Before laying carpet it is essential to prepare the sub-floor carefully to make sure it is dry, level, flat and clean. Any bumps in the surface will cause the carpet to wear prematurely and unevenly.
Preparing the sub-floor
Clear the room of furniture and inspect the floor thoroughly, walking all over it to check for squeaks, uneven or loose boards and protruding nail heads. If there are any signs of damp or rot, deal with the problem immediately.
Loose and squeaking floorboards
Squeaks below a fitted carpet are irritating and not easily remedied once the carpet is laid. They can indicate the nails securing the boards are working loose, causing a floorboard to rise and fall when walked on. Some squeaks may be cured by sprinkling talcum powder or French chalk between the boards. Where squeaking persists, if the boards are loose, secure them with screws. First sink protruding nails below the surface with a nail punch. Drill countersunk clearance holes through the boards for the screws, about 13mm from each nail head, drill pilot holes into the joists and tighten the screws firmly, making sure the heads are below the surface. Always be careful when hammering nails or inserting screws into floorboards. If you are doubtful about what lies below. lift the board and make sure there are no pipes or wires nearby.
Levelling the surface
Check for any sharp edges or uneven boards. Where possible, plane down protruding boards flush with the surround. If, as sometimes happens. a board cannot be levelled off completely. at least round off any sharp edges. Fill any wide gaps between boards with wedge shaped wood strips, cut to length and coated on both sides with woodworking adhesive. Tap the strips down firmly and plane down any protruding edges. Fill smaller gaps with mastic. If the floor is very uneven and cannot be levelled successfully, cover it with hardboard or replace the boards. Level concrete with screeding compound.
Do not lay carpet over thermoplastic tiles unless you have taken measures to eliminate condensation in the room. Otherwise the tiles will ‘sweat’ and moisture will work through to the carpet, causing mildew stains on the pile. Never use rubber or foam underlays over thermoplastic tiles always choose felt.
When the subfloor has been prepared, clean it thoroughly.
Check to see if the new carpet will raise the floor level to a point where the door will not pass easily over it. The door must clear the carpet completely; if it brushes over it as it opens and close it wears the pile. The solution is to remove the door and plane off enough from its bottom edge to ensure it clears the carpet. Do this before laying the carpet since it will make the job easier; even if the door does not need modifying it is easier to lay carpet with the door removed.
Lying the carpet
If you are using carpet grippers to secure the carpet, fix them in position around the edges of the room and fit a binder bar in the doorway (as described). Take the carpet into the room, open it up fully and position it roughly with excess carpet lapping up the walls, it is usual to lay the carpet with the pile leaning away from the light sine this prevents uneven shading in daylight which may be particularly noticeable in the case of plain carpets. If the carpet has a definite pattern, this should be the right way up as you enter the room.
Fitting the underlay
When the carpet is arranged, roll half of it back to expose half of the floor area This is to enable you to put down your underlay one half at a time. If you try to put down all the underlay and then the carpet, you will almost certainly disturb the underlay as the heavy carpet is dragged over it. If you are using felt paper, lay it in strips across the room, but doing the edges with self-adhesive tape. Trim the edges of the paper to butt against the carpet grippers. Stick it to the floor with double sided adhesive at the edges of the room and around any projections. An alternative method of fixing felt paper is to use latex adhesive applied from a washing-up liquid bottle. Put down the underlay in strips across the room, joining the edges with self-adhesive tape. To do this, turn the two lengths of underlay reverse side up and butt the adjoining edges. Remove the protective paper from the tape and press the sticky side down along the joint. Fix the underlay to a timber floor with tacks or staples with adhesive to a concrete floor. Trim it to butt up against the carpet grippers. Unroll the carpet to cover the floor and roll up the other half, laying the felt paper and underlay as before. Finally, unroll the carpet again to cover the entire floor.
Fitting a stretched carpet
If possible start fitting the carpet in a corner where you have a reasonably uninterrupted run of walls, that is, without recesses radiators or other obstructions. During the initial positioning try to leave only about l0mm of carpet lapping up against the starting walls. This will save you having to trim these two edges.
Starting edge technique
A special method is used to engage the starting edge of the carpet onto the carpet gripper to ensure the carpet is firmly held during stretching Using the fingertips with steady downward pressure press the edge of the carpet
along the wall onto the back row of pins. With a hammer, press the surplus carpet down to form a U shape of carpet between the gripper and the wall. The starting edge technique is used along the first two walls to be fitted; the carpet is hooked along the other two walls by stretching.
As work progresses, use a knee kicker (as described earlier) if the carpet needs to be stretched. Stretch one part of the carp€t and hook it into the pins. Move along a few feet and stretch the next portion, continuing in this way until all carpet is gripped.
Check the carpet carefully tor make sure it is evenly stretched- Distorted pattern lines and crooked seams indicate faulty stretching. If the carpet is plain unseamed faults are not so obvious; look closely to see if the pile is running straight. If there are any distortions, unhook the affected part and re-stretch it. Do not hook the carpet onto any binder bars at this stage.
Trimming the carpet
Trim the carpet with a sharp trimming knife. At straight edges take off just enough surplus to leave a 10mm overlap to be pressed behind the carpet grippers. Use an awl or spoon handle to turn the trimmed edge into the gulley.
Right angle projection
Press the carpet into the front edge of the projection, using a length of hardboard to hold it firmly in the angle between wall and floor. Trim along the front edge with a knife, leaving about a 25mm overlap to avoid overtrimming – you can trim it accurately later. Fold back the carpet towards you. Place a piece of hardboard underneath to protect the carpet below and cut it to fit from the corners of the fireplace, or projection, to the wall; still leave about a 25mm overlap.
Cut slits in the carpet at the corners of the room and any right-angle projection so the carpet lies flat around the corner. Stretch the carpet onto the carpet gripper and trim.
Lap up the carpet against the front of the pipe, apply latex adhesive to the back of the carpet at roughly the centre of the pipe and cut a slit in the carpet. Ease the carpet round the pipe and tuck under the edges. For large diameter pipes, it is better to use a card template or a shape-tracer to draw the outline of each half of the pipe on the corresponding sides of the split in the carpet. Cut out the shapes and ease the carpet round the pipe.
Fitting carpet to binder bar
Tuck the edge of the carpet under the lip and stretch the carpet onto the hooks . Place a piece of hardboard onto the lip to protect it and hammer the lip down.
Joining seams with tape
Although carpet suppliers will seam body widths for you, you may find you have to make a seam to fit carpet into a recess. You may need to make seams if you move house and fit your old carpet into a different shape room. Professionals use stitching or heat-bonding to join seams, but the simplest method for the amateur is to use 50mm carpet tape and latex adhesive.