A lot of myths exist about laying floor tiles onto wood. The truth is that if you follow some simple rules it's not only possible, but no more difficult than any other substrate. In fact, your prepared floor is often more likely to be flat than a concrete floor. So go ahead and choose your floor tiles safe in the knowledge that you can safely and easily tile a wooden floor
So what are my options when tiling a wooden floor?
Existing wooden floors are often either floorboards or chipboard; neither of the best surfaces for tiling onto directly. The problem with tiling onto floorboards is that they can move and flex when walked on, and this causes cracks and tile lifting. Tiling onto chipboard floor is inadvisable too as it reacts badly to moisture often expanding and flaking. Newer moisture resistant chipboard (often green) is treated and has a shiny surface and isnt ideal. You can sometimes tile directly onto these surfaces see this related blog post tiling onto a chipboard floor
Preparing the wooden floor for floor tiles - this applies to all methods:
- Screw down any loose\moving floorboards (mind out for pipes and electric cables!). You can work out where the joists are quite easily, they will run in the opposite direction to the floorboards. If you look closely you will see a line of nails in the floorboards. Just follow these - draw a line on them if it helps. Excess movement must be stopped before proceeding so have a good stamp around.
- Sweep the area clean.
Method 1 - Use a tile backer board. This is our preferred method.
This method is ideal as the tile backer board is quite thin (6mm), reducing the step created. It's by far the easiest method. The tile backer boards reduce noise, are waterproof and are sized to be easy to handle.
- Using a silicon gun, run 2 small beads of instant grab adhesive around the back of a single tile backer board. One bead around the outside, and one further in toward the middle in a square shape.
- Lay the board down, starting in a corner of the room. a few small gaps around the board don't matter too much. Press\tap down firmly so that the adhesive 'grabs'.
- Drill 8 holes in the backer board using a masonry drill bit. Do not drill into the floorboard behind.
- Screw the through board into the floorboards\chipboard using a cordless driver. Use 25mm 8-10 corrosion resistant screws as these will not protrude through the floorboard so no danger of damaged pipes! Ensure the screw heads are flush with the board (you may need to countersink the holes)
- When you are ready to lay the next board, run a small bead of adhesive along the edge of the previous board so that the two are bonded together. Stagger the joints of the boards as you lay them so they are in a brick pattern.
- You can cut the boards using a backer board cutting tool, simply score and snap the board. For shaped use a jigsaw.
- Repeat until done!
- Prime the boards using an SBR primer, one part SBR to 3 parts water - do NOT use PVA.
- Fix your tiles using a single part flexible adhesive and grout with flexible grout.
Here at Trade Price Tiles we stock No More Ply. A very useful extra guide can be found on the manufacturer's site.
What you may need for the job
Method 2 - Overboard with plywood sheet.
This is the traditional method and over the years served the trade well. Due to the need to use 12mm WBP\Marine plywood this can create quite a step. Ply has also become incredibly expensive these days. Put simply, it's now the second best method.
- Cut and shape the ply using a jigsaw or saw. Try not to cut the sheet down unless you absolutely have to - you don't want joints all over the place.
- As in the previous method use your favourite grab adhesive on the back of the plywood and lay it down on the floor.
- Screw the ply down using a cordless driver; ensure screw heads are flush with the board. Screw using a grid pattern with a corrosion resistant screw every 250mm minimum. With this method you must make sure that you screw to the joists as well as the floorboards. Be careful not to damage pipes or electrical cables.
- Prime the ply using an SBR primer or Acrylic Primer one part SBR to 3 parts water - do NOT use PVA.
- Fix your tiles using a 2 part flexible adhesive (adhesive powder and 'milk') and grout with flexible grout. 2 part adhesive is required when tiling onto ply floors.
You will usually have to use a tapered threshold board to make up the difference between the two floors.
Some sites state that tile backer board is more expensive than ply; however they miss the bigger picture. Ply is harder to fit, you are more likely to damage your services due to the need to screw into the joists, and the requirement to use a 2 part adhesive mean that ply is always more expensive to use.
Other methods for tiling a wooden floor
Some sites propose removing the existing boards and laying 25mm WBP plywood. You can do this if you choose but it's a hell of a job, andunnecessary. You will still have a slight step due to the tiles and you will still have to use a 2 part flexible adhesive. Save your time and cash.
Other matting type products are also available such as Ditra matting by schluter systems. These are really designed to prevent problems caused by lateral movement such as at the join of two different surfaces.