Moss Removal for Your Roof

(Updated April 26, 2021)

You’ve just had a beautiful, functional roof installed, and you notice it beginning to grow moss. It may feel inevitable here in the Pacific Northwest, but that doesn’t mean it’s any less frustrating. Or maybe you find that moss adds character to your home, like the little cottage from a fairy tale.

Unfortunately, moss is more harmful than it may look. Moss removal and prevention are the keys to extending the lifespan of your roof. Moss absorbs gallons of water, then it grows roots. These roots get under your roof shingles over time, which creates open air space.

That allows moisture to get in. Once moisture is there, you can expect rot, leakage, and other big problems! This is why it’s important to remove moss as soon as you see it. There are certain steps to take to make this job as easy and painless as possible.

A Gentle Approach to Moss Removal

You may be tempted to take an overzealous approach in an attempt to rid your roof plane of moss. Whether you decide to brush or scrub your roof, it’s essential you don’t do it too harshly as that can damage your shingles. Remember, moss and algae are the enemy, not your roofing material.

The same is true of power washing. A pressure washer could chip cedar shingle roofs, remove granules that give your asphalt shingles strength, or allow water to become trapped underneath your roof. That is exactly what you are trying to prevent – you could be doing more harm than good.

Remove Moss From Your Roof

Instead of doing one massive cleaning every six months, preventative measures require a bit of proactive care. But it’s ultimately in the best interest of the long-term health of your roof. Which in turn means your home will be better protected from the elements.

The first step is to use a regular garden hose to wet the moss. Then, with a long-handled scrub brush, scrub gently down the roof to remove the moss. Never push back against the shingles – always scrub in the direction in which they are laid. You could put down some plastic sheeting for easier clean-up, too.

If you still can’t get the moss off, you’ll need to take some extra steps. In these cases, you’ll need to go to the hardware store. There are great spray cleaners for your roof – we recommend Bayer 2-in-1 Moss and Algae Killer, Wet & Forget, and Moss B Ware. You could make your own at home, too, with the right recipe.

You’ll want to wait for a cloudy day to get to work on this. The reason being, a sunny day will cause the cleaner to evaporate before it’s set in. When you’re ready, apply it on the roof, then gently scrub as you did before.

Cleaning moss is a seasonal job. If you are proactive, you can take steps that make it harder to grow. Both copper and zinc are toxic to roof algae and moss. You can install strips of either metal to the top ridge of your roof.

And, keep in mind that even if you just scrubbed your roof of dead moss, you may see moss problems again. Moss spores travel through the air – that’s how it got there in the first place. So you may want to pass this along to your neighbors! Because if they have moss, chances are you’ll get it, too.

Even though it’s damaging, moss can be removed easily. Make sure to be careful when doing so – moss can be quite slippery. Also, be careful when handling cleaning chemicals, such as oxygen bleach and other store-bought cleaning solutions. The process should be easy and painless and can save you tons in potential roof repairs down the road.

Other suggestions include:

  • Prune your trees – When you take a look at your roof, you’ll probably notice moss grows primarily in shaded areas on your roof. We aren’t advocating to chop all your trees down (please don’t do that!), but trimming or thinning out the branches allows for more sunlight to get through the canopy and onto your roof. This lets your roof dry more quickly, making it more difficult for moss to grow since moss likes damp, wet areas.
  • Keep your roof free of debris – Almost everyone’s roof has fallen leaves and twigs scattered around the shingles, and gutters frequently collect their own debris. What you might not know is that leaves and twigs provide nutrients for the moss, and make it easier for moss to spread and grow.
  • Look for algae-resistant materials – There are algae-resistant shingles, but those are normally installed when you’re getting a new roof altogether as part of a home improvement project. The good news is there are algae-resistant materials that don’t require an entirely new roof.

Roof Professionals in Vancouver, Washington

Keeping your roof looking like new can may be slightly more difficult in southwest Washington, but it’s definitely worth the effort. If you have questions about moss removal, new roof installation, or roof repair, give our team at Warner Roofing a call. With our expertise, friendliness, and professionalism, we are your resource for any questions you may have.

Moss on Tree in Vancouver WA
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