After a windstorm you look up at your roof to examine if there is any damage. You do not see any missing shingles. Your house looks ok, your neighbors houses look ok, but you are noticing a few areas where the shingles appear to be curved and not really laying flat. Thoughts fill your head, “Could this be storm damage?? Or is this just normal aging of my roof?”.
People in general don’t spend time examining their roofs until after a storm occurs. Many things you see could very well have been there long before, but never have caught your attention. You should always have a professional roofer or inspector take a look at your roof if you think there is damage, but here are a few explanations for what you may be seeing.
1. Fishmouthing- This occurs when a shingle is sticking up in the middle or at the edge. When the roof is installed some nails can be over-driven or under-driven into the roof decking. Overtime, with the expansion and contraction that occurs with wood with the heat and cold, the nail works its way out of the roof decking. It pushes up on the shingle and makes it appear like a bump. Eventually it will go through the shingle and become what is called a nail pop.
When you see this occurring on your roof, the best method of roof repair is to hammer the nail back into the decking until it is secure. You can nail on top of the roof shingle. If the nail has come through and created a hole, put a dab of roof tar or clear silicone caulk over the hole in the shingle to stop any potential roof leaking.
2. You see a hump in the roof, it looks like a budging line down the roof shingles. - A common misconception is that the wind blew up the plywood from the attic. This is unlikely. Typically, this occurs when the plywood sheets used for the roof decking was installed right up against each other. When installing the roof decking, the framers should leave a small space between the boards. This space is to allow expansion and contraction of the sheets of plywood. When the boards are pushed up against each other, they do not have room for any movement. The two pieces of sheeting expand and but up against each other pushing the boards upward. This shows up as a hump on the roof.
There really is no way of fixing this until the roof shingles are torn off and the plywood can be trimmed down. The good news is that it should not cause any leaking from the roof. This hump was slowly forming ever since the roof was installed, now that you have noticed it you will see it all the time, but probably not from the windstorm.
3. Cracking- Shingles can be cracking on the body of the shingle, or vertical cracks up the roof. Cracking on the body of the shingle is from aging. You may see one area that is cracking more than the rest of the roof, it could just be a defective bundle of shingles. Millions of bundles of shingles are manufactured every year and some are not perfect. Yes, the cost of the materials are under warranty (not the labor) but unless it is leaking you probably would be better served just to leave it until the roof is replaced.
Vertical cracking occurs from a manufacturing defect in the roof shingles or from expansion and contraction of the plywood. This time instead of the plywood bulging up like a hill, it shifts like tectonic plates in an earthquake. The shingles are not as strong as the wood, so they tear in a vertical form up the roof.
Vertical cracking is not related to a windstorm. Sometimes this can be extreme and allow water to enter. This may be a case where at some point the shingles in that area need to be removed to trim down the wood and re-shingle that area.
These roof damages are typically unrelated to a storm event, and in the examples above, would not be covered under a standard homeowners insurance claim. These are just a few examples of roof damage not caused by a hurricane or windstorm, but you can never be too sure and call out a roofing professional to take a look.