Looking without climbing
These defects are spotted from the ground, with binoculars if you have them. The ones that cannot be seen from below, like a badly placed nail, we find on site. You do not climb on the roof or up a ladder. Take dated photos to show us during the visit.
On shingle roofing, defects are sorted by their origin.
Asphalt drying out
The sun dries the asphalt over the years. The shingle stiffens, shrinks a little and changes shape.
- Bare patches. The shingle looks smooth and darker in places, and sand the colour of the roof piles up at the foot of the downspouts.
- Cracks. They cut across the shingle and often line up from one course to the next.
- Deformed shingles. Corners curl up or the middle rises in a bump. A poorly ventilated, overheated attic speeds up the deformation.
These signs generally come with age. On a young roof, there is a cause to find: insufficient ventilation, moisture in the attic or a manufacturing defect.
What the wind carries off
Wind grabs the roof by its edges: rakes, ridge and the bottom of the slopes.
- A missing shingle. It leaves a rectangle of another shade, that of the underlayment or the course below.
- A shingle that no longer sticks. Its adhesive strip has let go. It flaps with every gust, then breaks along its nails.
What goes back to the installation
Some defects go back to the installation and owe nothing to age.
- A nail in the wrong place. Driven too high, it goes through only one thickness. Driven too deep, it goes right through the shingle.
- A popped nail. It lifts the shingle covering it, then pierces it. The installation may be the cause, or the wood moving.
- A flashing replaced with tar. Around a chimney, a smeared coating is no match for metal pieces and lasts only so long.
What grows on it
Black streaks on the north slope are algae, a mostly cosmetic matter. Green cushions are moss, which holds water against the shingle and can lift its edges.
When the roof line is no longer straight
From the street, a slope should be flat and the ridge taut. A slope sagging between two rafters, or a wavy ridge, signals that the wood under the shingles is affected. We then have to open the roof to measure the damage.
One spot or the whole slope
The extent of the defect decides what comes next. A branch fallen on a corner, a few shingles blown off along an edge, a crack at the foot of a vent: the defect is in one spot and the rest of the roof is sound. A repair is enough.
When the same signs cover a full slope, or all of them, the shingles have aged at the same pace. Redoing one area only postpones the next call.
Age completes the picture. According to manufacturers and the quality of the installation, an asphalt shingle lasts on the order of 15 to 30 years. A roof at that point, with defects everywhere, is heading for a replacement. Ask the roofer, who must hold a licence from the Régie du bâtiment du Québec (RBQ, Quebec's building authority), whether the problem is local or widespread.
Frequently asked questions
Does the roof need to be redone for three or four damaged shingles?
No, not when the other shingles are still flexible, covered with granules and lying flat. We then replace the affected pieces. Redoing everything is worth discussing when a whole slope is affected or repairs keep coming.
My roof does not leak. Can it still be worn out?
Yes, a roof can be worn out without leaking. Under worn shingles, the underlayment and the overlap of the courses stop water for a while. Waiting for the first leak exposes the deck and the insulation.
Are these defects covered by the manufacturer's warranty?
The manufacturer's warranty generally covers a manufacturing defect, under conditions, and often excludes normal wear or poor installation. Reread its text and keep your invoice. The installation falls instead under the roofer's labour warranty.