A comprehensive guide to backer boards

Backer boards are prefabricated sheets that are often attached to walls and floors to form a sturdy base onto which tiles can be laid. They have a perfectly level surface to tile onto, allowing for more weight (up to 200kg per m2) than a regular plastered wall.

Backer boards serve as a stable and moisture-resistant surface to support and protect tiles from damage and moisture-related issues. As a result, they are commonly used in wet areas like bathrooms, kitchens, and showers, as well as for exterior applications.

Tile backer boards are available in a range of sizes (4-50mm thick), some boards also have insulation and soundproofing properties.

Cement backer board, the most commonly used type of backer board, is made from a mixture of cement, sand, and reinforced with fibreglass.

Cement backer board is waterproof, making it an ideal choice when it comes to tiling areas that are directly exposed to water such as showers, bathrooms, and wet rooms.

When it comes to cutting cement backer boards, one of the simplest techniques involves scoring the board’s surface with a score-and-snap knife and then snapping it along the scored line. Alternatively, power tools can be used to cut this type of tile backer board.

Fibre cement backer board is typically made from a mixture of cement, sand, and cellulose fibres. This combination of materials gives fibre cement backer board its strength, durability, and resistance to moisture.

As this tile backer board is water-resistant and resistant to rotting it means that it is best suited for areas that are prone to water exposure, such as wet rooms or bathrooms.

Popular brands of fibre cement backer board include: Hardiebacker.

Glass mat gypsum board is a multi-purpose board that can be used in a range of applications. It is made from water-resistant gypsum, treated with silicone, and reinforced with fibreglass mats on both sides of the gypsum core.

Glass mat gypsum board is more resistant to moisture compared to traditional paper-faced drywall. It is often used in areas with high humidity or moisture, such as in bathrooms and kitchens.

Water-resistant drywall board is a type of gypsum board that is used for walls that may be exposed to moisture, but that do not come in direct contact with it.

This type of board is moisture resistant, however, it is not suitable for wet areas as it can easily be damaged by water. For this reason, it is commonly used on walls and ceilings in areas with increased moisture and humidity levels such as bathrooms, kitchens, and basements.

Foam-based tile backer boards are typically made from either polystyrene or polyurethane foam, making these boards notably lighter than their cement-based counterparts. The foam is then covered with a layer of cement which not only enhances the strength of this backer board but also ensures that it is moisture resistant.

As foam backer board is moisture resistant, it means that it can be installed in a range of spaces, such as in wet rooms, shower rooms, and bathrooms.

Popular brands of foam-based tile backer board include: wedi.

You can use backer boards for:

Problematic surfaces with excess flex and movement – using a backer board gives better strength and structure to reduce the amount of flexibility. For example, on floorboards.

Wet rooms – Some backer boards like XPS boards are waterproof making them perfect for tiling in a wet room, they prevent moisture damage and mould growth.

Underfloor heating – Some tile backer boards offer great insulation properties, making them perfect for use with underfloor heating to prevent loss of heat and increased energy expenses.

Size vs suitable use:

4mm - Walls only

6mm - Floors, masonry walls and plaster walls

12mm - Floors, masonry walls and plaster walls

12mm+ - Uneven brickwork and fire surrounds (see manufacturer's guidelines for suitability).