Understanding And Repairing Fish Mouthed Asphalt Shingles

Posted on: 29 July 2016

Asphalt roofs are the most common and popular types of roofs due to the low cost and availability of the materials. Asphalt will last some time as well, but you will generally notice some telltale signs of damage across your business if your roof is left in place for longer than 30 years. The fish mouthing of shingles is one fairly apparent sign of wear and tear. Keep reading to learn what fish mouthing is and how you can deal with the problems.

What is Fish Mouthing?

Fish mouthing is a term used to describe the curling or buckling of asphalt shingles. This curling appears in the middle of each shingle and the damage looks like the mouth of a fish. Fish mouthing typically occurs when the joints or spaces between the shingles start to disappear. The shingles then butt up against one another when they expand. This causes the buckling to occur in the middle of each of shingle. Wet weather conditions cause the shingles to expand, and the asphalt becomes less pliable over time. This means that older shingles will be unable to constrict after they contract. This leads to both the disappearing of the spaces between the shingles and the permanent appearance of the fish mouthed materials.

In some cases, the fish mouthing can occur when the shingles remain wet for a long period of time. This happens if moist air gets underneath the shingles and makes them wet. Typically, the felt underneath the shingles will wick the moisture away from the shingles. This helps to keep the shingles and the plywood dry. However, if the felt is not thick enough or if outdoor conditions are too humid or wet, then the felt will be unable to remove all the moisture.

Shingles that appear fish mouthed and do not flatten when they dry out may be brittle. Much of the asphalt or bitumen will already have evaporated from the roofing materials. This means that you should not directly walk on the shingles to inspect them. The tabs are likely to break away and leave only the adhesive edge behind, and leaks can occur in the area. These shingles may need to be replaced, especially if they are already ripped or torn. If the issue has just started to appear though, then you may be able to fix the problem.

How Can The Issue Be Fixed?

If you have just started to see shingles fish mouthing across your business's roof, then you may be able to stop further damage from occurring. Some shingles may flatten a small amount if they are allowed to dry out completely. You may not be able to control the outside humidity, but you can reduce indoor moisture. Moisture will rise through the roof sheathing from the attic or upper level of your business. If moisture levels are high enough in your business, then the water vapor can contribute significantly to the drenched nature of the roofing felt. You can start to resolve the roofing issue by placing a dehumidifier in your attic or upper level space. Consider the size of the area and the moisture level when looking at dehumidifiers. A moist area that is also spacious may require a unit that removes up to 70 pints of water from the air in a 24 hour period. 

Roof vents may also be needed if the dehumidifier does not reduce the fish mouth shingle issue. Speak with a commercial roofing professional about where the vents should be added and how many need to be placed around the roof. 

The warped shingles may start to bend down but remain buckled a small amount. If you notice this, then you can place a small amount of adhesive underneath the buckled area and press the shingle down flat. Use roofing cement for this purpose. 


A Direct Guide To Roofing

Hi, my name is Scott, and as you search through this blog, you'll learn invaluable information concerning roofs. When reading the articles, you'll learn about roof repairs, roofing materials and what's new in the roofing industry. I didn't become interested in roofing until my roof started to leak. When that happened, I started doing all types of research to find out why and where my roof was leaking. As I performed my research, I became very interested in the entire industry and even after I hired professional roofers to fix the leak, I still wanted to learn more about roofing. Since I enjoy blogging in my spare time, I decided to start a blog about roofing, and I hope that you also find the information you read interesting and useful.