Are algae-resistant shingles worth it? Black streaks on shingles in Vancouver

Dark streaks on roofs are a familiar sight in this city. It rains here a lot, especially from fall through spring. In Vancouver, asphalt shingles can stay damp for weeks, and that’s exactly what algae needs to grow and leave dark stains. Plenty of homeowners spot the streaks and think their roof is on its way out.

Dark streaks are usually algae. They don’t mean the shingles are breaking down. Moss is another matter, though, and you’d handle it differently. Before you book a cleaning or price out a new roof, find out which one you have. Flat black streaks point to algae. Raised green clumps mean moss.

Are algae-resistant shingles worth it? They are worth a close look for many Vancouver roofs. That goes double for a roof that stays damp under trees or in the shade. We can’t promise the same result on every house. What we can do is show you the exact shingle and its warranty, so you can see in writing what the algae coverage includes.

What Those Dark Streaks Actually Are

The dark streaks are generally blue-green algae. The spores are blown by the wind from roof to roof. They settle and spread in damp and humid weather. It’s a stain that spreads over a few seasons into the streaks on the roof you can see from the street.

Streaks don’t necessarily indicate a failure of the shingles. Plenty of people figure it’s just a looks problem, and a lot of the time they’re right. Still, you can’t tell for sure from the driveway or from a photo. Someone has to get up close and check the shingles. A roofer can do that check for you. They can also help with maintenance or a roof installation down the road.

How Algae-Resistant Shingles Work

These shingles have copper granules mixed into the top layer. Copper is something algae can’t stand. Rain does most of the work here. It pulls a bit of copper out of the granules and spreads it down the shingles. Algae doesn’t like that, so it struggles to take hold, and the dark marks take longer to appear.

CertainTeed’s StreakFighter® shingles work this way, with copper-containing granules blended into the surface. Scotchgard Protector is the blend Malarkey uses. Its product pages feature 3M copper granules to resist algae. The two brands aren’t the same. Warranty terms vary by product line. CertainTeed says algae coverage is product-specific. Malarkey backs its Scotchgard shingles with a limited lifetime algae warranty. And that covers blue-green algae only.

Keep your expectations real, though. These shingles cut down on streaks. They can’t promise you’ll never see one.

Streaks and Moss: Two Different Problems

Algae just sits on the surface as a stain. Moss is different. It’s a living plant that grows into thick green or brown clumps and soaks up water like a sponge. Over time, it can push up the edges of shingles and let rain get underneath.

One thing people miss: the copper in these shingles does nothing for moss. If you’re comparing asphalt shingles in Vancouver and your roof sits in shade, plan for moss on its own. Read our guide on moss on roofs to learn about the risks and removal options.

What It Means for Your Next Shingle Roof

Picking asphalt roofing shingles is about more than colour. Before you settle on one, look at these four things:

1. Deck condition: Have your roofer look at the wood under the old shingles. If it’s soft or rotten, a roof repair may not be enough, and you could be looking at a full roof replacement.
2. Product details: Get the data sheet for the exact shingle you’re being quoted, not just the brand name.
3. Colour: Look at full-size samples outside in daylight. A small chip indoors can look quite different on a whole roof.
4. Care and warranty: Ask what upkeep the manufacturer expects. Some warranties can be affected if the roof isn’t cared for the way they say.

Shade, Trees, and Roof Orientation

Shade keeps a roof wet longer. Branches drop leaves and needles that retain moisture. Slopes that receive little sun dry slowly. Any of these can increase the chances of growth. None of them alone dictates the outcome. A sunny roof can still streak. A shaded one can stay clean. A roofer visiting your property can point out what keeps your roof damp.

Reading the Algae Clause in a Warranty

Ask for the written warranty on the specific shingle. Then slowly read the algae part. Check the type of algae involved. Check your coverage period. See what the maker will do for streaks. See what could void the claim.

Algae coverage is limited. And it does not guarantee a stain-free roof. If the wording is unclear, ask your roofer to explain it before you sign. It also shows you how they plan to handle the job. When considering asphalt shingles in Vancouver, homeowners should review their available options carefully. GoodVans Roofing can help with residential roof installation and replacement across Metro Vancouver. The expert roofers answer questions about shingle products and warranties.

Keeping Any Shingle Roof Cleaner for Longer

Twice a year check your roof from the ground. Binoculars are a help. Check for new streaks, green patches, curling, and missing shingles. Clean gutters. Pruning back overhanging branches can help to improve the flow of light and air up to the roof.

Don’t scrub vigorously. Pressure washers can remove the granules and force water under the shingles. Avoid harsh chemicals unless approved by the shingle manufacturer.

Seeing moss, or stains that keep spreading? Call an asphalt shingle roofing contractor in Vancouver, BC. They’ll check the roof up close and tell you what’s worth doing now and what can wait.

Why Choose GoodVans Roofing?

GoodVans Roofing is a CertainTeed SELECT ShingleMaster™ certified asphalt shingle roofing contractor serving Vancouver and the wider Metro Vancouver area. Our team handles roof installation, plus roof repair and maintenance, with solutions suited to the region's rainy weather, strong winds, and cool winters.

We'll inspect your roof first. Our team assesses its condition to help identify the likely cause of the streaks. Then, we'll discuss repair or replacement options. We’ll tell you whether algae-resistant shingles suit your roof and show you real shingle samples. Request a free estimate through our website or contact GoodVans Roofing for advice or a roof inspection.

Frequently Asked Questions

1. Do algae-resistant shingles stop moss?

No. Algae resistance is for dark staining only. Moss is a plant that grows where the roof is damp and shady, and it needs a separate plan.

2. Are black streaks harmful to a roof?

Often they are merely cosmetic. They can still show up alongside real problems. Look for granule loss, curling, moss, and missing shingles. If you see any of those, get an inspection scheduled.

3. Do algae-resistant shingles cost more?

It depends. Price is dependent on product line, roof size, pitch, access, and installation needs. CertainTeed characterizes the added cost of its algae-resistant versions as nominal. Your written quote is the only real number.

4. How should streaks be cleaned without damaging shingles?

Follow the shingle-maker’s cleaning directions. Do not use pressure washers, stiff brushes, or scrapers. It is not safe to walk on a wet roof either. If you are in any doubt, get a roofer to check.

About the Author

This guide was written by the GoodVans Roofing Team. We’re a CertainTeed SELECT ShingleMaster™ contractor, and we install, repair, and replace asphalt shingle roofs across Metro Vancouver. We write these guides to answer the questions homeowners, landlords, and property managers ask us, in plain words.