Moss on Your Roof: Should You Remove It? (Sussex Homeowner's Guide)

Yes, in most cases you should remove moss from your roof. A little moss won't bring a roof down overnight, but left for a few years it keeps your tiles wet, pushes them out of place and washes into your gutters. It's easy to deal with if you catch it early, and the method you use matters as much as the timing.

Is moss on roof tiles a problem?

Moss isn't harmful in itself. The problem is what it does to a roof over time. It works like a sponge, so your tiles stay damp long after the rain stops. That leads to:

• Damp tiles. Constant moisture wears away the surface of concrete and clay tiles, and damp can reach the felt and timbers underneath.
• Frost damage. In winter, water held in the moss freezes and expands. Over time this can crack tiles or lift them, which lets rain in.
• Lifted tiles. Thick moss grows into the gaps between tiles and pushes them up, leaving openings for wind-driven rain.
• Blocked gutters. Clumps of moss break off and wash into your gutters and downpipes. Water then overflows down your walls. If that's already happened, our gutter cleaning service will clear them out.
• A tired-looking home. A mossy roof drags down kerb appeal, which matters if you're thinking of selling.

Why does moss grow on some roofs and not others?

Moss likes shade and damp. North-facing roofs, roofs under trees and roofs that get little sun usually grow moss first. Mild, wet winters in Sussex and South London give it plenty of time to spread.

Should you pressure wash moss off a roof?

We'd advise against it. High-pressure water can strip the surface off tiles, force water up underneath them and damage ridge tiles and pointing. It also leaves the roots behind, so the moss grows back quickly. Scraping by hand is gentler on the tiles, but it's slow, it means working at height, and it doesn't kill the roots either.

Softwashing is the safer option. It uses low pressure with a treatment that kills moss, lichen and algae at the root, so the roof comes clean without damage and stays clear for longer.

What's the best time of year to remove moss from a roof?

Summer and early autumn are usually best. Moss comes away more easily in dry weather, treatments work better when it isn't raining, and you clear the roof before winter frosts can do any harm. If moss is already lifting tiles or blocking gutters, though, don't wait for the summer.

Can you remove roof moss yourself?

You can, but working on a roof is dangerous without proper access equipment, and walking on tiles can crack them. If your roof is higher than a single storey, or the moss is thick, it's safer and quicker to call a professional.

How much does roof moss removal cost?

It depends on the size of your roof, how much moss there is and how easy it is to reach. As a guide, our prices start from £380 for a bungalow and £475 for a 3-bed semi. See our roof cleaning prices for the full breakdown.

Get your roof cleaned by Astound

Our roof cleaning service uses softwash and specialist treatments that kill moss at the root, across Sussex and South London. We'll survey your roof for free and give you a fixed price before any work starts.