How to Lay Chipboard and Ply Floorings
Layingand Ply Floorings
Chipboard or may be used as a cheaper substitute for floorboards when laying the subfloor of a room. Many new houses are already being built with floors made from such sheet materials. Plywood is dimensionally stable so makes an ideal base for other floor coverings such as laminated floors and tiles. Whilst it is possible to lay and ply over existing flooring, bear in mind that this could make access to underneath the floor difficult in the future.
Tools for the Job:
- tape measure & pencil
- cordless drill/driver
- or circular saw
- carpenter’s square
- nail punch
Flooring grade chipboard is generally 18mm (11/16in) thick and comes in sheets 2.4m x 600mm (7ft 10-1/2in x 2ft). Tongue and groove joints provide extra support to the edges. Larger sheets makes it much quicker to lay than standard timber floorboards.
- Chipboard floors are most likely to be fitted directly to joists. Lay one or two boards down without fixing them to walk around on.
- Lay the first board at right angles to the run of the joists, starting in one corner. Ensure that the board is placed with the tongue facing away from the wall, and note that all boards should be laid printed side down.
- Screw or nail the board in place. Screws should be 25mm (1 in) longer than the flooring thickness, so a floor 18mm (11/16in) thick will require 32mm (1-3/8in) . Drive these in at 200mm (8in) centres. Make fixings no closer than 50mm (2in) to any edge.
- Run a bead of PVA into the end groove of the next board and push this up to the first board. Endure the joint is tight with no gaps showing on the face where the two boards meet. If hand pressure alone is not enough, tap the end of the board with a hammer. Insert a scrap of wood between the hammer and board to avoid damaging the tongue.
- Carry on till one row is finished hen start on the next. If the last board of the first row was cut to length then start from this end on the second row in order to stagger joints. Do not worry if joints do not occur on joists as the tongues provide support.
- Cut the last boards to width 1cm (1/2in) less than the overall measurement. Run into the groove of each board and place them onto the joists tight against the wall. Force the board onto the tongue of the next board with a prybar.
If using a circular saw to cut flooring, wear appropriate safety equipment. Safety glasses or goggles keep dust and splinters out of your eyes. Wear a dust mask if working in enclosed spaces or, better still, cut the boards outside if you can.
Very popular in the USA, plywood is often used as a quick method of covering a floor. It provides a very stable and strong subfloor over which tiles, carpet and almost any other floor covering may be laid. Stronger than chipboard, it is better suited to damp environments and can withstand greater weights being placed upon it. If better quality ply is used it can even be varnished and left without any additional floor covering.
- Ensure the plywood is laid to best advantage. If sheets are being laid over an existing floor then where the joints fall will not matter. Where ply is being laid directly onto joists the joints must fall onto a joist. Lay down a few sheets dry, orienting them in different directions to check.
- Newer houses have joists placed at close spacing. In older houses floors tend to be constructed using joists with a larger section but spaced farther apart. Fit noggings to reinforce ply edges where necessary, providing additional support. Use 75 x 50mm (3 x 2in) timbers on edge cut to fit between the width of the joists. Skew nail on each side, through the top of the nogging and into the side of the joist. Keep the top of the noggings level with the joists.
- Boards can be fixed down by hammering wire into the joists and punching the heads below the surface. Alternatively, by drilling pilot holes and screwing them down, gaining access below the floor will be that much easier. Place screws at 200mm (8in) centres with no closer than 15mm (5/Bin) to any edge.
- Fit the remaining boards, maintaining a 2mm (1/8in) gap along all joints to prevent the boards from squeaking and to allow for any slight movement. Cut a couple of pieces of scrap timber 2mm (1/8in) thick and place these between the boards to keep the gap consistent as you fit. It also saves having to keep checking the measurement repeatedly.
- Replace the skirting if this was removed, or install it now if fitting new skirting. Press it down to the floor as you fix it to the wall but do not insert fixings into the floor. If the skirting was left in situ, install a small quadrant or Scotia moulding to hide the joint between ply and skirting.
Tips of the Trade
Running a small bead of mastic around the room will seal the joint between any skirting board or moulding and the floor. This helps to prevent dirt and dust from finding its way into the room and soiling carpets or other floor covering.