As with vinyl coverings, thought and planning must be given to carpet installation to achieve a good standard of finish as well as being economical and practical. Again, when measuring out a room, a waste factor must be allowed for in both laying and pattern matching. Careful consideration must be given to areas where there are joints, moving them as much as possible away from traffic areas.
Before cutting any material, a carpet fitter should lay out the first strip and take note of the pile of the carpet, colours and patterns. The ultimate aim of carpet fitting is to create a continuous length and flow, thus creating the impression when the installation is complete, that the dividing walls were built after the carpet was fitted. Careful attention must be paid to the roll numbers or dye batch numbers of every roll of carpeting to be used, and from which roll each strip is to be cut. This minimises the visibility joints, shading and pattern run-out.
The most common method of fitting carpets is the “tackless” method, this being where no tack marks are visible on the surface of the carpet. This is achieved through the use of a carpet gripper made of strips of plywood 6mm thick, 285mm wide and of varying lengths. Specially designed pins penetrate the plywood at a 60° angle facing towards the wall and staggered in two rows along the length of the plywood. The pins are zinc plated so that they do not rust and leave stains on the carpet. The carpet gripper is anchored to the floor.
A pre-heated, special thermostatically controlled joining iron is then inserted under the carpet and moved slowly underneath the joint. The joint would bond to the molten thermoplastic adhesive and can be stretched and manipulated within five to ten minutes depending on the room temperature.
When the joints have cooled, fitting can commence. The technique varies slightly between tufted and woven materials, but basics remain the same:
Choose a corner from which to work – this could be any place on the floor where two rows of temporary nails can be driven into the floor at right angles.
Hook the carpet onto the gripper pins from the corner by sliding the side of the head of a carpenters claw hammer at a 45° angle from the corner until the head passes onto the line of the gripper. Repeat this action radiating outward from the corner in each direction for approximately 400mm.
Using a blunt bolster or chisel approximately 75mm wide, tap the edge of the carpet into the gully between carpet gripper and wall. If there is an overlap, leave this up against the wall at this stage.
The carpet is now firmly held on the gripper pins and can be stretched by means of a power stretcher or knee kicker down each of the two walls from the corner.
The carpet is first stretched across its width, always working away from the starting corner. The tension is maintained by either hooking the carpet onto the gripper pins in the opposite corner, or by the use of temporary nails
The tensioned edge of the carpet is then hooked onto the gripper teeth using the claw hammer
Repeat the procedure, stretching the carpet along its length
Ensure that all ripples are out, patterns and joints straight and all edges hooked onto the gripper pins.
Trim the overlap in doorways and other areas where no quadrant is fitted using a sharp trimming knife.
Trim any excess carpet leaving an overlap equivalent to the thickness of the carpet and force this into the gully between the gripper and the wall. This effectively tucks the carpet under and leaves a clean edge which will not unravel.
Tuck the overlap under the lip of the metal edge and tap down with a rubber mallet or hammer and wood block.
The amount of stretch required to achieve the desired ripple free finish would depend on the type of carpet being fitted. Tufted material, as a general rule, needs to be pulled tighter than woven as shrinkage is minimal when it is subject to moisture.
When fitting carpets on stairs, a good quality underlay is essential. When metal stair nosing is used, the underlay would be cut back approximately 5mm from the edge of the stair. If no nosing is being used, then the overlay would have to overlap the stairnose by approximately 75mm. The underlay would be held in place by stapling, tacking or pasting. The pile of the carpet should always run down the staircase to improve wear.