How to tile onto bitumen

Bituminous paint is commonly found on floors in properties, used as a damp-proof membrane or where parquet flooring has been used. Bitumen has a wide variety of uses as it provides an effective waterproof, weatherproof, chemical and corrosion resistant protective coating.

It is made of bitumen or coal tar which is dissolved in mineral spirit or naphtha. Bitumen is also known as asphalt which is sticky, black, and highly viscous liquid or semi-solid form of petroleum.

Almost all products such as levellers and adhesives come away from the surface when there is Bitumen present, which then causes the tiles to lift or crack. However, there are now products which do work and prevent you having to scrape off the black substance by hand.

Substrates must comply with BS 5385, parts 1-5, be stable and non-deformable, without cracks and have already completed the curing period for hygrometric shrinkage; must be free from dust, oil and grease, free from any rising damp, with no loose or flaky material.

Firstly, check it is flooring grade bitumen and has been down long enough. If so, then there should be no issues following this option. If unsure, please contact the Kerakoll Worldwide Global Service on 01527 578000 or via [email protected].

The next step is to prime the floor using the Kerakoll Keragrip Eco Primer. Shake the can well before opening. Immediately ready for use, pour the Keragrip Eco from the can onto the substrate to be covered. Apply a fine, uniform film, preferably using a sponge or synthetic fibre roller and working in the same direction. Apply a second coat crisscrossing the direction of the first.

The colouring allows the user to check whether the application is complete and uniform. Avoid any build-up of product. Once hardened, Keragrip Eco will withstand light foot traffic. Any traces of dirt must be removed using a suitable vacuum cleaner. Ensure to wash tools, sponge rollers or brushes with water before the product hardens.

The maximum period allowed for tiling is 24 hours. Once this period has elapsed, a new, complete application of Keragrip Eco will have to be carried out directly over the existing application.

Simply sweep solid level floors and lay BAL Flexbone 2Easy. This is a unique floating loose lay uncoupling mat requiring simple preparation, there is no primer or adhesive needed.

You can tile immediately on to contaminated, stained or cracked screeds and over bitumen.

Ceramic tiles should be a minimum of: 200mm x 200mm x 10mm

Porcelain tiles should be a minimum of: 200mm x 200mm x 8mm

Natural Stone should be a minimum of: 200mm x 200mm x 15mm

Roll out the BAL Flexbone 2Easy with the blue mesh side up. Roll out from the corner and cut precisely to the required length and sizes as required for the floor. Trim off any excess around up-stands using scissors or a utility knife.

Leave a 6mm movement joint around the perimeter and butt joint the edges of the BAL Flexbone 2Easy, the overlapping blue mesh covers the joints between the roll lengths. BAL Flexbone 2Easy is to be laid with all necessary expansion joints in place. To ensure freedom of movement of the subsequent covering structure, tape all the movement joints using the Flexbone Joint Tape to protect against the entry of the wet adhesive bedding material through the joints onto the existing floor during the installation.

You cannot use BAL Flexbone 2Easy in wet areas approximately 1mm per day up to 40mm in ideal drying conditions (i.e. an air temperature of 20°C with a relative humidity no greater than 65%).

Drying times will significantly increase for thicker screeds or those in poor drying conditions. If you do not have a screed moisture meter, many adhesive or screed manufacturers offer a free moisture testing service.

The speed of drying out of the screed can be improved by a) increasing the ventilation in the room b) the application of external heat i.e. space heaters, combined with the use of industrial dehumidifiers in order to remove water vapour as the higher temperature encourages the natural evaporation of excess moisture.

The general rule is to work from the centre outwards so the main aim is to make sure the centre of the floor is positioned correctly. From there you can extend the tiling pattern towards the edges of the room. Measure the opposing walls, mark the centre of each and draw a line using chalk or pencil between the two points. Repeat for the other two walls and you will have found your centre point of the room. Bear in mind that rooms aren’t always perfect squares so start as centrally as you can.

From the centre of your room, dry lay a row of tiles in the 4 directions up to the walls. Make sure you include (a minimum of) 2mm tile spacer so that the joints are even. If there is only a thin piece of tile left at a wall, move your centre tile around slightly until there’s a gap of roughly the size of half a tile around the edge of the whole room. Once you are happy, mark the centre tile with chalk or pencil.

Make sure you plan ahead so you are able to exit the room without stepping on any tiles as they won’t have set. If the room is essential, you can tile half of the room at a time, so you are still able to access the room.

Always ensure the correct BAL adhesives and BAL grouts are selected for the installation.

Mix the recommended tile adhesive in a mixing bucket as per the instructions on the bag.

If you have prepared your floor using option 1 then we recommend using the Kerakoll Biogel Revolution adhesive. You must tile within 24 hours of using the Kerakoll Keragrip Eco Primer.

If option 2 was chosen, we recommend you use the BAL Rapid Flex Fibre of BAL Flex Fibre When using a large format trowel, ensure the final bed thickness of the tile adhesive does not exceed 5mm over the BAL Flexbone 2Easy. This can be resolved by using no bigger than a 12mm trowel.

Working off your set out lines and/or from a straight edge, spread the adhesive on the floor, the floor spreading evenly, ensuring the notches are in the same direction. Only cover a small area at a time, approx. 1m², as the adhesive will dry on the surface.

Place the tile on the bed of adhesive, press down with a twist and slide into place to ensure the adhesive sticks properly (for larger tiles, it may require a thin layer of adhesive on the back of the tile as well as the floor).

Put the spirit level or your straightedge on the tile in both directions to ensure it is even and flat then insert a tile spacer in between each tile. Be sure to press the spacers well below the surface of the tile so that they’ll be hidden once your floor is grouted. Remove any adhesive from the tile face with a damp sponge as you go along as it’s much harder to remove once set.