clogged.













Hangers or gutter supports should be placed no more than 3 feet apart. In climates where ice and snow are long-lasting (Northern California), hangers should be placed no more than 18 inches apart. The strength of a gutter’s fastening to the roof fascia or building exterior should be strong and secure. Rusted fasteners and missing hangers should be replaced. As well, downspouts must be well-secured also. Downspouts pulling away from gutters and or from their mounts put strain on the gutter system and leave penetrations open to moisture and potentially rot. The inspection image below is of a downspout fastener coming loose from the siding.













DOWNSPOUTS: The general rule of thumb for downspouts is that there should be at least one downspout for every 40 feet of gutter. For roofs with gutters, make sure that downspouts discharge so that water is diverted and travels away from the foundation. Downspouts should not expel water at your foundation! In the inspection image below a downspout is missing the elbow, terminating at the siding, and expelling water against the siding and foundation.















Water is destructive to foundations if it is not diverted away. If areas near the foundation are low or water is pooling near the foundation, have that area brought up to level and with a slight slope away from the home's structure (1"slope/1'run). The rule of thumb for downspouts is they should end in an elbow and drain 5 to 6 feet away from foundation. Having downspout extensions installed or installing them yourself is a great way to move that water away from the foundation. Extensions should be at approx. a 30 degree angle in relation to the ground. The inspection image below is of a downspout diverter; however, it is 2' in length and not moving water far enough from the envelope of the home or the concrete it is draining on to.













As a steward of your home, one of the largest investments you may make in your lifetime, preventative maintenance is of high importance to keeping your investment sound. For more tips on home maintenance, roof system inspections, or any other home related questions, contact us at Burke Home Inspections. We're your neighbor and want to help you enjoy your home!


Permission granted by InterNACHI


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4 commentaires


djwhaley
14 déc. 2023

That’s a lot of great information. My roof is about 10 years old . I should probably have it checked out, and also look at my downspouts, rainy season is upon us!

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Burke Home Inspections, L.L.C.
Burke Home Inspections, L.L.C.
14 déc. 2023
En réponse à

Hi DJ,

Absolutely! It’s a good rule of thumb to have your roof and roof systems inspected annually. Whether you or a licensed and bonded contractor is inspecting your roof, be sure to check all venting for tight seals at the roof. It sounds like you’re on it!


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katiegdisanto
13 déc. 2023

Really helpful and informative! I have a cement roof tile and never thought about having someone do before and after photos when they work on it. Now I will 😀

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Burke Home Inspections, L.L.C.
Burke Home Inspections, L.L.C.
13 déc. 2023
En réponse à

Hi Katie,

Great to hear this information is now a part of your toolbox of knowledge. Most homeowners have no idea what their roof system looks like from, well, the roof system perspective. Getting on a ladder or roof is dangerous, so it's understandable that most people don't do that and therefore rely on the knowledge and credibility of others to properly assess, report on, and or repair any issues. Sounds like you are already a great steward of your home!

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