Are Roof Coatings Worth It? A Homeowner's Guide for Dublin, Lucan and Bray

Every autumn, homeowners around Dublin, Lucan and Bray get leaflets or a knock on the door offering to clean and "seal" their roof with a spray-on coating. The pitch usually sounds simple: wash off the moss, spray on a coloured coating, and the roof looks new and is protected for years.

Some coatings have a genuine place, especially on certain flat roofs. But on a typical pitched roof of concrete tiles or slates, a coating is rarely the fix it is sold as, and it can hide the problems that actually cause leaks. This guide explains what coatings can and cannot do, when a repair is the better spend, and how to check an offer before you agree to anything.

What a roof coating actually is

"Roof coating" covers very different products:

• Liquid-applied waterproofing for flat roofs. These are engineered systems (often polyurethane, acrylic or similar) applied in layers, sometimes with a reinforcing fleece, to form a continuous waterproof membrane. Good systems are tested and certified for specific uses.
• Decorative or "protective" coatings for pitched tiles. These are sprayed over concrete tiles after cleaning, mainly to change or refresh the colour and slow moss regrowth.
• Patch products. Brush-on sealants sold for small cracks, flashings or gutter joints. These are short-term holding repairs, not a roof covering.

Treating all three as the same thing is where many problems start.

Why a pitched roof does not need a "seal"

A tiled or slated roof is not designed to be watertight on its surface. Tiles and slates overlap so that rain runs off, and the underlay below catches any wind-driven rain that gets past them. Laps, ventilation gaps and the way water drains between tiles are part of how the roof works.

Problems we see after cosmetic coatings on pitched roofs include:

• Leaks still happening, because the real cause (a slipped slate, a cracked ridge tile, failed lead flashing, a torn underlay, a blocked valley) was never fixed.
• Defects being hidden. A fresh coat of colour makes it harder for a roofer to spot cracked or porous tiles later.
• Damage from the cleaning stage. High-pressure washing can crack older tiles, force water under laps and wash out mortar on ridges and verges. We cover safer options in our guide to moss on roof tiles.
• Tiles and slates that are harder to repair. Matching a single replacement tile to a coated roof can be awkward, which matters on roofs that already need matching replacement tiles.

Natural slate roofs in particular should not be coated. If a slate roof is failing, the usual answers are slate repairs, refixing slipped slates, or planning a re-slate.

When a coating can make sense

There are situations where a coating is a reasonable option:

For flat roofs, the honest comparison is usually between a coating, an overlay or full replacement, and a proper membrane such as EPDM or GRP. Our felt, EPDM and GRP comparison explains those options.

Ask for certification and a written specification

If a coating is proposed for your roof, ask which exact product and system will be used, and whether it has independent certification for that use.

In Ireland, NSAI Agrément certifies construction products and systems against the Building Regulations, and its certificates can be searched online. For example, NSAI has certified liquid and hot-applied roof waterproofing systems such as the IKO Permaphalt roof waterproofing system, with conditions about how and where it is installed. Some products carry certification from the UK's BBA instead. Either way, a certificate covers a specific product used in a specific way, so check that the use on your roof matches.

A useful written quote should state:

• the product name and system, not just "roof coating";
• what preparation and repairs are included before coating;
• how many coats, and the thickness or coverage;
• what happens at flashings, upstands, outlets, gutters and edges;
• what the guarantee covers, who provides it, and what conditions apply.

If a guarantee is offered, ask whether it comes from the product manufacturer or only from the installer, and what happens if the company stops trading. See our guide to roof warranties for more.

Doorstep offers: your rights in Ireland

Roof coatings are often sold by cold-calling traders, sometimes with pressure to "start today" or a "special price if you sign now". Take your time.

The Competition and Consumer Protection Commission (CCPC) says that if you sign up to a service on your doorstep, you have a cooling-off period of 30 days from when you agree the service contract. Before you buy, the business must give you its name, physical address, phone number and email, the total price and any extra charges, and information about your right to cancel. If a business does not tell you about your right to cancel, the CCPC says the cancellation period can be extended to up to 12 months. Read the CCPC's page on cancelling a service or contract for the full details.

Practical checks before agreeing to any roof work at the door:

• Get the full company name, a physical address and a landline or verifiable phone number.
• Ask for a written quote and specification, and compare it with at least one other roofer.
• Do not pay a large cash deposit on the spot.
• Be wary of anyone who says your roof is "dangerous" and must be done today, but will not show you clear photos of the problem.
• Ask for photos of the roof before and after any work.

Our roof repair quote checklist has more questions worth asking.

Coatings and energy grants

Some sellers suggest a coating will make your home warmer or cut heating bills. Coatings on top of tiles are not roof insulation. If heat loss through the roof is the concern, look at attic insulation and ventilation instead. The SEAI offers grants for attic insulation carried out by registered contractors, and the grant amounts depend on your home type, so check the current figures on the SEAI website before you plan the work. Our guide to attic insulation and roof ventilation explains why ventilation matters when insulation is added.

What we would check instead

Before spending money on a coating, a roof survey from the ground, from a ladder at the eaves, from inside the attic, or by drone where suitable, will usually tell you more. We look at:

• slipped, cracked or porous tiles and slates;
• ridge, hip and verge mortar or dry-fix systems;
• lead flashings at chimneys, walls and roof windows;
• valleys and gutters, including blockages and joints;
• the underlay and signs of damp or daylight in the attic;
• on flat roofs, the deck, falls, outlets, blisters and edge details.

Please do not climb onto your roof to check it yourself. Wet tiles, moss and Irish winter wind make roofs dangerous, and walking on tiles or slates can cause more damage. Photos taken from the ground or from an attic hatch are enough for a first conversation; see which roof leak photos to send.

Quick decision checklist

• Roof leaking? Fix the cause first. A coating will not do it.
• Slate roof? Do not coat it.
• Faded but sound concrete tiles? A coating is a cosmetic choice. Check tiles and ridges first, and avoid high-pressure washing.
• Flat roof showing wear? Compare a certified liquid system with an overlay or replacement, based on the deck condition.
• Offer at the door? Get everything in writing, take your time, and remember your cooling-off rights.

Get honest roof advice in Dublin, Lucan and Bray

Perfect Roofing works across Dublin City, North Dublin, South Dublin, Lucan, Bray, Wicklow, Naas and nearby areas. If you have been offered a roof coating, or you are unsure whether your roof needs a repair, a coating or something else, send us a few photos and the quote you were given, and we will give you a straight answer.

Contact us by WhatsApp, call 083 066 3462, or email hi@perfectroofing.ie.