What does a curling shingle actually mean?
A curling shingle means the asphalt has dried out. It has lost the oils that keep it flexible, so the mat has started to move and the tab has changed shape. Ultraviolet light and heat drive the volatile oils out of the asphalt over time, and as the asphalt hardens it shrinks; a shrinking layer bonded to a mat that is not shrinking with it has to distort somewhere. That distortion is the curl.
A curled tab gives wind something to catch. A stiffened tab can't seal back down to the course below it, and in Ottawa that's a January problem before it's a July problem, because a lifted edge lets meltwater from an ice dam travel sideways and upward under the course above.
Cupping versus clawing
- Cupping is when the edges of the tab turn up and the centre stays down, so the shingle looks like a shallow dish. Cupping commonly follows heat and moisture arriving from the attic side, which is why it often shows up worst over rooms with poor airflow, over bathrooms, or on a slope that gets little wind.
- Clawing is the reverse. The centre of the tab lifts while the edges stay pinned flat. Clawing is more often about the mat itself expanding and contracting against the layer beneath it as the shingle ages, rather than about anything happening in the attic.
What you fix depends on which shape you have. Clawing on an otherwise sound roof is an aging problem, and aging is what a rejuvenating treatment addresses. Cupping driven by a hot, damp attic is a ventilation problem, and nothing we put on the outside will change what is happening underneath. If the attic is the cause, correct the attic first.
What does granule loss in the gutters mean?
Granules in your gutters mean the shingle is losing its ultraviolet armour. The mineral granules on top take the UV hit so the asphalt doesn't, and once coverage thins, sunlight reaches the asphalt directly, it dries out faster, and the shingle moves toward brittleness and curl.
How we read what you find:
- A cup or so in the first year after installation is normal shedding of loose granules left over from manufacturing.
- A steady deposit at the base of every downspout on a roof past about ten years is the signal that matters, so check the splash block after heavy rain, not the gutter trough, because the trough holds granules from years ago.
- Loss concentrated in one strip usually has a mechanical cause: runoff from a valley or an upper roof, a downspout discharging onto shingles, or the path your snow rake takes every winter.
- Darker patches seen from the ground are the same story from above, and where the colour has gone flat and dark, the granules are gone and you're looking at asphalt.
Ottawa adds two accelerants. Spring melt flushes a winter of loosened granules through the gutters at once, which is why homeowners notice this in April and assume it happened overnight. Freeze-thaw cycles drive moisture into the surface of an already-dry shingle and then expand it, loosening the granule bond faster than a milder climate would.
What do blistering, bald patches and moss tell you?
Blistering, bald patches and moss are three different warnings. Blistering and moss can sit on a roof that is still a candidate for coating; bald patches spread across a slope cannot.
Blistering
Blisters are small raised bubbles in the shingle surface, caused by moisture or gas trapped in the asphalt expanding under heat. Intact blisters are cosmetic. A popped one leaves a small crater with no granules in it, and craters are where accelerated aging starts, so a field of popped blisters is a roof that will shed granules quickly from here on.
Bald patches
A bald patch is an area where the granules are gone entirely and the mat or bare asphalt is visible. Isolated bald spots on an otherwise intact roof are a condition note, but bald areas spread across a slope mean the shingle has already lost the layer that protects it, and we cannot put that back by coating over exposed mat.
Moss and organic growth
Moss holds water against the shingle instead of letting it run off. In Ottawa that water freezes, expands and lifts the shingle edge. Moss concentrates on north-facing slopes and anywhere overhanging trees keep the roof shaded and damp, while black streaking is a related but milder issue, generally algae rather than moss, and mostly appearance. Moss with visible root mass lifting tabs is structural.
A treated surface resists dirt, grime and organic growth going forward. We remove existing moss during prep rather than coating over it.
How do you inspect a roof safely from the ground?
Do not walk an aging asphalt roof. The shingles you are trying to assess are dried out and brittle, so they crack under a footstep and you damage the roof you came to look at. Loose granules on a slope behave like ball bearings under a boot sole, and morning dew and overnight frost keep an Ottawa roof slick well past sunrise for much of the year. Falls from roofs cause serious injuries every season.
You can do all of it from the ground or on an attic joist:
- Photograph each slope with binoculars or a phone camera at full zoom. Look for tabs that are not lying flat, colour that has gone dark and flat, and courses that are no longer straight.
- Sight along the roof from a corner of the property, not straight on. Curl and waviness show up at a low angle across the surface and disappear when you look at the roof face-on.
- Check the base of every downspout after rain. That is where current granule loss collects.
- Go into the attic on a bright day with the lights off. Daylight through the deck, dark staining on the underside of the sheathing, damp insulation or a musty smell all mean water is getting in, and any of those moves the conversation from coating to repair.
- Find the age. If you have paperwork from the last roof, the install date tells you more than most visual symptoms do.
Anything above ground level should go to someone with fall protection, so we inspect the roof free of charge and send you photographs of what is up there. You never have to go look yourself. You can book the free on-site assessment here.
What does each symptom suggest about remaining life?
No symptom by itself sets a roof life, but together they narrow the range quickly, and none of it is a verdict on your roof until we've been up a ladder and looked.
| What you see | What it usually means | Where it usually leads |
|---|---|---|
| Light granule shedding, shingles flat, colour even | Early surface aging, shingle still flexible | Good candidate for a protective coating before damage starts |
| Clawing, steady granule loss, colour going flat | The asphalt has dried out and stiffened | The core rejuvenation case, if the shingles are still whole |
| Cupping concentrated over one part of the house | Heat and moisture from the attic side | Ventilation assessment first, surface treatment second |
| Popped blisters, scattered bald spots | Accelerated local aging, protection already lost in places | Depends entirely on how much of the field is affected |
| Cracked-through tabs, missing tabs across the field, bare mat over large areas | The shingle has failed, not aged | Replacement |
| Staining or daylight visible in the attic, soft deck | Water is already getting in | Repair or replacement, not coating |
Is my roof a candidate for rejuvenation?
A roof is a candidate when the shingles are dried out and shedding granules but are still structurally whole: the tabs are present, they flex without cracking, the deck underneath is solid and nothing is leaking. We check that on site at no charge. We only treat a roof that qualifies. If yours needs minor repairs and still qualifies, we handle those first and clean the surface as prep, and the coating goes on in a single day.
Which product suits your roof depends mostly on its age. We work from three tiers:
| Roof age | Product | What it is for | Life extension |
|---|---|---|---|
| Under 5 years | GoNano NuRoof Fortify | Protecting a roof that has not started to degrade yet | Up to 20 years |
| 6 to 20 years | GoNano NuRoof Revive | Restoring a weathered roof that is still sound | Up to 12 years |
| Generally 15 years or older | GoNano NuRoof Boost | Older roofs that no longer score high enough for Fortify or Revive | Up to 10 years on a full treatment |
Those figures say "up to" on purpose. They are life-extension figures, not warranty terms. GoNano issues a manufacturer's warranty of 3 to 20 years. The term depends on the Roof Health Score GoNano assigns your roof at the assessment and on the number of coats applied. That warranty also requires a certified GoNano contractor to apply the treatment. PROTEXA Property Services is one.
What does NuRoof Revive actually do to a weathered shingle?
GoNano NuRoof Revive for aging asphalt shingle roofs, 6 to 20 years old. It penetrates deep into the shingle to rebuild flexibility and reinforce structure, and creates a hydrophobic barrier that protects against water, algae and surface erosion. It adds up to 12 years of roof life. It puts flexibility back into asphalt that has hardened. Granule loss is one of the signs that a roof is a NuRoof Revive candidate in the first place, but the treatment works on the asphalt, not on the mineral surface. The treated surface is hydrophobic, so water beads and runs off instead of soaking into the shingle, and it also reflects UV rays to limit heat absorption, slow aging and prevent discoloration.
It does not restore granules that are already in your gutters. It does not reverse a crack. It slows the aging of a shingle that is still intact. We go through the treatment in more detail on the Revive shingle rejuvenation page.
Where does NuRoof Boost fit, and where does it fall short?
GoNano NuRoof Boost for older asphalt shingle roofs, generally 15 years or older. A cost-effective treatment formulated with GoNano's nanotechnology and renewable bio-oils, it adds up to 10 years of functional roof life on a full treatment. It is the option for roofs that no longer score high enough for Fortify or Revive, and suitability is decided by the Roof Health Score GoNano assigns your roof at the assessment. It is the entry tier of the three. The added-life figures say so: up to 20 years for NuRoof Fortify, up to 12 years for NuRoof Revive, and up to 10 years for NuRoof Boost on a full treatment. NuRoof Boost is generally for roofs 15 years or older, where the roof no longer scores high enough for Fortify or Revive.
That does not make it a bad buy. On an older roof where the alternative is doing nothing for another few seasons, up to 10 years of added functional roof life on a full treatment is a real outcome. Just know what you are buying. NuRoof Boost buys time on an older roof; NuRoof Revive restores a weathered one.
When is rejuvenation the wrong answer?
Rejuvenation is the wrong answer whenever the roof has already failed rather than aged, and we will tell you that before we quote. Walk away from a coating if any of these apply:
- The roof leaks, or the attic shows staining, damp insulation or daylight through the deck. Water is already past the shingles, and a surface coating does not seal an active leak path.
- The deck is soft, sagging or rotted. That is structural work and it has to be opened up.
- Shingles crack instead of flexing. If a tab snaps when lifted, the mat is past the point where softening the asphalt helps.
- Tabs are missing across the field. A few blown tabs are a repair. Losses across multiple slopes mean the seal strips have given up generally.
- Large areas of bare mat are showing. There is nothing left to protect there.
- The damage came from a storm. Hail bruising or wind damage may be an insurance claim, and coating over it can complicate that claim. Get it assessed as damage first.
- Cupping traces to attic ventilation. Fix the cause, or the same damage returns to a coated roof.
Even in the best case, a coating extends the service life of a shingle roof and pushes the replacement further out. It does not cancel the replacement. If you are weighing the two paths against each other, the roof coating versus replacement comparison sets out where each one wins.
What does rejuvenation cost in Ottawa?
We can't give you a per-roof number here. The same treatment on two houses on the same street can be different work. The estimate moves with the roof: size and pitch, the condition of the shingles, how much granule loss there is, how much prep and minor repair it needs first, access and safety on the property, and which of the three products suits it. The guide to what determines roof coating cost breaks each factor down, and for a real number, book the free on-site estimate and we'll measure your roof with no obligation.
Common questions
Can rejuvenation fix curling shingles?
Partly. Rejuvenation can rebuild flexibility in shingles that have curled because the asphalt dried out, and it slows the drying that caused the curl. It cannot undo a shingle that has cracked through, lost its tabs or exposed bare mat, and because curling is a symptom with several causes, PROTEXA inspects the roof before saying whether a coating is the right answer.
How much granule loss is normal?
In the first year, a small amount of loose granules is normal shedding from the manufacturing process. After that it is not normal. Granules collecting steadily at the bottom of the downspouts on a roof more than about ten years old means ultraviolet light is reaching the asphalt underneath, and that dries the shingle out and makes it brittle.
What is the difference between cupping and clawing shingles?
Cupping is when the edges of a shingle turn upward and the middle stays down, so the tab looks like a shallow dish. With clawing the middle of the tab lifts while the edges stay flat against the roof. Cupping usually points to heat and moisture reaching the shingle from the attic side, while clawing usually points to the shingle mat aging and moving against the layer beneath it.
Should I walk on my roof to inspect it?
No. An aging asphalt roof is the worst kind of roof to walk on, because dried-out shingles crack under weight and loose granules behave like ball bearings underfoot. Inspect from the ground with binoculars or a phone camera at full zoom, check your gutters and downspouts, and look at the underside of the roof deck from inside the attic. Leave anything above ground level to someone with fall protection.
When is a shingle roof too far gone for a coating?
A roof is past coating once it has failed rather than aged. That means active leaks, a deck gone soft or rotted, shingles that crack through instead of flexing, tabs missing across the field rather than in one spot, or large areas of bare mat. In those cases the correct work is replacement. A coating slows the aging of a shingle that is still whole. It does not rebuild one that has failed.
Does a roof coating fix attic ventilation problems?
No. If shingles are cupping because heat and moisture are building up under the roof deck, a coating treats the surface while the cause continues underneath. Ventilation and insulation are separate work from coating. Fix them first, or the same damage returns.