Is roof cleaning worth it?

When is a roof clean worth it?

A roof clean is worth it when moss, lichen or algae is building up on a roof that is otherwise in good condition. That covers most homes that ask about it. The usual signs are:

• Moss is spreading. Green patches are joining up, or moss is building up along the tile edges and around the ridge.
• The gutters keep filling. Clumps of moss from the roof are landing in the gutters and blocking them.
• You’re getting ready to sell. A roof covered in moss is easy to see from the street.
• You’d rather deal with it early. Light moss is easier to clear than a thick build-up.

Moss holds rainwater against the tiles and washes into the gutters and valleys, which is how it leads to problems over time. You can read more in our guide to whether moss damages roof tiles.

When isn’t a roof clean worth it?

A clean isn’t the right first step on every roof. It’s usually not worth paying for one when:

• The roof is failing. If tiles are cracked, slipping or missing across the roof, or there’s damp in the loft, get a roofer to check it first. Cleaning a damaged roof only makes it look better.
• The roof is near the end of its life. Most tiled roofs are expected to last several decades. If an old roof needs replacing soon anyway, the money is better spent on the new roof.
• There’s only a light dusting of moss. A little moss on a sound, steep roof isn’t urgent. Keep an eye on it each autumn and book a clean when it starts to build up.

Some companies also offer a roof coating after cleaning. It costs considerably more than a clean, so treat it as a separate decision.

How does the cost of a roof clean compare with repairs and a new roof?

A roof clean costs a small fraction of most roofing work. The table compares a Washmates roof clean with typical UK prices for common repairs and for re-roofing.

Typical UK prices for roofing work, checked October 2026. These are not Washmates prices, and published averages don’t always say whether VAT is included.

Re-roofing in clay tiles or natural slate costs more than concrete tiles, and scaffolding can add to any roofing job. A tile repair costs least when the tiles are easy to match and can be reached from a roof ladder; hard-to-find tiles or a job that needs scaffolding pushes it to the top of the range. A clean won’t stop a roof ever needing repairs, but clearing the moss early means the roof, gutters and valleys aren’t holding water for years before anyone notices. You can see typical roof cleaning prices by type of house in our cost guide.

How long does a roof clean last?

A roof that has been cleaned and treated with a biocide usually stays clear for two to four years. The biocide keeps working on the tiles after the clean, killing spores before they take hold.

Moss comes back sooner where the conditions that grew it haven’t changed. Roofs that are shaded, north-facing or under trees stay damp for longer, so they need cleaning sooner. Roofs in open, sunny spots last longer. Without a biocide, a roof can look green again within a year or two, which is why a cheaper clean can cost more over time. See how often you should clean your roof.

Does a clean roof help when you sell?

It can help, but be wary of anyone who puts a figure on it. There’s no reliable evidence for how much a clean roof adds to a sale price.

What is true is that buyers see the outside of a house first, and many form a view before they step inside. A buyer’s surveyor also looks at the roof, usually from the ground with binoculars, and rates its condition. Thick moss hides the tiles, so it’s harder for anyone to tell what state they’re in. A clean roof is easier to judge, and any real problems are easier to spot and deal with before a sale.

What do you get for the money?

A Washmates roof clean covers the whole roofline, not just the tiles. Every roof clean includes:

• The tiles, cleaned with a soft wash, then treated with a biocide to slow moss regrowth.
• The gutters, cleared, because moss washed off a roof often ends up in them.
• The fascias and soffits, the boards along the edge of the roof.
• Any solar panels on the roof, cleaned at the same time.

The work is done from roof ladders, scaffold towers or a cherry picker, normally by a team of two, or three on big jobs with a cherry picker. A three-bedroom semi usually takes a full day. To compare this with booking each job separately, see what it costs to clean a roof, gutters and solar panels together.

Does it matter how the roof is cleaned?

Yes. A soft wash uses a cleaning solution at low pressure and a biocide to kill moss at the root. A jet wash blasts the moss off with high-pressure water, which can crack older tiles, strip their surface and force water underneath them. Leading UK roof tile manufacturers advise against pressure washing.

That’s why a much cheaper quote isn’t always the better deal. You can read more in our guide to whether pressure washing damages a roof, and about the best time of year to clean a roof. If your roof is sound and the moss is building up, tell us about your roof and we’ll send you a fixed price, usually without a site visit.