Preparing bathroom walls for boarding and tiling

Before you do anything at this stage, you must ensure that you have already completed any pipework that’s necessary. (You’ve probably heard horror stories of those who didn’t…)

Remember too, that you can’t tile over glossed surfaces, lead paint, plywood or wallpaper. If your client has lead paint on the walls, this must be removed carefully, to prevent the dispersal of toxins. It’s worth a reminder: always wear safety goggles, a face mask and plastic shoe covers to avoid spreading the poisonous dust.

Time-saving tip: Before you start on the walls, you might want to paint the ceiling, as you will not splatter the bath or any tiles with your paint roller – you also don’t have to carefully cut in at the edges as you would if you carried out this process after tiling the walls

  • 1. Prepping the walls for tiling

    If your client has asked you to retile or add tiles to their bathroom wall, then you have to prep the wall surface. First, carry out your usual assessments to ensure that the wall is both solid and structurally sound. It should be firmly attached to the wall studs – no flexibility at all.

    As ever, check that the tiling surface is both dry and smooth.

    Next, cover the surrounding surfaces with whichever method you normally use. Most go for plastic dust covers and masking tape.

    Remove anything that is fixed to the wall you’re going to tile, such as light switch plates, electrical outlet boxes and any ceiling moulding.

    Prepping drywall

    The first step is to seal the wall with a drywall compound and leave to dry, before sanding it with medium-grade sandpaper. Don’t leave the surface too smooth, so the tile adhesive can get a good grip on the wall.

    To get rid of any residual dust, give the whole wall a once-over with a damp cloth then leave to dry again.

    Prepping a painted drywall

    Scrape off any residual paint and lumps or bumps. If you need to, now’s the time to fill in any large cracks with filler. Sand over to smooth out the wall surface – a medium-grade sandpaper should do it. Then leave to dry ready for tiling.

    Prepping a plasterboard wall

    Avoid future problems by ensuring that you’ve filled in any cracks or holes. Use some filler then sand it over until it’s smooth. Prime the wall, then use water-resistant tile adhesive to affix the tiles.

  • 2. Installing Tile Backer Board

    Here’s a reminder of how to install tile backer board dependent on the type of wall you will be installing it to…

    Stud Wall Installation

    HardieBacker® 12mm is recommended for wall application for thickness transition with other products.
    1. Ensure framing is structurally sound
    • Must comply with local building regulations.
    • Max stud centres = 400mm. Ensure that all corners are adequately blocked with suitable timber.
    • All existing old dry lining should be removed as it has potential to fail further.

    2. Determine layout of boards
    • Boards may be installed vertically or horizontally.
    • Ensure all vertical joints are made on the centre of the studs.
    • Score-and-snap boards to required sizes and make necessary cut-outs.

    3. Install boards 12mm to framing
    • See applicable building regulations regarding vapour barrier requirements.
    • Use HardieBacker® screws or 30mm galvanised roofing nails when using timber studs.
    • Install boards 6mm above the floor, bath, and shower tray. These floor and wall joints should be filled with a 6mm bead of high quality wet area sealant.
    • Keep fixings 15mm from board edges and 50mm in from sheet corners.
    • Set heads of fixings flush with the surface, without overdriving.

    4. Tape joints prior to tiling
    • Prior to setting the tiles, embed 50mm alkaline resistant Fibatape across joints and feather tile adhesive to leave a 150mm wide joint.

    man cutting hardiebacker

    Masonry Wall Installation

    HardieBacker® 6mm can be used on top of masonry walls
    1. Ensure wall is sound, clean and dry and ready to receive tile backer board.
    • The rear of the board must be wiped down to remove dust.
    • All existing old dry lining should be removed as it has the potential to fail further.

    2. Use a high strength gap filling adhesive
    • Place 3 vertical 10-12mm beads of high strength, single part, gap filling cartridge adhesive, evenly down the back of the board.
    • Press board firmly against the wall into the desired position.

    3. Fasten HardieBacker® 6mm with masonry anchors
    • Fasten board with 9 (6mm x 60mm) stainless steel screws into brown wall plugs. Screws should remain 100mm from the top and bottom edges and 50mm from the left and right edges. Ensure min 50mm embedment into the wall.
    • Do not overdrive the screw; it must be flush with the face of the board.

    4. Tape joints prior to tiling
    • Prior to setting the tiles, embed 50mm alkaline resistant Fibatape across joints and feather tile adhesive to leave a 150mm wide joint.


  • What’s the best way to install tile backer board?

    This very much depends on the type of wall you’re working with, but choosing the right backer is the first step. HardieBacker® 12mm is recommended for use with stud walls, while HardieBacker® 6mm is a good choice for masonry walls.

  • How do I tile a bathroom wall?

    The process will differ depending on the renovation project. Generally, these steps will be involved.

    • Mark out your tile height
    • Install the waterproofing
    • Trim tiles to size
    • Affix the tiles
    • Apply the grout

    Find out more about each step >>>

    Our supplier EVO-STIK have done a helpful video you can watch too…