How to Lay Waterproof Floor Tiles like a Pro
But first, we'll need some materials and tools.
Tools and equipment needed
- Tile and grout sealant
- Smooth mortar
- Waterproof membrane, like KERDI wrap
- Finishing trowel
- Utility knife
- Tile cutter
- Vacuum cleaner
- Tape measure
- Table saw
- Tile cutting blades
Step 1: Prepare the floor area
The first step is to remove any baseboards/trims in place around the perimeter of the floor in question. You will be replacing these later, but this is the best practice for making the floor as waterproof as possible.
Use a Stanley knife to cut away any sealant, and simply prize the board from the wall. It should come off relatively easily.
With that stage complete, the next is to remove any existing flooring, like vinyl sheeting. Rip up using a crowbar, or cut up into pieces, the old flooring and dispose of it appropriately.
If the structural flooring underneath is timber, make sure you hammer down and generally flatten, the surface ready for the tiles later. Things like rogue nails, or screws, should either be removed, or secured into place.
Also check for any ridged surfaces and level of/plane, as needed. For timber floors, belt sanders are a great asset. For sold floors, you might want to consider laying a self-leveling compound first.
Step 2: Add the underlayment
Next, clean the entire floor surface, and then begin to add some smooth mortar and underlayment to the floor. For the former, use a large trowel to smooth the mortar over the entire floor surface.
This is an essential step to ensure the longevity of the tiled floor once complete.
Once complete, cut to size, and lay the underlayment. Smooth out over the entire surface of the base mortar, and ensure it is well adhered to the mortar before moving on.
Ensure you waterproof/seal any seams between the underlayment too using your waterproof membrane. Also, ensure you waterproof up the wall to the height of the baseboards too.
To adhere properly, lay a thin layer of mortar, and press the waterproofing material into place.
Allow the mortar to dry fully before moving on to the next step. Leave for at least 24 hours, longer if possible.
Once the mortar is set from the previous step, thoroughly dust and clean the floor once again. This is to ensure the best possible adherence of the tiles to the floor later.
Step 3: Cut and prepare the tiles
With that complete, it is time to prepare the floor tiles. If not already done, decide on the pattern you'd like, and plan the tiling accordingly.
Measure and cut the tiles as needed. In this case, a mixture of full tile, 2/3, and 1/3 tile lengths will be used. Cut the tiles using a bench saw or a purpose-built tile cutter as needed.
Remember to factor in services that poke through the floor, and other obstructions on the floor. Tiles will need to be cut around these.
When cutting, ensure the room is well-ventilated, or wear a mask. Ideally cut outside. For any exposed services (like water supplies and waste pipe connections, etc), plan your floor and mark up the tiles accordingly.
Cut as needed.
You should also try to make the cuts a little bigger than the actual obstruction to give you some margin or error when laying. Always take into account the width of tile spacers too between the tiles.
Ensure you lubricate any cutting tools to prevent the melting of any metal components. Also, be careful not to snap the tiles too, and try to use carbide or synthetic diamond edges blades.
If you are cutting out holes, make sure all the legwork is done on the base of the tile so cut marks don't show on the decorative tile faces.
Step 4: Add the main tile mortar and set tiles
With the tiles prepared, the next stage is to prepare the floor to receive the tiles. Mix up your tile mortar according to its instructions.
When mixing, you may want to consider using warm water to make mixing and spreading easier on your hands. It also gives you a little more time before the mortar sets fully if you need to reposition tiles.
Before committing yourself, add some guide lines on the floor to ensure the tiles are squared with walls, etc.
Once complete, damp down all surfaces using water and a regular sponge. This will remove any invisible dust and debris.
Now begin to spread the mortar over the surfaces to be tiled. Again, use a flat blade trowel for this.
Ensure you leave any exposed services clear of mortar. Do in small sections, and then begin to lay the tiles as needed.
Apply a thin layer of mortar to the rear of each tile before laying. Ensure you add spacers between each tile to provide enough space for the grouting later on.
The first row is the most important, as it will guide the others, so make doubly sure it is squared up with the wall.
The tile's weight should keep it level, but always check now and again the floor surface is level using a spirit level. Use a rubber mallet to knock tiles in the base mortar if they are not quite right.
Always keep a bucket of warm water and a sponge handy to clean up any excess mortar as you go.
Pro-tip when laying tiles — always plan your floor so that any cut edges are towards the wall (and consequently under the trim/baseboard). Keep all factory edges for the main floor itself where possible.
Also ensure you leave a small gap between tiles and the walls, as tiles do move sightly as the mortar sets and the tiles settle into place.
Step 5: Grout the tile joints
With the tiles down, the next stage is to grout the joints. Mix up the grout according to their instructions, but as a general rule of thumb, you want the consistency of cookie dough.
Trowel the grout over the tile lines, and make sure you squeeze it between the tiles. You want to fill the gap completely.
Then let it sit for around a quarter of an hour, before cleaning off the excess using a sponge and water.
Like the tiles, complete the grouting in sections. Grout a set amount of the area, and then return to clean off the excess.
Always begin each swipe with a clean section of the sponge to prevent smearing. Do this in a smooth action along the grout line. Rinse the sponge completely, and repeat for the entire floor.
Once complete, allow the grout to set for at least 24 hours.
Step 6: Seal the tiles and grout
With the grout completed and cured, it is time to seal the tiles and grout. Run the sealant along each and all of the grout lines.
Some products come with special applicators to make this process super easy.
Allow the grout sealant to cure.
With that, your tiled floor is finished! Well done you. Now, you'll be needed a new project. How about an outdoor BBQ?
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