Is Grout Waterproof?
27/01/2026
Tile grout is often found in high-moisture areas, including bathrooms, kitchens, and outdoor spaces. But does the use of grout in these environments make them waterproof? This article explores the different types of grout, as well as water-resistant and waterproof options, to help you choose the most effective grout for your tiling project.
What Is Tile Grout?
Tile grout is a cement- or resin-based material used to fill the spaces between wall or floor tiles. Its purpose is to help hold tiles in place, fill gaps between tiles to prevent dust and dirt from getting trapped, and provide a smooth joint for a clean, professional tiled surface. It’s a key part of a tiling system and is available in a range of water-resistant levels and colours to suit your preferences.
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Is Grout Waterproof?
Most grouts are water-resistant, but not completely waterproof. They are often made of porous materials, such as cement, that absorb moisture rather than repel it. In time, this can lead to mouldy grout and weakened tiles. However, modern tile grouts contain additives and chemicals that enhance their water and stain resistance, making them suitable for waterproofing and ideal for high-moisture environments. For fully waterproof grout, you will need to use either a resin-based grout or there are grout sealers that can help.
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The Three Types Of Grout
When it comes to grouting tiles, there are three types of grout to choose from. The best grout for you depends on your tiles, location, and tiling project.
Cement-Based Grout
The most common type of grout used for wall and floor tiles
Often available in sanded and unsanded formulas
Not waterproof!
It’s a porous material, so it may absorb water if left unsealed
Requires a grout sealer to improve water resistance
Popular ranges include: UltraTile Fix ProGrout Flexible Wall & Floor Grout and Ultra Scape Flowpoint Rapid Setting External Grout.
Epoxy Resin Grout
A waterproof grout due to its resin formula
A flexible grout, but with a hard, more robust finish
Highly water and stain-resistant
Ideal for high-moisture environments like bathrooms, kitchens & spa’s
Popular ranges include: Kerakoll Fugalite Colour Waterproof Resin Epoxy Grout and Mapei Kerapoxy Easy Design.
Water-Repellent Grout
Often a polymer-modified grout, which makes it water-repellent
Additives in the formula help resist water and staining
A good mid-range grout for kitchens and bathroom tiles
Remains a flexible and durable grout
Popular ranges include: Mapei Ultracolour Plus Fast Setting Water-Repellent Flexible Grout
View Our Range Of Water-resistant Tile Grout
We offer a wide range of high-quality grout from leading brands, including Ultra Tile, Kerakoll, Tilemaster Adhesives, Mapei, Larsen, BAL, and Ardex. Here are some of the most popular water-resistant grouts available:
Product | Image | Waterproof Level | Where To Use |
 | High water-resistance | Wall & Floor Tiles. Interior & External. Suitable for Underfloor Heating Systems. | |
 | Water & Frost-Resistant | Wall Tiles. Dry or Wet Environments. Interior & Exterior. Suitable for Swimming Pools. | |
 | Water & Mould-Resistant | Internal & External. Wall & Floor Tiles. | |
 | Water Repellent | Internal & External. Wall & Floor Tiles. Suitable for Swimming Pools. |
How To Waterproof Tile Grout
Whether you’re looking to waterproof your new or existing grout, you can do so by adding a grout sealant, which will help protect your tiles from water damage.
If you are applying grout sealant onto existing grout, we strongly recommend cleaning it, removing any mould, and repairing any cracks before sealing. If you need to remove and reapply grout, ensure you have the right tiling tools and follow our How to Remove Grout Guide.
4 Steps To Waterproof Your Tile Grout:
Select your preferred water-resistant grout, such as cement grout.
Once your tiles are installed, apply the cement grout and leave it to fully dry and cure.
Apply a grout sealer on top of the cement grout, and leave it to dry.
Finish the corners and edges with a water-resistant silicone sealant or tile trim.
How to Apply Epoxy Grout
Using the right tiling tools, follow these four steps to accurately apply and seal your epoxy grout for a complete waterproof finish.
Use an epoxy resin grout, which is already highly water-resistant and stain-resistant.
Once your tiles are installed, apply the epoxy grout and leave it to fully dry and cure.
Finish the corners and edges with a water-resistant silicone sealant or tile trim.
It’s worth using a tile cleaner every so often to maintain it’s high quality look.
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