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ROOFING INSPECTION & REPAIR
AMERICAN CEMWOOD ROOFING
BEST ROOFING PRACTICES
BUILT UP ROOFS
CATHEDRAL CEILING VENTILATION
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY FLASHING Mistakes & Leaks
COLD WEATHER ROOF TROUBLE
DECKS, ROOFTOP CONSTRUCTION
EPDM, RUBBER, PVC ROOFING
EXTRACTIVE BLEEDING on SHINGLES
FIRE RETARDANT PLYWOOD
FLASHING on BUILDINGS
FLAT ROOF MOISTURE & CONDENSATION
Green House or Solarium Roof Leaks
HEAT TAPES & CABLES on Roofs for Ice Dams
ICE DAM PREVENTION
MASONITE WOODRUF FIBERBOARD ROOFING
NOISE CONTROL for ROOFS
PLASTIC ROOFING TYPES
PVC, EPDM, RUBBER ROOFING
ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
ROOF CLEANING RECOMMENDATIONS
ROOF COLOR RECOMMENDATIONS
ROOF DORMER TYPES - PHOTO GUIDE
ROOF INSPECTION SAFETY & LIMITS
ROOF JOB PROBLEMS, RESOLVING
ROOF LEAK DIAGNOSIS & REPAIR
ROOF NOISE TRANSMISSION
ROOF REPLACEMENT SNAFUs
ROOFING FELT UNDERLAYMENT REQUIREMENTS
ROOFING MATERIALS, Age, Types
ROOFING TILE SHAPES & PROFILES
ROOFING UNDERLAYMENT BEST PRACTICES
SADDLE CONSTRUCTION at CHIMNEYS
SNOW GUARDS & SNOW BRAKES
STANDARDS for ROOFING
STRESS SKIN INSULATED PANELS
TEST LABS - ROOF SHINGLE
TREES & SHRUBS, TRIM OFF BUILDING
TRUSSES, Floor & Roof
UNDERLAYMENT REQUIREMENTS on ROOFS
VENTILATION in BUILDINGS
WALK-ON ROOF SURFACES
WARRANTIES for ROOF SHINGLES
WORKMANSHIP & ROOF DAMAGE
ZINC METAL ROOFING
This website tells readers how to identify & explain the asphalt shingle roof wear pattern known as "fishmouthing" or "fishmouthed roof shingles".
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
An example of the less-than-fully-waterproof back of asphalt roof shingles is seen in our photos of "fishmouthed" roof shingles. In these cases a specific "curling" pattern of shingles called "fishmouthing" displays a raised shingle edge which looks a lot like a fish's open mouth. These shingles are not curled over at the very edge.
Inadequate Venting and High Building Moisture Cause of Asphalt Shingle Fishmouthing
Fishmouthed cupping of asphalt roof shingles is caused by excessive under-roof moisture such as by a poorly or un-vented attic or roof cavity. Moisture escaping through the roof sheathing and up through the bottom of the shingles contacts the uppermost shingle which spans the butt joint of shingles below, placing more moisture at that point on the shingle tab than elsewhere. This uneven moisture, probably combined with weather exposure, leads to a raised, cupped "fishmouth" look on those shingles.
Shingles are not quite waterproof: You may not realize it but asphalt roof shingles are not quite waterproof and in particular the back side of asphalt shingles is much less water resistant than the upper or exposed side. The exposed side of an asphalt shingle is protected from sun damage by a coating of mineral granules. These shingles rely on the pitch of the roof and mechanical drainage combined with proper placement or pattern of shingling on the roof to avoid leaks. [This photo courtesy of Carl Gerosa, New Rochelle, NY.]
Shingle Fishmouthing is a Building Diagnostic Aid
Fishmouthed Asphalt Roof Shingles under light snow cover - an Ice Dam, Leak, Mold, Rot Warnings
Fishmouthed Asphalt Shingles are Vulnerable to Damage
As we suggested in the cased of other cupped, curled, or fragile asphalt roof surfaces, we would stay off of fishmouthed-shingle roofs, particularly in cold weather (when the fishmouthed roof shingles are more likely to break). If we have to walk on a fishmouthed shingle roof, tiptoe carefully, avoiding stepping on the raised or fishmouthed shingle sections.
Do Fishmouthed Asphalt Shingles Need Replacement?
If the shingles are not damaged, broken, cracked, or showing other signs of wear, it may be possible to leave these shingles on the roof longer than otherwise. That's because this fishmouth pattern can show up earlier in shingle life on a wet building with poor under-roof venting. An experienced inspector or roofer can point out the extent of roof damage and other shingle wear signs that will decide if the roof is ready to be replaced.
Question about early asphalt roof shingle failure:
I live in Wisconsin and had my roof replaced (total strip down) about 6 years ago. Now my shingles are curling up or fish mouthing. I do not know what you call it but it looks terrible . Can you help me out? A friend said to check on the internet for something with Owens Corning.
I believe they are 30 yr shingles. I do not have any of the paper work but when they put them on they said they only use premium shingles. Check out the rain gutter. It is 3/4 full of shingle fragments and granules. The rest of the roof shingles still look good. Any help would be great. - Louis Tolley, Adams WI
Answer and advice on diagnosing a failing fishmouthed shingle "new roof" job:
The roof shingle wear pattern in your photos is easily mistaken for "fishmouthing asphalt roof shingle" but what we see in your photos is not "fishmouthing" but rather shingle curling, combined with extreme granule loss.
Comparing Shingle Fishmouth Patterns with Shingle Curling Patterns
Fishmouthing asphalt shingles appear as an upwards curve in the center of shingle tabs, usually where the center of a fishmouthed shingle tab crosses over the shingle butt joints in the course below. See the fishmouth shingle photos above on this page.
Shingle tab curling, such as shown in your photos, occurs at the corners of shingle tabs, not in the center of the tab. See CURLING ASPHALT SHINGLES.
How old is This Roof Wear-Out?
Regardless, your roof photos show severe wear and curled shingle tabs that we see at the end of roof life - your photos of this worn roof slope show that every single shingle tab is curled up from a corner – that combined with the significant granule loss would be very unusual on a six-year-old roof. We comment further and provide some roof failure diagnostic questions just below.
From looking at the photographs, and recognizing that we are not looking at the entire roof, some comments and questions arise that should help sort out this "early roof failure" mystery:
Six-Year-Old Roof Shingle Failure Diagnostic Questions
Watch out: First off - don't fall off the roof while you are up there looking around.
Don't walk on these fragile, damaged asphalt shingles - they'll break and leak.
Go back to look at your information on your 6 year old re-roof job with the questions listed below. If you have no records and no documentation of who did the roof, what was the contracted scope of work (all slopes or just some) we can still figure this out by inspection of the whole building.
Usually when we have inspected early roof failure cases like this it turns out that there was a misunderstanding (or less often, dishonesty) - the roofer did not re-shingle all slopes, maybe just one of them, but the owner thought they all were being done.
Frequently Asked Questions (FAQs) about the fishmouth curling pattern on asphalt roof shingles: causes, cures, prevention
Questions & answers about the fishmouth curling pattern on asphalt roof shingles: causes, cures, prevention.
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ASPHALT ROOF SHINGLES