Site Conditions - acclimatisation

Installation of materials should take place in conditions as close as possible to those of the building when it is occupied.

A general room temperature between 18°C and 27°C should be maintained 48 hours prior to, during, and 24 hours after installation and a sub-floor temperature of at least 15°C is required. Ambient Relative Humidity should be between 40% and 60% RH.

2-metre rolls should be stored on site, upright, for at least 24 hours in the installation area and for 48 hours if transport or other storage is likely to have been at temperatures lower than 10°C.

Check that only one batch is being used. Wherever possible cut to length on the day before installation

Sub-floor preparation

Sub-floors must be smooth, dry, level and free from any cracks or surface protrusions, in accordance with BS8203. Excessively dusty surfaces should be primed before spreading adhesives, and other surface contaminants or materials should be removed.

Moisture testing should be carried out using a hygrometer and readings should not exceed 75% R.H.

A minimum of 3mm levelling compound should be used to smooth cementitious bases, and wooden floors should be overlaid with minimum 6mm thick plywood.

Underfloor heating should be switched off 48 hours prior to, and 48 hours after, installation. Peak temperatures of 27°C should be reached gradually over approximately 7 days.

Installation

Both factory edges should be trimmed back to ensure a sound, straight, even cut seam. With wood strip effects, care should be taken to ensure that the seam always runs along the edge of a plank pattern and the adjusted roll pattern matched accordingly. Material should be fully bonded throughout, using emulsion adhesives, laid in accordance with the adhesive manufacturer’s recommended open times, and using a correctly notched trowel.

The floor should then be rolled in both directions, using a 68kg roller to ensure good transfer of the adhesive to the material backing.

Joints should be welded once the adhesive has cured, in accordance with the adhesive manufacturer’s guidelines. For thermal welding the seam should be grooved out to a depth of 2/3 the material thickness and a width of 3.5mm. Use a speed welding nozzle of 5mm diameter and, to avoid shiny patches on the material edges, use a nozzle with a narrow air outlet. Working temperature is approximately 450°C and working speed is about 4-5 metres a minute.

For cold welding the seam must be cut tightly to produce a strong seam, and it is essential to prevent the cold welding agent from contaminating the floor surface. Follow the relevant manufacturer’s instructions.

For advice on suitable adhesives, contact Armstrong’s Technical Department on 01642 768660.