Tiling in a damp fireplace
I am looking to tile my fireplace (just inside the recess) with split-face slate tiles. There is a little bit of damp at the bottom of the fireplace, which I have been told is not rising damp, it's just pooling. My house is 100 years old and is quite damp in a lot of places. Would it be a good idea to create a cavity between the tiles and the wall by using wood batons and a backer board, then putting a border around the front to cover the recess or would it be better to put a backer board straight onto the plaster, or just add the tiles directly to the plaster without boarding?
Advice from 7 local tradespeople
I sugest to use backer board straight on the wall
don’t batten it out with wood.
Because you already have damp:
Wood battens can trap moisture ? risk of rot and mould
Creating a cavity there can actually make damp worse, not better
Best option:
Fix a cement backer board directly to the wall (or use tile adhesive if the surface is sound)
Then tile onto that
Even simpler (if the plaster is solid and not crumbling):
You can tile directly onto the plaster
Key point:
Keep it breathable and avoid trapping moisture behind the tiles.
Personally, i would be stripping it back to brick, then give it a few days to air out and dry of. All being well I'd fit a concrete back board or something similar. This gives extra protection for the damp brick. Also it's a good level surface for the tiles to go on to
Do not use wood battens in a damp fireplace, as they can absorb moisture and rot. It’s better to fix a cement tile backer board directly to the wall and tile onto that after treating the damp area as much as possible.
Given the age of your home and the specific issue of "pooling" damp, your choice of installation method is critical. If you trap moisture behind a non-breathable surface like slate, it will eventually force its way out—either by blowing the tiles off the wall or by pushing the damp further into the masonry.
In this situation, I wouldn’t recommend tiling directly onto plaster, especially with existing damp, as it can lead to failure of adhesive over time.
Best practice would be to first address the source of moisture as much as possible. For the tiling, I would install a cement-based tile backer board (such as HardieBacker) rather than standard plasterboard.
If there is ongoing damp, creating a small cavity using treated timber battens and fixing a backer board on top can help with airflow and reduce moisture build-up behind the tiles. All materials used should be suitable for damp environments, including flexible adhesive and grout.
Overall, a solid, moisture-resistant backing with proper preparation will ensure a long-lasting and professional finish.
Screw cement backer board to the wall
Use tile adhesive
Add your split slate tiles
