There are few problems in replacing square edged boards. New ones of the same thickness are cut to length and in the case of non standard sizes to width. If part of the board has to be tapered or otherwise shaped to fit, use the discarded board as a template when you saw to shape the new one.

If a single board is to be replaced simply slot it into place and nail down. A number of boards covering a large area are best fitted individually if possible in the same flooring 'pattern' as originally. No two board ends should lie side by side on the same joist.

When fitting a number of boards, do a 'dry run' first to check the width fit, and whether tight butting of the boards is possible. Where the boards are to remain visible, keep to the original spacings for the sake of appearance.

If a complete floor area is being replaced, make a point of butting all boards as tightly as possible before fixing. This is done with a floor cramp, available from hire shops and substantially improves underfloor draught proofing. If part of the original floor boarding is to be replaced, cut off any wood that is badly split where nails were removed. Do not reuse old nail holes. These, and new holes along the length of the board, should be made good with a filler paste.

[edit] Replacing T&G Boards

Replacing tongued-and-grooved boards is not quite so straightforward. If you are re-using the old board, this can be replaced by fitting the remaining tongued or grooved side into the adjacent board. A small gap will remain on the other side, this must be plugged for complete draught proofing.

To fit a new tongued and grooved board, you may have to plane off its tongue to get it to fit, but leave its grooved side intact. If a number of adjacent boards have been removed, any necessary combination of used and new boards may be used when re-flooring. The technique is to loosely fit these together over the floor area to be covered, in the process forming a low arch by making the boards slightly over sized. Lay a spare plank over this, and press or stamp the boards down: the tongues and grooves knit together in the process. The flattened boards can then be fixed in place. Alternatively, you can use an off cut and mallet.

[edit] Replacing Short Sections

If you are cutting out and replacing a short section of floorboard you may want to use up a spare piece of timber lying about the house. Alternatively, you may have difficulty getting a replacement board that exactly matches the thickness of your existing ones. Either way, the new board will be better too thick than too thin.

Having cut your new section to length, lay it beside the gap in the floor and mark off on the underside where it is to pass over a joist. Chisel out rough rebates between the marks, to the same depth as the board, is oversize.

When you lay the board, the rebates should fit over the joists and allow it to rest flush with the others.