Use the right adhesives

There were times when only cement sand mortar was used as the bedding material for fixing final flooring material like marble or tiles over it. These days, many types of adhesives have been invented by the construction chemical companies. Use of these adhesives ensures high strength bonding of flooring tiles or stone with the base, thus providing better quality and workmanship. Let us have a look at some of these adhesives and their right use:

Adhesives for tile on tile flooring

Many people are desirous of changing the flooring of their already constructed houses these days. Arrival of new, attractive and trendy building materials in the market and their display in the building material exhibitions has acted like a magnet for house owners who want to renovate the floors of their houses yet wish to do it without dismantling and disposing the old ones and also by minimising the expenditure involved. Floors undergo wear and tear, lose their shine, develop stains and begin looking shabby with the passage of time. Such bad condition of floors has its effect on the overall appearance of the house. House owners often want to lay tiles over all these kinds of floors to give them a new look.

Tiles can be laid over the existing floors without dismantling them if resizing of doors is possible in the house. Whenever we plan to lay a new flooring over an existing one, the new level of the floor is likely to rise by 12 mm or even more. Even if thickness of adhesive layer is kept just as 4 mm, fixing of 8 mm thick tiles over it will demand 12 mm rise in floor level. This requires resizing of door shutters in the house which need to be shortened in their depth by 10 to 12 mm. if this is possible then tile flooring over existing floors can be laid.

For fixing tiles over existing floors, non-skid type adhesives should be used. These adhesives are prepared by using special blended polymer modified cement. These are supplied in powder form of grey colour and need to be mixed with water to prepare the paste. These should be checked to have low shrinkage properties and able to accommodate thermal movements. These adhesives are supplied in smaller packages also of 5 kg, 20 kg, 30 kg and so on. These tile on tile adhesives can be used for fixing vitrified tiles or ceramic tiles on the floors, irrespective of material of tiles. Better strength of these adhesives enables their use both in indoor and outdoor work.

A 30 kg bag of this type of adhesives cost around Rs. 700. These adhesives thus cost almost double the price of cement.

Adhesives for wall cladding

Provision of vitrified tiles, ceramic tiles or stone tiles on front elevation or walls of a house has become very common. For such an application, special adhesives of blended polymer modified cement, designed for heavy duty applications are now available. While buying adhesives, the purpose of their use should be made clear to the stockist. These adhesives are ready to use type and are mixed with water to prepare the mixture to be applied on the walls and the back of the tiles during cladding work. These adhesives are also in grey powder form and supplied in 25 kg bags. These adhesives are quite costlier and cost about Rs. 850 to Rs. 900 per 25 kg bag.  

Adhesives for fixing tiles & stones on wood or plywood

Special adhesives used for fixing tiles and stone tiles on plywood have become available in the market now. These types of adhesives are supplied in 5 kg packs and are in liquid form that is white in colour. Generally this type of adhesive is mixed with non-skid type adhesive for use. It develops high bond strength and can be used even in vibration prone areas. Its high bond strength permits its use over wood or plywood surfaces.

Adhesives for fixing PVC tiles

PVC tiles are the easiest to lay and provide a beautiful look. These also demand minimum reduction in size of door shutters as thickness of PVC tiles is hardly 1.5 mm to 4 mm. For houses, just 1.5 mm thick tiles prove sufficient. Many reputed companies produce PVC tiles that give a very smooth and beautiful look and resist stains and scratches also. Laying them is also easier than other types of tiles. For fixing PVC tiles, rubber adhesives are used. Fevicol SR 998 and Dunlop S 758 are some of the really good adhesives. 

Right method of using adhesives

It is vital to create proper bond between the existing floor and the new flooring material whenever decision is taken to lay new flooring over the existing one. For this purpose, the right choice and application of adhesives plays a crucial role. While the right adhesives should be chosen as described above, their way of use is also important. For right application, apply the adhesive both on the base as well as the back of the tiles with a notched trowel to give a good grip to the tiles. In most cases, adhesive is applied by the flooring man on either of the two surfaces. Apply the adhesive both on both surfaces and take care after its application that the adhesive feels sticky to fingers but does not come off. This is the time to fix the tile on the floor or the wall.

Adhesives for flooring tiles

Whenever a new floor is to be laid, adhesives produced for use in new construction work should be chosen. These adhesives are polymer-modified cement-based products that provide excellent adhesion to the base material. These adhesives are supplied in powder form and are required to be mixed with water for installation of tiles. Packing is done in 25 to 30 kg bags. While choosing these new construction adhesives, it should be checked that these are water resistant, have zero or low shrinkage property and are able to bear thermal movements. These properties help in avoiding cracking of tiles fixed in the floor. These adhesives are in grey colour powder form. The thickness of adhesive layers below the tiles should be 3 mm to 6 mm. For 6 mm thickness of adhesive layer, one 30 kg bag should be sufficient to provide 30 to 35 square feet of floor area. Thus for a 200 square feet room, about 6 bags of new construction adhesive shall be required.

A 30 kg bag of these types of New Construction Adhesives should cost around Rs 500. Therefore, though costlier than cement which costs about Rs 300 for 50 kg bag, these adhesives are worth their price.

Adhesives for tiles on walls

For fixing tiles on walls, same non-skid adhesive that is used for tile on tile flooring work, can be used. Both vitrified and ceramic tiles can be fixed on walls by use of this adhesive. However, care should be taken that total height of tiled portion of wall above floor level doesn't exceed 10 feet.

Adhesives for fixing glass tiles & mosaic

Special high strength adhesives are now available for fixing glass tiles and glass mosaic on internal and external surfaces of walls or floors. These adhesives are also suitable for fixing tiles on walls of swimming pools. These adhesives are white in colour and are available in 5 kg and 25 kg packing. These adhesives are also suitable for fixing marble slabs on walls and floors. Floors prepared by use of these adhesives are ready for use after 24 hours. While fixing marble, a thickness of 6 mm of adhesive has to be laid for proper bonding and strength. In case of glass tiles, a thickness of 3 mm of adhesive is sufficient. However for fixing glass mosaic, an adhesive thickness of just 1.5 mm can be sufficient and thus an area of about 90 to 100 sq ft can be covered by using just one bag of this adhesive. A 25 kg bag of this type of adhesive costs about Rs 1300. Thus, this type of white adhesive is much costlier than all other types of adhesives.

— The Author is HOD and Engineer-in-Chief, Civil Design and Construction in a Punjab PSU.