Check the substrate

Before tiling an area, it is important to understand that your substrate, usually the screed, is in good condition. The grout and tiles can only perform as well as the substrate to which they need to adhere. The screed should be no less than 10mm thick. If it is less than this, it is more fragile and can crack easily. If the screed is not solid enough or has a sandy finish, you need to address these problems before you commence tiling. When a screed is laid, it is necessary to make provision for floor movement. If no joints have been provided for movement, the screed will crack and subsequently crack the tiles. 

 

Tip!

Don’t forget to waterproof

Before you lay tiles, consider whether the area to be tiled needs to be waterproofed, for example walls and floors of showers, balconies and around water features. Use a suitable waterproofing product to waterproof the substrate prior to tiling. The adhesive and grout in these areas should also be mixed with a latex-based additive that, when used in place of water in the mix, improves the bond strength, flexibility and water resistance of cementitious adhesives and grouts. 

 

How to tile your floor                            

Choosing the correct tile adhesive is important. See the article on page 18 for more information.

 

Step 1: The right start will ensure a proper job. Mark the centre point of the room and transfer these marks to the corresponding walls.

 

Step 2: Starting at the centre mark, place a row of loose tiles along these lines. Cut tiles should be at least half a tile wide. Position straight edges as per step 3 below. Remember to leave room for tile spacers and tile panel movement joints and perimeter joints.

 

Step 3: If cut tiles are too small, move the centre tile so that the middle of the tile aligns with the mark on the floor. Repositioning the tiles will now ensure correct cuts. Mark the new starting point and transfer these marks to the corresponding walls. Position straight edges on these marks in both directions.

 

Step 4: Start at the centre of the room. Use appropriate adhesive for the tile and traffic conditions. With the straight edge of a trowel, spread the adhesive onto the floor.

Tip from TAL: All exterior or exposed and wet applications as well as areas subjected to moisture, movement (like suspended slabs) and thermal stress require the water in the adhesive mix to be replaced with TAL Bond, a latex additive that improves the water resistance, flexibility and bond strength of the adhesive.

 

Step 5: In a horizontal direction, notch the adhesive with the trowel. Do not spread more adhesive than can be tiled in approximately 15 minutes to prevent the adhesive from ‘skinning’ before the tiles are installed.

 

Step 6: Use dry tiles and ensure that the backs of tiles are clean and free from dust and contaminants. Bed the tiles firmly into the adhesive using a rubber mallet.

 

Step 7: Never butt-joint tiles. Use spacers to create uniform spacing. Remove them before applying grout.

 

Step 8: Lift the occasional tile to check for full coverage of adhesive on the back of the tile. No voids should occur underneath the tiles.

 

Step 9: Tile out from the centre mark to the edges, keep lines straight and tile spacing even. Leave cut tiles until last.

 

Step 10: Measure and cut each tile to fill edges leaving room for the spacers. Butter the back of the tile with adhesive, place cut edge towards the wall and bed firmly into place using a mallet.

 

Step 11: Allow adhesive to dry before applying grout (refer to the adhesive packaging for drying times). Be sure to follow the instructions on the grout packaging for the correct mix ratio. Work grout well into joints with a grout squeegee, ensuring that the joints are properly filled and that the grout is compacted into the joints.

 

Step 12: Remove the excess grout with a damp (not wet) grouting sponge. Allow the grout to dry and then polish with a dry cloth.

 

Step 13: Provide movement joints in all corners and in large tiled areas approximately 5m apart internally and 3m apart externally. Rake out joints and leave ungrouted. Fill with a flexible joint sealant.

 

Sources:

Information and images supplied courtesy of TAL.

Contact the TAL Technical Advisory Service on 0860 000 (TAL) 825 for more information on tiling and tiling products.