For bonding carpet tiles backed with PVC, polypropylene and bitumen with fibre backing.
Suitable for bonding to raised access floor panels, concrete, cementitious screeds, asphalt, terazzo, chipboard, hardboard, plywood, smoothing compounds and existing floor coverings, e.g. thermoplastic tiles, PVC or linoleum.
Suitable for use where there are underfloor heating installations, (surface floor temperature must not exceed 27°C). However heating should be switched off at least 48 hours before and after the installation of floor covering.
Physical:
- Water borne
- Non flammable
- Approx. specific gravity : 1.00
- Application temperature limits : +5 to +40°C
- Service temperature limits : up to +40°C
Consumption:
90-120 m² per 15 L depending on porosity of subfloor and tile backing
Shelf life:
12 months under good storage conditions in original, unopened containers. Keep out of direct sunlight, at a temperature of between +5°C and +40°C. PROTECT FROM FROST.
All phases of the installation should comply with the latest edition of the following standards :
- BS CP102 Code of Pratice for protection of building against water from the ground.
- BS 5325 Code of Practice for the installation of textile floor coverings.
- BS 8203 Code of Practice for installation of resilient floor coverings.
Subfloor : Ensure the subfloor is clean, sound, dry and free from contaminants that may hinder adhesion, including surface hardeners and additives.It should also have an effective damp-proof membrane. The subfloor should be tested in accordance with British Standards, using a properly calibrated and insulated hygrometer. A reading of 75% RH or less confirms that the subfloor is satisfactorily dry. Where this has not been attained, it is necessary to apply a ScreedMaster surface membrane to suppress residual moisture. For further information contact Bostik Technical Service.
Smoothing compounds: Mechanically remove any surface treatments on concrete bases. Repair any deep indentations in the subfloor with a rapid repair mortar (Plycorapid). When floor requires smoothing, apply a suitable ScreedMaster smoothing compound at a minimum thickness of 3mm. ScreedMaster 2 is suitable for areas of normal or high intensity foot traffic. ScreedMaster 1 is necessary for areas subjected th heavy loads.
Existing floor coverings: Laybond L79 is suitable for use over existing PVC and linoleum. Ensure all traces of polish and contaminants have been removed.
Priming: Surfaces should be thoroughly cleaned (preferably vacuumed). Prime boards and other porous surfaces with Gripfill PVA (diluted 1:5 with clean water) or Universal Primer and allow to dry. This is particularly important with hardboard, chipboard and plywood. Ensure that the floor covering manufacturer recommends the floor covering for use with the particular substrate.
APPLICATION
In order to achieve an overall release bond, Laybond L79 should be applied by soft brush, short haired lambswool (or mohair) roller or trowel over the entire floor area and allowed to dry to a clear, transparent tacky film. Once clear, the tiles should be laid into position, ensuring that no air is trapped. Alternatively, adhesive can be applied to the back of the tiles and left to dry to a clear, tacky film prior to bonding. NB On porous surfaces a permanent bond can be achieved by laying into wet adhesive. However, by doing so onto non-porous surfaces (especially metal) will result in moisture entrapment and possible rusting of the metal access panels.
DRYING TIME
This will depend on ambient temperatures, humidity and air flow. WIth low humidity and good air flow the drying time at 15°C should be 30-45 minutes. However if conditions are cold and/or wet, it may be markedly longer (i.e. overnight). It is essential to ensure complete drying of the adhesive prior to laying the carpet tiles, particularly on metal surfaces. Note : Fuel burning space heaters produce water vapour which will increase humidity and extended drying time. Electric fans, where permissible are more effective.
