Roof replacement in British Columbia, explained end to end.

Why coastal BC is hard on roofs

The Lower Mainland delivers long stretches of moderate rain rather than short violent storms. That favours moss, algae and slow-moving moisture problems over dramatic wind damage. Roofs here tend to fail at the details — valleys, flashing, and poorly ventilated attics — before the field of the roof wears out.

That is why a replacement in BC is rarely just new shingles. It is an opportunity to correct underlayment, flashing and ventilation so the next roof reaches its full service life instead of retiring early.

Choosing materials for wet winters

Architectural asphalt shingles remain the default: good value, widely stocked, and typically 25 to 30 years of realistic service on the coast when ventilation is right. Look for algae-resistant products, which meaningfully reduce the black streaking common in this climate.

Standing-seam metal costs considerably more up front but sheds water and moss well and can last 40 to 50 years or more. Cedar is traditional in parts of BC and beautiful, but it demands maintenance and faces fire restrictions in some municipalities. Low-slope sections over additions and carports usually need a membrane system rather than shingles.

What the job actually looks like

A proper replacement starts with protecting landscaping and setting up disposal, then a full tear-off down to the deck. Any soft or rotted sheathing is replaced — this is the most common change order, so ask for the per-sheet price in advance.

Then comes ice and water membrane at eaves, valleys and penetrations, synthetic underlayment across the field, new metal flashing (not reused), the roofing material itself, and ridge ventilation. Finally a magnetic nail sweep and a walkthrough with photos.

Budgeting realistically

Quotes vary widely because the scope varies widely. Rather than comparing bottom-line numbers, line the quotes up side by side and check that each one names the same underlayment, the same flashing replacement, the same ventilation work, and the same disposal and permit responsibilities.

Ask what the workmanship warranty covers and for how long, and whether the manufacturer's extended warranty requires a certified installer. On the coast, workmanship warranty length is often a better signal of quality than the shingle brand.

Getting a quote

TNS Contracting handles full roof replacements across the Lower Mainland and the western Fraser Valley, from Vancouver and the North Shore through Burnaby, Surrey and Langley out to Abbotsford. Send the details of your roof below and they will arrange an inspection and written quote.