Is it worth sealing roof tiles?

There is no obligation, and whether it pays depends on the state of the roof. You gain most on a sound covering that darkens after rain and grows green: the sealer limits water uptake and makes the tiles more resistant to dirt.

Is one sealer suitable for both clay and concrete tiles?

Yes. VD-1 is made for both types of tile. On glazed or engobe tiles, test a small area first, because the sealed surface takes less product.

When can I seal the roof after washing?

Once the covering is completely dry. Pick a day with no rain in the forecast: VD-1 becomes rainproof after 5-6 hours.

How much sealer do I need for a roof?

With VD-1 it depends on how absorbent the tiles are, because it is applied to saturation: seal one square metre, measure what it took and multiply by the roof area with a small margin. ImperGuard Ultra 4 in 1 covers about 8 m² per litre. We show how to get from a trial metre to a number of cans in the guide how much sealer do I need.

Will a sealer refresh the colour of old roof tiles?

No. VD-1 is colourless and does not change the look of the covering, and neither does ImperGuard Ultra 4 in 1. Sealing protects the tiles from water, but it will not bring back faded colour.

Roof tile sealer and roof cleaner

Type of tile: VD-1 is made for clay and concrete roof tiles. Glazed and engobe tiles have a sealed surface and will take less product - test them with a drop of water: if it soaks in, the tile will benefit from sealing.
Vapour resistance: VD-1 has a water vapour diffusion resistance of Sd = 0.0 m. After sealing, the covering offers no resistance to vapour at all, and the tiles keep their appearance.
Roof and wall together: If one product is to cover the roof, the facade and the paving, choose ImperGuard Ultra 4 in 1 - a litre covers about 8 m².
Condition of the roof: A sealer protects a sound roof but does not repair it. Replace cracked tiles and get a roofer to fix any leak before you reach for the product.

3 products

Guides

Before you choose: how to pick the right product, prepare the surface and what to expect once it is on.

Roof covered in red ceramic clay tiles, close-up of the tile rows

Choosing a product

Sealing roof tiles - when it pays and how to do it

A sealer limits how much water roof tiles absorb and makes them easier to keep clean, but it only works on a washed, dry and intact roof. The order of work, clay versus concrete tiles, and what sealing will not fix.

September 29, 20269 min read

Clay roof tiles overgrown with moss and algae above rows of freshly washed, clean tiles

Stain removal

Cleaning moss off roof tiles - how to wash a roof and what with

Moss, algae, soot and leaf marks come off roof tiles with a cleaner, but rooted moss has to be scraped off first. How to tell the growth apart, what dilution to use by hand and with a pressure washer, and what to do with the gutters afterwards.

September 30, 20269 min read

Weathered brick and mineral-render facade with a faint old damp line

Choosing a product

Facade and roof sealers

A wall comes with a condition a driveway does not: masonry has to give up moisture. Which makes vapour permeability the first question here, not the last.

September 17, 20264 min read

On a roof, a sealer does one thing: it limits how much water the covering takes up. A tile that absorbs less dries faster after rain, is easier to wash and picks up dirt more slowly, and on concrete tiles sealing also reduces the risk of efflorescence. You will find every product for walls and roofs in the Facades and roofs section.

VD-1 or ImperGuard Ultra 4 in 1

VD-1 - a water-based water-repellent sealer made for roof tiles. It penetrates deeper than 5 mm and meets PN-EN 1504-2. You apply it to saturation in one thicker, even coat, so consumption depends on how absorbent the tiles are - measure it on a trial square metre.
ImperGuard Ultra 4 in 1 - colourless, forms no film and leaves the covering vapour-permeable. At 8 m² per litre, a 5-litre can covers about 40 m² - handy when the same product is also going on the facade and the driveway.

A roof covered with bitumen shingles is a different job - bitumen coverings take the EI-25 restorer.

Order of work on the roof

Scrape out moss rooted in the joints and laps with a plastic scraper or a stiff brush, working from top to bottom. The cleaner works on the surface and will not pull out rooted moss.
Wash the roof with C-11D roof tile cleaner: 30-50 ml per litre of water for light growth, 80-100 ml/l for moderate and 200-300 ml/l for heavy. Leave it for 15-20 minutes and rinse with clean water. Details are in the guide to cleaning moss off roof tiles.
Wait until the covering is dry not just on the surface but in the pores too.
Apply VD-1 with a soft roller, a brush or a sprayer and plan for 5-6 hours without rain. We cover choosing the product and applying it in the guide to sealing roof tiles.

The most common mistake

Rinsing from below. A jet directed under the laps drives water beneath the covering instead of washing it off. Always work from top to bottom, following the way the tiles are laid, and on a cool roof - in the morning or evening, never in full sun.

Questions before you choose

Is it worth sealing roof tiles?: There is no obligation, and whether it pays depends on the state of the roof. You gain most on a sound covering that darkens after rain and grows green: the sealer limits water uptake and makes the tiles more resistant to dirt.
Is one sealer suitable for both clay and concrete tiles?: Yes. VD-1 is made for both types of tile. On glazed or engobe tiles, test a small area first, because the sealed surface takes less product.
When can I seal the roof after washing?: Once the covering is completely dry. Pick a day with no rain in the forecast: VD-1 becomes rainproof after 5-6 hours.
How much sealer do I need for a roof?: With VD-1 it depends on how absorbent the tiles are, because it is applied to saturation: seal one square metre, measure what it took and multiply by the roof area with a small margin. ImperGuard Ultra 4 in 1 covers about 8 m² per litre. We show how to get from a trial metre to a number of cans in the guide how much sealer do I need.
Will a sealer refresh the colour of old roof tiles?: No. VD-1 is colourless and does not change the look of the covering, and neither does ImperGuard Ultra 4 in 1. Sealing protects the tiles from water, but it will not bring back faded colour.