What does a curling shingle actually mean?
A curling shingle means the asphalt has dried out. Ultraviolet light and heat drive the oils that keep it flexible out of the asphalt, and as it hardens it shrinks. A shrinking layer bonded to a mat that is not shrinking has to distort somewhere. That distortion is the curl.
A curled tab gives wind something to catch, and a stiffened tab can't seal back down to the course below. In Ottawa that's a January problem first: a lifted edge lets meltwater from an ice dam travel sideways and upward under the course above.
Cupping versus clawing
- Cupping: the edges of the tab turn up and the centre stays down, like a shallow dish. It commonly follows heat and moisture from the attic side, so it often shows up worst over rooms with poor airflow, over bathrooms, or on a slope that gets little wind.
- Clawing: the centre of the tab lifts while the edges stay flat. It is more often the mat itself expanding and contracting against the layer beneath it as the shingle ages.
What you fix depends on the shape. Clawing on an otherwise sound roof is aging, which is what a rejuvenating treatment addresses. Cupping from a hot, damp attic is a ventilation problem, and nothing we put on the outside changes what is happening underneath. Correct the attic first.
What does granule loss in the gutters mean?
Granules in your gutters mean the shingle is losing its ultraviolet protection. The mineral granules take the ultraviolet hit so the asphalt doesn't. Once coverage thins, sunlight reaches the asphalt, 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. Check the splash block after heavy rain, not the gutter trough, which 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.
- Flat, dark patches seen from the ground mean the granules are gone and you're looking at asphalt.
Ottawa speeds this up twice over. Spring melt flushes a winter of loosened granules through the gutters at once, which is why homeowners notice it in April and assume it happened overnight. Freeze-thaw cycles drive moisture into an already-dry shingle and 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 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, where accelerated aging starts, so a field of popped blisters will shed granules quickly from here on.
Bald patches
A bald patch is where the granules are gone and the mat or bare asphalt shows. Isolated spots on an otherwise intact roof are a condition note. Bald areas spread across a slope mean the shingle has lost its protective layer, and we cannot put that back by coating over exposed mat.
Moss and organic growth
Moss holds water against the shingle, and in Ottawa that water freezes, expands and lifts the shingle edge. It concentrates on north-facing slopes and under overhanging trees. Moss with visible root mass lifting tabs is structural. Black streaking is milder, generally algae rather than moss, and mostly appearance.
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. Brittle shingles crack under a footstep, loose granules behave like ball bearings under a boot, and dew and 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 not lying flat, colour gone dark and flat, and courses that are no longer straight.
- Sight along the roof from a corner of the property. Curl and waviness show up at a low angle and disappear 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 sheathing, damp insulation or a musty smell mean water is getting in, which moves the conversation from coating to repair.
- Find the age. The install date on the last roof's paperwork tells you more than most visual symptoms do.
Anything above ground level belongs to someone with fall protection. We inspect the roof free of charge and send you photographs, so you never have to go up yourself. Book the free on-site assessment.
What does each symptom suggest about remaining life?
No single symptom sets a roof life, but together they narrow the range quickly. None of it is a verdict 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 treatment 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 is solid and nothing is leaking. We only treat a roof that qualifies. If yours needs minor repairs, 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:
| 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 are life-extension figures, not warranty terms, and they say "up to" on purpose. 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. Granule loss is one of the signs that a roof is a Revive candidate, but the treatment works on the asphalt, not on the mineral surface. Water beads and runs off instead of soaking in, and the surface also reflects UV rays to limit heat absorption, slow aging and prevent discoloration.
It does not restore granules already in your gutters or reverse a crack. It slows the aging of a shingle that is still intact. More detail is 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 adds the least life of the three tiers in the table above, which makes it the entry tier.
That does not make it a bad buy. On an older roof where the alternative is doing nothing for another few seasons, that added life 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. 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, softening the asphalt no longer 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 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 first.
Even in the best case, a coating pushes the replacement further out. It does not cancel it. If you are weighing the two, the roof coating versus replacement comparison sets out where each one wins.
What does rejuvenation cost in Ottawa?
Published Ontario roofing price guides put a shingle replacement at $8,000 to $20,000 CAD in 2026. That is not a Protexa price. A treatment on a roof that qualifies is typically a fraction of it, fixed in writing after a free assessment.
We can't give a per-roof number here, because the same treatment on two houses on the same street can be different work. The estimate moves with size and pitch, shingle condition, how much granule loss and prep or minor repair there is, access and safety, and which of the three products suits it. The guide to what determines roof coating cost breaks each factor down. For a real number, book the free on-site assessment and we'll measure your roof with no obligation.
Common questions
How much granule loss is normal?
A small amount in the first year is normal shedding left over from manufacturing. After that, a steady deposit at the base of the downspouts on a roof more than about ten years old means sunlight is reaching the asphalt and drying it out.
Should I walk on my roof to inspect it?
No. Dried-out shingles crack under weight and loose granules roll like ball bearings underfoot. Use binoculars or a zoomed phone camera from the ground, check the downspouts and look inside the attic.
Does a roof coating fix attic ventilation problems?
No. If heat and moisture under the deck are making shingles cup, a coating treats the surface while the cause continues underneath. Ventilation and insulation are separate work. Fix them first, or the same damage returns.