Granules in the Gutters: How Much Shingle Granule Loss Is Normal?

Granule loss in Greater Victoria has a strong direction to it. South and west slopes in the sunniest parts of the region, Sidney, North Saanich's Dean Park and the Esquimalt and James Bay waterfront, bake through July and August when the Gonzales station records only about 14 mm of rain, and those faces go bald years before the shaded north slope of the same roof. It is common to see a house where one slope is clearly due and the other looks fine, which complicates the repair-or-replace conversation.

The other local accelerator is cleaning. Moss is a fact of life under the Douglas fir and Garry oak canopy in Saanich, Highlands and Metchosin, and a roof that has been pressure-washed to remove it often shows a tell-tale pattern: granules gone in fan-shaped streaks that follow the wand. If a previous owner had the roof blasted clean, a roofer will usually want to know before promising the roof has years left.

The coloured mineral granules on an asphalt shingle are not decoration. They shield the asphalt from ultraviolet light, add fire resistance and give the shingle its weight and colour. A manufacturer's shingle comes with more granules than it needs, so a new roof sheds a modest amount for a season. Once the surplus is gone, the loss you see is the working layer, and every bare patch is asphalt drying out and cracking in the sun.

That is why granule loss is a leading indicator rather than a leak. The roof still sheds water, but its remaining life is shorter than the calendar age alone would suggest.

Everything useful here can be done from the ground or at the gutter outlet.

• Look at the splash block or the ground under each downspout for a sandy deposit; note how fast it rebuilds after cleaning.
• From the street or a neighbour's yard, use binoculars to compare the south or west slope against the north slope for shine or lighter colour.
• Ask the previous owner or your purchase inspection report whether the roof has ever been pressure-washed.
• Check the roof age from documents; local asphalt roofs last about 15 to 22 years by one Victoria contractor's 2026 estimate.
• Book an inspection ($150 to $400 in our pricing model, often credited against a later quote) if the roof is over 15 years.

There is no repair for granule loss itself; you cannot put the surface back. What a professional may do is confirm the roof's remaining margin and stop the accelerators: remove moss gently rather than by pressure, keep gutters clear, and make sure nobody walks the roof unnecessarily. If one slope is far worse than the rest, a section replacement ($800 to $2,500 in our pricing model for one slope area) occasionally makes sense on a younger roof, but colour matching on a faded roof is difficult and most roofers will be honest that it buys a few years at most.

For a roof past 15 years with bald patches on the sunny slopes, the realistic path is replacement planning in the next dry season. That gives you time to run the numbers, compare quotes and consider algae-resistant or heavier laminate shingles, or metal on a heavily shaded lot.

In our pricing model a 2,000 sq ft two-storey home in laminate asphalt is about $6,900 to $12,600 before GST, and the same floor area on one storey, with twice the roof, roughly $13,200 to $24,000. Published 2026 Victoria contractor guides put most single-family replacements between $9,000 and $30,000 across all materials. Because granule loss usually comes with a healthy deck, the decking allowance tends to be small on these jobs unless moss has been left for years.