Do Porcelain Tiles Need Sealing? Complete Guide

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Do porcelain tiles need sealing?

Do you need to seal porcelain tile? The short answer is possibly. Many porcelain tiles come pre-sealed and don’t need additional sealing, but it’s always best to check with the manufacturer. Generally, if the tiles come with a ‘nano seal’ they do not need to be sealed. You can also test yourself by jotting on an offcut with marker pen - if it’s easily removed with a bit of white spirit then it’s likely to be already sealed.

However, some porcelain tiles - such as polished porcelain - have micro-pores which can absorb water, so if you need them to be waterproof these will need sealing. If they’re exposed to the elements, are in a high traffic area or are being used in bathrooms, many installers like to seal the tiles to create an additional barrier for protection. It’s also recommended to use a grout sealer to prevent additional wear and tear.
 

What happens if you don't seal porcelain tiles?

Many types of porcelain tiles won’t need sealing, especially most glazed or porcelain slabs designed for outdoor use, as these are fired in a kiln at high temperatures to make them water resistant. However, if you use unglazed, highly porous or polished porcelain tiles these will need sealing to prevent water damage.

If the manufacturer recommends sealing the tiles, it’s essential to do so as soon as possible after installation. Unsealed tiles are porous and can let in water and oil, which can damage and weaken the tile. Unsealed tiles can also stain, and trap dust and dirt which can be difficult to clean. Unsealed grout can also lead to staining and damage to your floor.

Which sealant should you use for porcelain?

It’s best to choose a water-based sealer which is specifically designed for use on porcelain tiles, or a polyurethane topical sealer, as acrylics do not create a strong or long-lasting bond to such a dense surface. It’s important to choose a non-slip sealer if you’re using it on floor tiles.

With many different brands and finishes to choose from, the best porcelain tile sealer can be difficult to select. It is recommended to buy a sealer which is designed specifically for porcelain, and which won’t alter the appearance of the tile. You can choose matt or gloss, depending on the effect you want, and the best sealers double as a pre-grout sealer too.

Do outdoor porcelain tiles need sealing

Most porcelain tiles are certified to have a water absorption rate of less than than 0.5%, making them highly water resistant, so these won’t need sealing. However, polished porcelain and other specialist types of tile may need sealing as they are more porous and don’t offer the same level of water resistance. Installers recommend using a grout sealer for both tile types, to prevent stains, cracks and water entering.

Outdoor tiles are also more prone to mud, marks and cracks through more extreme temperatures. Sealing the tile can help to prevent this, though it’s not always essential and installers don’t always consider it necessary if you buy a particularly hard-wearing tile.

Tips for sealing porcelain tile

Generally, it’s a straightforward task to seal porcelain tiles, whether indoors or outdoors. Use a tile sealer specifically designed for porcelain and follow the manufacturer’s instructions to help protect your tiles and extend their lifespan.

Here are some other tips for how to seal porcelain tile:

Clean the tile before sealing

It’s vital to have a fully clean and dry tile and grout in order for the sealer to work correctly. Dirt and mud can become trapped as well, which makes the tiles look stained. 

• Remove any grease, oil, muck or pre-grout residue before starting

• Make sure the tile and grout is fully clean using a cloth or brush

• Leave surface and grout to dry before applying sealer

Apply the sealer evenly

Aim for a smooth, even application for the best finish. Once applied, any excess sealer should be wiped away to prevent unwanted residue.

• Use a paintbrush, pad or sealant smoother to apply sealer

• Apply an even layer and let it soak into grout lines

• After the first coat is absorbed, remove any excess with a clean cloth

Test and repeat the treatment

The sealer should create a waterproofing effect to protect the tile from moisture and debris. Often several coats are needed for hard wearing areas, bathrooms and patios.

• To test, put a few droplets of water on the tiles (the treatment is effective if the water stays on the surface and doesn’t soak in)

• Usually a 2nd or 3rd coat is recommended, leaving at least 30 minutes in between (or as per the label’s instructions)

• Repeat the waterproofing treatment if the water is still absorbed into the tile

Leave to dry before use

Most sealants can be walked on after a few hours, so light use is possible soon after application. It’s best to wait longer before using as normal in a shower or hallway.

• Leave it at least 24 hours before using in the shower or for getting the floor dirty

• Consider sealing the grout as well for extra protection for your floor or wall

Sealing porcelain tile FAQs
 

Do you need to seal porcelain tile?

The short answer is possibly. Many porcelain tiles come pre-sealed and don’t need additional sealing, but it’s always best to check with the manufacturer. Generally, if the tiles come with a ‘nano seal’ they do not need to be sealed. You can also test yourself by jotting on an offcut with marker pen - if it’s easily removed with a bit of white spirit then it’s likely to be already sealed.

What is the best sealer for porcelain tile?

With many different brands and finishes to choose from, the best porcelain tile sealer can be difficult to select. It is recommended to buy a sealer which is designed specifically for porcelain, and which won’t alter the appearance or colour of the tile. You can choose matt or gloss, depending on the effect you want, and the best sealers double as a pre-grout sealer too.

Do you seal porcelain tile or just the grout?

Most porcelain tiles are certified to have a water absorption rate of less than than 0.5%, making them water resistant, so these won’t need sealing. However, polished porcelain and other specialist types of tile may need sealing as they are more porous and don’t offer the same level of water resistance. Installers recommend using a grout sealer for both tile types, to prevent stains, cracks and water entering.

What happens if you don't seal porcelain tiles?

Most porcelain tiles won’t need sealing, as they are naturally robust and offer water resistance. However, if you have polished porcelain or other porous tiles they must be sealed to stop water from entering and damaging the tile. Unsealed tiles can stain, and attract dust and dirt which can be difficult to clean. Unsealed grout can also lead to staining and damage to your floor.

How long does porcelain sealer last?

Properly applied topical sealers can last for up to 5 years on your floor before needing to be reapplied. Impregnating sealers can last up to 15 years on walls. The best way to check is to test if water still beads up on the tile surface. If it’s no longer water resistant, you’ll need to seal the tiles again.

How often should you seal porcelain tiles?

Not all porcelain tiles need sealing, but for polished porcelain and other tiles you will need to seal them as soon as possible after installation, and ideally every few years afterwards - depending on how heavy the tiles’ use is. If you notice stains appearing or water being absorbed into the tile, the sealer should be reapplied.

How to seal porcelain tile

Generally, it’s a straightforward task to seal porcelain tiles, whether indoors or outdoors. Use a tile sealer specifically designed for porcelain and follow the manufacturer’s instructions to help protect your tiles and extend their lifespan.

• Clean and dry the tile and grout

• Apply the sealer evenly across tiles and grout

• Remove any excess before applying a second coat

• Leave to dry for several hours before walking on the floor

​​Please note: this is a guide only, so please always read the manufacturer’s instructions first.