Roofing · asphalt shingles
Asphalt shingle roofing: new roofs, re-roofing and repairs
Asphalt shingles are the roof on most houses and many strata buildings in the Lower Mainland. We inspect the roof, the deck and the details before we price anything, and tell you whether it needs a repair or a new roof.
What a shingle roof is
Layers that shed water, not a sheet that holds it.
A shingle roof works by shedding water. Overlapping courses of asphalt shingles sit over an underlayment on the roof deck, starting at the eave and finishing with a cap along the ridge. Flashings carry the water past every place the roof meets something else: walls, chimneys, skylights and vents. Ventilation in the roof space below keeps the deck and the underside of the roof dry.
The assembly for each roof is set after the inspection: the underlayment, the shingle product and its manufacturer, and the flashing and ventilation details. It is written into the proposal, so you know exactly what is going on your roof before work starts. Shingles need enough slope to shed water; the minimum slope and the underlayment for it come from the shingle manufacturer and the BC Building Code, and a roof flatter than that needs a membrane roof instead.
When it fits
New roofs, re-roofing and repairs on pitched roofs.
| The roof | What it usually needs |
|---|---|
| Shingles curling, cracking, losing granules or missing across the roof | Re-roofing: the old shingles off, the deck checked and repaired, a new shingle roof |
| A few missing or damaged shingles on an otherwise sound roof | A repair of the damaged area and the flashings round it |
| Leaks at a chimney, skylight, wall or vent | Flashing repair or replacement at that detail |
| A new house or addition with a pitched roof | A new shingle roof to the specified assembly |
| A roof or a section too flat to shed water | A membrane roof: torch-on or liquid-applied |
Inspecting the existing roof
What we check before we price a shingle roof.
| Where we look | What we are looking for |
|---|---|
| The shingles | Curling, cracking, missing tabs, granule loss and moss |
| Valleys | Worn or open valleys, and debris holding water |
| Flashings | At walls, chimneys and skylights: lifted, rusted or missing pieces |
| Penetrations | Plumbing and exhaust vents, and how each one is sealed |
| Eaves and gutters | The drip edge, the gutters, and water getting behind them |
| The deck | Soft spots underfoot, sagging, and rot wherever it can be seen |
| Ventilation | Intake and exhaust for the roof space, and signs of condensation |
| Inside | Stains and drips, and how soon after rain they show |
Where the shingles have failed across the roof, a new roof is the honest answer. Where they are sound, a repair at the valley, the flashing or the vent is usually what the roof needs, and we will say so.
Details
Most shingle-roof leaks start at a detail.
The field of a shingle roof rarely leaks first. Valleys, where two slopes meet and carry the most water; the flashings at walls, chimneys and skylights; and the boots round plumbing vents are where water gets in. On a new roof every one of them is rebuilt; on a repair, they are usually the first thing we look at.
Our wet coastal winters add two more: moss, which holds water against the shingles and lifts their edges, and moisture in the roof space when the ventilation is not doing its job. Both are looked at in the inspection, and the ventilation is part of the scope on a new roof.
Scope and schedule
What sets the price and the timing.
The size and pitch of the roof; how many layers come off on a re-roof; the condition of the deck once it is exposed; the valleys, flashings, chimneys and skylights; access for materials and for the disposal of the old roof; and how the building is being used while the work goes on. We do not give a fixed price or a duration before the roof has been inspected.
Weather sets the rest. Shingles go on in dry weather, and on a re-roof the old roof only comes off as fast as the new one can be made watertight behind it.
Shingles or a membrane roof
The pitch decides.
Shingles are for pitched roofs. Flat and low-slope roofs, and the flat sections between pitched ones, take a membrane: a new torch-on roof, or a liquid-applied restoration where the existing roofing is still sound. Many buildings have both, and one inspection covers the whole roof. The roofing page sets out all three.
Questions we get asked
Asphalt shingle roofing FAQs
Do you replace whole shingle roofs, or only repair them?
Both. A few damaged or missing shingles, or a leaking flashing on an otherwise sound roof, is a repair. Shingles that are curling, cracking or losing their granules across the roof mean a new roof. The inspection decides which, and the proposal says why.
Can new shingles go over the old ones?
Sometimes a second layer is allowed, but it depends on the existing roof, the deck, the shingle manufacturer and the BC Building Code. We usually recommend taking the old shingles off, because it is the only way to see and repair the deck, and the proposal states which way the roof will be done.
Which shingles do you use?
The shingle product, its manufacturer, the underlayment and the flashing and ventilation details are set for each roof after the inspection and named in the written proposal, so you know exactly what is going on your roof before work starts.
Is our roof steep enough for shingles?
Shingles shed water, so they need enough slope to do it. The minimum slope, and the underlayment needed near it, come from the shingle manufacturer and the building code. A roof or a section flatter than that needs a membrane roof instead, either torch-on or liquid-applied.
Do you work on strata buildings and townhouse complexes?
Yes, as well as houses and the sloped roofs of commercial buildings. On a strata complex the work is planned with the council and the property manager, building by building, so residents know which roof is being done and when.
How is a shingle roof priced?
After an inspection. The size and pitch of the roof, how many layers come off, the condition of the deck, the valleys, flashings, chimneys and skylights, and access set the price, so we do not quote a blind rate per square foot.
Roof inspection request
Tell us about the roof.
The more of this you fill in, the more useful our first reply. If water is coming in right now, call (604) 968-2040 instead — that is faster than any form.
Keep reading
Related pages
Roof assessments
Send us the roof. We’ll tell you what it needs.
Photographs and an address are enough to start. We inspect the roof and tell you whether it needs a repair or a new roof.
Main (604) 968-2040
Second (604) 230-0256
estimating@westpacificcoatings.com