Should I coat my roof or replace it?
Coat the roof if the shingles are worn but intact, replace it if they have failed. The rest of this page is how you tell which one you have. A nano coating restores and protects material that is still doing its job. It cannot put back a shingle that has lost its mat, it cannot dry out a rotted deck, and it cannot close a hole that water is already coming through.
The two options are not close in scale. One is a day of maintenance; the other rebuilds the outside of your house. We see Ottawa homeowners quoted for a full tear-off on a roof with years left in it, and we see roofs treated that should have come off.
What makes a roof a strong candidate for coating?
A strong candidate is a roof that is losing its surface but has not lost its structure. Walk the perimeter of the house, look at the roof from the ground with binoculars if you have them, and look for these signs.
- Shingles still lie flat. Edges and corners sit down against the course below rather than lifting away from it.
- Colour has faded but the surface is continuous. Dull, chalky or unevenly coloured shingles are a surface problem, and surface problems are what coatings are for.
- Granules are thinning, not gone. Some grit in the eavestrough after a heavy rain is normal wear. Bare black asphalt showing through in patches is not.
- No active leaks. No staining on attic sheathing, no damp insulation, no ceiling marks.
- The deck feels solid. No sag between rafters, no soft spots, no daylight through the sheathing when you look from inside the attic.
- One layer of shingles. A single layer leaves the option of replacement genuinely open later, which is what a coating is buying you time for.
This is why we start with a free on-site assessment. We get on the roof, check its condition and photograph it. If it qualifies, we handle the minor repairs and clean the surface before anything is applied, and the coating goes on in a single day. If it does not qualify, we tell you. Not every roof passes.
When is roof replacement the right call?
Replace the roof when the shingles have stopped being a weather barrier, because no coating restores a barrier that is already breached. Any one of these findings on its own is usually enough for us to tell you to get replacement quotes.
- Structural deck damage. Sagging between rafters, spongy sheathing underfoot, rot around chimneys or valleys. The problem is under the shingles, so treating the shingles changes nothing.
- Widespread cracking or curling. Isolated curling at a hot south-facing edge is one thing. Cracking and cupping across whole slopes means the asphalt has lost its oils throughout and the shingles are brittle.
- Missing or blown-off shingles across multiple areas. Once wind is taking shingles off in more than one place, the fasteners and the mat are failing, not just the surface.
- Active leaks at more than one point. A single flashing leak is a repair. Several separate leak paths mean the assembly is done.
- Bare mat showing. Where granules are gone entirely, the asphalt beneath is exposed to UV directly and degrading fast. Nothing applied on top reverses that.
- Two or more existing layers. A previously over-roofed deck is already carrying more weight and more heat than it was built for, and the condition of the original layer cannot be assessed from above.
None of this is an argument against coatings. Coating a roof in this condition spends money that should have gone toward the replacement you need anyway. A coating delays replacement on a roof that is still sound. It does not cancel replacement on a roof that is not.
Which option matches my shingle age and condition?
Age narrows the product choice, condition decides whether coating is possible at all. Here is how we match the three roof products to roofs by age band and by condition.
| Shingle age | What you are seeing | Usual answer |
|---|---|---|
| Under 5 years | Sound, full granule coverage, no visible wear | GoNano NuRoof Fortify. Protection applied before damage starts, on a roof that has nothing wrong with it yet. |
| 6 to 20 years | Faded colour, some granule loss, shingles still flat and sealed | GoNano NuRoof Revive. Penetrates deep into the shingle to rebuild flexibility and reinforce structure. |
| Generally 15 years or older | Weathered and dull but intact, no leaks, deck solid | GoNano NuRoof Boost. NuRoof Boost is generally for roofs 15 years or older. It is the option for older 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. |
| Any age | Missing shingles, bare mat, widespread cracking, multiple leaks, soft deck, or two existing layers | Replacement. Coating is not an option and no assessment will change that. |
If you are reading your own roof and are not sure what a symptom means, the companion guide on curling shingles and granule loss works through the signs one at a time and where each one lands you.
How much life does each option actually add?
A coating adds years to the roof you already have; a replacement starts a new roof's service life from zero. Those are different purchases, so do not compare them as if they were the same one.
- GoNano NuRoof Fortify: up to 20 years of added roof life.
- GoNano NuRoof Revive: up to 12 years of added roof life.
- GoNano NuRoof Boost: up to 10 years of added functional roof life on a full treatment.
- Replacement: a full new service life, plus the shingle manufacturer's own warranty on new material.
Two things to be clear about. Every one of those numbers is "up to". That is what the product can add to a roof in good condition, not a figure we promise on every roof we look at, and the warranty term is a separate, shorter number that depends on the Roof Health Score. And a GoNano treatment is a single application, not an annual maintenance product. Have the roof reassessed every 10 to 15 years to decide whether a retreatment is worthwhile.
How disruptive is each option, and how long does it take?
A coating goes on in one day with nothing removed from your house; a replacement is a multi-day job that strips the roof to the deck.
With a coating there is no tear-off, so there is no dumpster on the driveway, no nails in the lawn, no exposed deck overnight and no window during which weather can get into the building. The sequence is assessment, then prep and any minor repairs, then application. With a replacement the roof is opened, which means scheduling around the forecast, protecting landscaping, and living with the noise of a full crew for several days.
Ottawa's calendar constrains both. Coatings need surfaces that are dry and above freezing, so the working season runs from spring melt to the first hard frost, and the shoulder weeks at either end book out first. Decide in November and you're usually deciding for next spring, so get the free assessment done early rather than in the middle of a January thaw.
What does an Ottawa winter do to an aging shingle roof?
Two things in an Ottawa winter do the damage: freeze-thaw cycling works water into shingles that have gone brittle, and ice damming holds standing water against the eaves where it has time to find a way in. Neither is a summer problem, and both get worse as shingles age.
An aging asphalt shingle has lost oils and granules, so it absorbs water instead of shedding it. Water in a shingle freezes, expands, and opens the crack it is sitting in a little further. Ottawa does that repeatedly through the winter and again through every thaw. By March a shingle that started the season merely faded can be genuinely cracked. Meanwhile snow melting off a warm upper roof refreezes at the cold eave, builds a dam, and backs meltwater up under the courses.
Act in the year you first notice the wear, not the year after. Water soaking into a dried-out shingle is the failure that freeze-thaw exploits, and the coating we apply leaves the surface hydrophobic, so water beads and runs off instead of soaking in. It works on a shingle that is still whole. Once the cracks are open, you are in the replacement column.
What happens to warranties, resale and insurance?
A coating does not void your shingle manufacturer's warranty. GoNano has confirmed this through a legal assessment covering the leading shingle manufacturers, including IKO, Owens Corning, BP and GAF. Alongside that, 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.
On resale, the warranty transfers with the house, so a buyer inherits the remaining term. Be straight with a buyer about what it is. A coating has kept a serviceable roof serviceable. It does not change the age of the shingles, and a home inspector will record that age from the roof itself.
On insurance, it varies. Some insurers recognise a coating and some do not, so ask yours directly. If it helps the conversation, under UL 2218 impact testing one treatment takes a Class 1 shingle to Class 3, and two treatments take it to Class 4. How many coats your roof gets is specified at the assessment.
What determines the price of each option?
Both options are priced off the same physical facts about your roof, which is why we will not quote either one from a photograph. What drives the number is size and pitch, the current condition of the shingles, how much granule loss there is, how safely the roof can be accessed, how much prep and minor repair is needed before work starts, and which product tier the roof calls for.
A steep roof takes longer and costs more to work on safely than a walkable one of the same area. A roof that needs flashing attention before a coating goes on carries that work with it. A replacement adds tear-off, disposal, underlayment and any deck repair that only becomes visible once the old shingles are off, which is why replacement quotes so often move after the roof is opened. The guide to what determines coating cost goes through each of these drivers in detail.
We quote after looking at the roof, not before. The assessment is free, it carries no obligation, and it is available across Ottawa, Kanata, Nepean, Barrhaven, Orleans, Gloucester and Stittsville. Book the free on-site assessment and you will have a written number and photographs of your roof's actual condition to decide from.
Common questions about coating versus replacing
Is a roof coating a substitute for a new roof?
No. A nano coating extends the life of an asphalt shingle roof that is still sound; it cannot rebuild one that has failed. If shingles are missing, the mat is showing through, the roof leaks in more than one place or the deck underneath is soft, replacement is the correct answer and a coating would only postpone it at the cost of the money you would have put toward the new roof.
Can you coat a roof that is already leaking?
Not until the leak is found and fixed. A coating is a surface treatment: it resists water getting into shingles, it does not seal a hole in a roof assembly. The free on-site assessment exists to catch exactly this, and part of the process is handling minor repairs and cleaning the surface before any product is applied. A roof with active leaks at several points is usually past coating.
How old is too old for a roof coating in Ottawa?
Age narrows the choice of product but condition decides whether coating is possible at all. GoNano NuRoof Fortify is matched to roofs under 5 years old and GoNano NuRoof Revive to roofs 6 to 20 years old. NuRoof Boost is generally for roofs 15 years or older: it is the option for older 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. A 22 year old roof that still lies flat with even granule coverage can be a better candidate than a 12 year old roof on a hot south face that has already gone bare in patches.
How long does a roof coating take compared with a replacement?
The coating is applied in a single day once the roof has been prepped, with no tear-off, no dumpster and no shingles coming off the house. A full replacement is a multi-day job that strips the roof to the deck, exposes the building while it is open, and leaves debris and nails to clean up.
Does coating a roof affect resale or home insurance?
A coating does not change the age of your shingles, and a buyer's home inspector will still record that age, so treat a coating as maintenance that keeps a roof serviceable rather than as a substitute for the new roof a buyer may want. For insurance, ask your own insurer directly: whether a coated roof changes anything on your policy is a decision each insurer makes, and PROTEXA does not speak for them.
What happens if my roof does not qualify for a coating?
We tell you during the free on-site assessment, before anything is applied and before you have spent anything. Not every roof qualifies. The assessment includes photographs of the roof's current condition, so if the answer is that it needs replacing you leave the conversation with evidence you can take to a roofing contractor.
The short version
If your shingles are worn but whole, lying flat, holding granules and sitting over a solid deck, coating is very likely the better use of your money and the product is matched to the age of the roof. If shingles are missing, cracked across whole slopes, worn to the mat, leaking in several places, or sitting on a soft deck or a second layer, replace the roof and do not let anyone tell you a coating will fix it. Everything in between is what we look at during the free assessment. Read the roof nano coating service page if you want the detail on how the products are applied, or the page on shingle restoration with NuRoof Revive if your roof is in the weathered middle of that range.