Do I just use white PVA wood glue on the T+G?  I have seen people also run a bead of glue on the joist?

Am I right that as long as the T+G is glues, and correctly fitted, and boards staggered, it does not matter if a joint falls between joists?

Would you nail with ring shanks?  There is no ceiling below.

Do you leave a gap at walls?

Any other advice greatly recieved!

I am replacing a floorboarded floor which is in very poor condition with tongue and grooved chipboard flooring and I have a few simple questions which I can not find the answer to, can you help?
1.      Chipboard comes in 18 and 22mm thickness, which one should I use?
2.      Should the joints be glued?
3.      Do I need to align the joins over the joists?
4.      What is the best way to fix them, nails or screws?

Your help would be appreciated and is there anything else I need to consider?


It is quite an easy job to lay a chipboard floor, the boards are not too heavy but it would be wise to get some help laying them as the relatively thin edges of the boards are easilydamaged. Chipboard floors are renowned for squeaking if they are not fitted properly so firstly you will need to clean up the tops of the joists in order that the boards have a good flat surface to fit to. It is a good idea as you are laying the boards to mark the positions of any pipes or wiring with an indelible pen on the surface of the boards and do not forget to leave a 10mm gap round the edges to allow for movement. As to your specific questions;
1.      The thickness of flooring depends mainly on joist spacing; if the joists are spaced 450mm or less then 18mm flooring can be used. If the joist spacing is 600mm then use 22mm chipboard.
2.      Yes glue all the joints with PVA adhesive, it stiffens the floor and helps to prevent it creaking.
3.      The boards run across the joists so the long joints will not be supported but the short joints should be aligned with a joist, if not you will need to add a noggin to support the joint.
4.      Ring shank nails are often recommended for chipboard floors but I always screw flooring down, it takes a little longer but screws do a far better job. Spax make a screw specifically designed for flooring, Screwfix sell them part no 56710, and they cost £3.96 for 100. Screws should be fitted at about 200mm spacing.

DT that's OK unless you glue the joints, which you should IMHO. If you glue and lose lay, in all but the smallest rooms, which won't run out of square anyway, the glue will set before you get chance to correct any out of squaredness.

woodsmith wrote on Sep 7^th, 2008, 11:40am:






Ha!  You know I meant groove!