Before any work starts, lay out protective sheets to cover surfaces and minimize dust levels.
When it comes to re-tiling, doing it tile on tile is a standard process (especially on Malta and Gozo)
Before re-tiling starts, the surface needs to be checked for the following:
Tiles are in good condition and evenly placed with no cracks in them, loose or missing tiles. If this is the case, then the surface needs to be fixed. Any loose tiles will have to be attached and if any of the old tiles are damaged or chipped, then they must be repaired. Repairing the old tiles and ensuring they are set correctly will create a solid base for the new layer of tiles.
Check for mould and any discolouration in the grout which can highlight an issue with water infiltration or humidity. If this is the case, we recommend that the old tiles are removed fully and the water infiltration or humidity issue is treated, before applying your new tiles from scratch.
Once each tile is secured and there are no chips, the surface needs to be levelled out with either sandpaper or an electrical sanding machine. The surface of the tiles should now feel roughened. Any smooth surfaces on the old tiles need to be scuffed out with sandpaper to create an abrasive surface, creating better adhesion and ensuring that the next layer of tiles grip well.
The surface to be re-tiled must now be completely sound and clean, dry and totally dust free. Any surface contaminants such as grease, oil and efflorescence must be removed, in order to promote a ready surface that promotes adhesion.
RALASTOCEM which is a specially formulated latex and resin- based tile adhesive additive, which in the case of the tile on tiles method is a MUST. Adding Ralastocem makes the adhesive (tile glue) considerably more flexible, strong with more elasticity and improves adhesion and any possible deformities. Ralastocem is to be diluted with clean water on a 1:3 ratio and added to the powder adhesive, in this case Rabond Flex Plus (C2TE White or Grey). If a glue such as Rabond Flex (C2T White or Grey) is to be used, then the Ralastocem dilution is to be 1:1.
RABOND FLEX PLUS (White/Grey) should be mixed with a mechanical paddle mixer on a low- speed setting to achieve a smooth and lump free consistency. Mix in a clean bucket using approximately 7-8 litres of liquid (Ralastocem and Water 1:3) per 25Kg bag. Allow the mixture to stand for 5-6 minutes and then re-mix thoroughly before application. Use a notched trowel to apply the adhesive (we recommend 10 mm teeth). Curing time is 3 days and it is important not to put any pressure or walk on the tiles during the curing process.
Apply a layer of adhesive on top of the old tiles as well as the tile itself. Then, comb the adhesive in one direction, this will enable better cohesion.
Once you have evenly applied the adhesive, lay your new tiles. Make sure that each tile is properly aligned before you set it down and slide it into place. Then as you add new tiles, use the self-levelling tile spacers to ensure even spacing between each tile. Tile spacers come in various sizes – 1,2,3 and 4 mm spacers are available from R A & Sons. When you are certain that the tile is in the correct position, press firmly on it to set it in place. Use tiling wedges to level and secure the tiles in place.
Once the Adhesive is fully set, the tiles are ready to be grouted.
RAGROUT powder is to be mixed with 30-35% water by weight in a clean container. Mix mechanically until a homogenous lump free mixture is achieved. Let the grout stand for 5 minutes and mix again thoroughly. Even though Ragrout is waterproof when used in swimming pools, wet rooms or areas that experience heavy foot traffic combined with sudden changes in temperature, mix Ragrout with Ralastocem to improve elasticity and impermeability
For joints from 6-15mm add 1.2kg of calcium carbonate 300 micro to 5 kg of Ragrout. Always apply Ragrout with a rubber grouting tool. When removing excess still fresh grout use a damp sponge or cloth and never wet areas excessively. Floors can take foot traffic after 24 hours and he grout will be fully cured after 5-7 days
Fill the joints with Ragrout using an appropriate rubber trowel without leaving any gaps. When the residue paste is being removed, use a damp and highly porous sponge, making sure to rinse the sponge frequently so as to leave the cleanest possible area in contact with the surface. This will ease the necessary cleaning when the joints are dry and might possibly result in not having to use any specialised products for the cleaning of the joints.
RAGROUT comes in a variety of colours. Please ask the R. A & Sons team for the grout colour chart and for any further assistance.
SAFETY NOTE: Wear the right shoes and the proper clothing. Use gloves, eye goggles and ear protection when necessary. It is important to take extra care when you are working on any sort of wet surface.