Roof installation
A new roof, from tear-off to final sweep
Nanaimo Roofers installs new asphalt and metal roofs across the Regional District of Nanaimo. A full tear-off exposes the deck, so soft or rotten sheathing is found and replaced before any underlay goes down. Asphalt shingles need a slope of at least 1 in 3 under Table 9.26.3.1 of the BC Building Code.
A new roof is a sequence, and most of what decides how long it lasts happens before the first shingle is fastened.
What a tear-off exposes
Stripping to the deck is the only way to see the sheathing. Panels that have gone soft under a leak get cut out and replaced, and the fasteners holding the rest get checked. Underlay goes on next: asphalt-saturated sheathing paper or No. 15 felt, with head and end laps of not less than 50 mm, overlapping the eave protection by at least 100 mm. None of it is visible once the roof is on, which is why the photographs taken at this stage matter more than the ones taken at the end.
The slope decides the material
Table 9.26.3.1 sets a minimum slope for every roof covering. Asphalt shingles need 1 in 3, or 1 in 6 where the low-slope method is used. Profiled metal starts at 1 in 4 and has no upper limit. Modified bituminous membrane runs from 1 in 50 up to 1 in 4. The floor across the whole table is 1 in 50 — flatter than that and the job is a re-slope, not a re-roof. Measuring the slope first is what keeps a quote from changing halfway through.
Eave protection, and the exemption that applies here
Section 9.26.5.1 sets eave protection at 900 mm up the slope, carried to a line 300 mm inside the inner face of the exterior wall. Section 9.26.5.2 exempts regions with 3,500 or fewer degree-days. Nanaimo sits at 3,000. A second exemption applies again on asphalt shingles installed to Subsection 9.26.8, so most shingle roofs in the Regional District of Nanaimo are covered twice over.
Venting is not optional
Section 9.19.1.2 sets unobstructed vent area at not less than 1/300 of the insulated ceiling area, and 1/150 below a 1-in-6 slope or where the roof is framed with roof joists. It has to be split across opposite sides, with at least 25% at the top and at least 25% at the bottom. A roof vented only at the ridge moves no air, and the shingles above a dead attic age faster than the ones beside them.
What it comes to
Architectural asphalt runs $4 to $9 a square foot installed and lasts 25 to 30 years. Standing seam and profiled metal run $8 to $30 and last 40 to 70. The spread inside each range is the roof itself: dormers, valleys, penetrations, a second storey, and how much sheathing turns out to need replacing.
What's included
Asphalt shingle roof replacement
Standing seam metal installation
Roof deck and sheathing replacement
Attic ventilation correction
People also ask
How long does a re-roof take?
Most single-family roofs are a one to three day job once the crew is on site. A cut-up roof with several valleys, or one that needs sheathing replaced over a large area, runs longer. The scope names the expected number of days before the work is booked.
Can a new roof go over the old one?
Layering hides the deck, and the deck is where the failures start. Nanaimo Roofers strips to the sheathing so the underlay, the eave detail and the fasteners all land on sound material.
What happens if the sheathing is rotten?
The quote carries a per-sheet rate for replacement, agreed before the tear-off starts. Nothing about the price changes on the day except the count of sheets actually replaced, which is photographed.
Does the old roof get hauled away?
A bin lands before the tear-off and leaves with the old material. The property gets a magnet pass for fasteners before the crew leaves.
Keep exploring
- What a new roof costsInstalled price by material, and what moves it on a given roof.
- Permits by communityWho issues the permit for an address, and what each authority asks for.
- Where the work isThe communities covered across the Regional District of Nanaimo.
- Metal roof systemsStanding seam and profiled metal from a slope of 1 in 4 with no upper limit, detailed for a 2.1 kPa ground snow load and a 0.50 kPa design wind.
- Roof repair and leak tracingFlashing, valleys, penetrations and laps. Finding where water enters a roof, which is almost never directly above the stain on the ceiling.
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