For most sound roofs, a coating isn’t needed. Tiles are made to cope with the weather on their own. A coating is mainly a cosmetic choice that refreshes the colour of old, faded concrete tiles. It won’t repair a failing roof, and if someone says yours will fail without one, get a second opinion.
What is a roof coating?
A roof coating is a paint-like product sprayed onto clean roof tiles, usually concrete tiles, to give them a new colour and finish. It’s normally sold as the step after a roof clean: clean, treat, then coat.
Does a roof need a coating to protect it?
A sound roof doesn’t. Concrete, clay and slate roofs are designed to stand up to the weather without any coating. Their job is to shed water, and a clean, intact tile does that well. What protects a roof is sound tiles, sound fixings, good flashings, a working underlay and clear gutters.
So what is a coating actually for?
Mostly looks. Concrete tiles lose their surface colour over the decades. When a 40-year-old concrete roof is cleaned, the tiles underneath can look pale and patchy compared with when they were new. A coating gives them a single, even colour again. That’s a fair thing to want, but it’s a cosmetic choice, like painting a house.
When might a coating make sense?
- You have old concrete tiles that are sound but badly faded, and you want the roof to look newer.
- You want to change the colour of the roof (check first whether you need permission; see below).
- You understand that the coating itself will weather and eventually need maintaining.
When is a coating a bad idea?
- On a roof that needs repair. A coating over broken tiles, failed mortar or a leaking roof hides the problem; it doesn’t fix it.
- On clay tiles and slate. Their colour and texture is the point, and coating them is rarely a good idea.
- On listed buildings or in conservation areas, where changing the look of the roof may need consent.
- When you’re being rushed. A decision about your roof can wait a week.
Do coatings stop moss coming back?
A freshly coated surface is smooth, so growth may be slower to take hold at first. But coatings weather too, and moss and algae will return to a shaded roof eventually. A biocide treatment every so often does a similar job of keeping growth down, for far less.
What should I ask before paying for a coating?
- Is my roof sound without it? If yes, what exactly am I paying for?
- What product is it, and what does the manufacturer say about how long it lasts and how it should be maintained?
- What happens to the coating as it ages? Will it need redoing?
- What preparation is done first, and are any repairs needed before coating?
- Can I have it in writing, with time to think it over?
Do I need permission to change my roof colour?
In many cases, no, but there are exceptions. Listed buildings need listed building consent for changes to their character, and homes in conservation areas or under an Article 4 direction may have extra controls. If in doubt, check with your local council’s planning department before any work.
Watch out for pressure selling
Roof coatings are sometimes sold on the doorstep or straight after a clean, often with a deadline or a scary claim about the roof failing. A genuine tradesperson will give you a written quote and time to decide. If you’re told your roof will fail without a coating, get a second opinion from an independent roofer. Our post on roof cleaning cold callers has a checklist.
How long does a roof coating last?
That depends on the product and the roof, and the honest source is the manufacturer’s own information for the exact product being offered, not a salesperson’s estimate. Ask for the product name and look it up. Be wary of very long figures that aren’t in writing.
Can a coating cause problems?
It can if it’s the wrong product or it’s badly applied. A coating that bridges the gaps between tiles or traps moisture in old, porous tiles can cause more trouble than it solves. That’s another reason to ask exactly what product is being used and why it suits your roof.
Is a coating the same as a biocide treatment?
No. A biocide kills moss, lichen and algae and soaks into the surface; it doesn’t change the colour of the tiles or form a layer on them. A coating is a paint-like layer that sits on the tiles. They’re often mentioned together, but they do completely different jobs.
What do we suggest instead?
For a sound roof: a gentle clean, a biocide finish and a treatment when growth starts to come back. That keeps the roof clean, keeps its surface intact and costs far less over the years than coating and recoating.
Can a roof be coated later if I change my mind?
Yes. A clean and treatment now doesn’t stop you choosing a coating in future. Going the other way is harder: once a roof is coated, the coating has to be looked after for the rest of its life. Starting with a clean and seeing how the roof looks is the lower-risk order.
In short
- A sound roof doesn’t need a coating.
- Coatings are a cosmetic choice for faded concrete tiles.
- Never coat over damage.
What we do
We clean and treat roofs. We don’t push coatings. When we quote, we’ll tell you honestly whether your roof is sound, whether it needs a roofer, and what a clean will and won’t do to how it looks. More on our approach on the roof treatment page.
