These can sometimes be cured by dusting talcum powder down between the edges of the boards. Boards that are noticeably loose however, should be screwed through to the joist underneath to pull them tight. If you cannot get a good fixing at the end of a board, nail a small piece of wood to the side of thejoist on which it rests and screw the board to this instead. Be careful not to pierce pipes or wires that run underneath.
Gaps between floorboards can be filled with papier mache made from shredded newspaper and wallpaper glue, with added wood stain if necessary. Force between the boards with a filling knife. When dry and hard, this mixture can be sanded smooth. To fill large cracks, cut fillets of wood to size, glue into place and plane flat. Fill gaps between floorboards and skirting with a branded filler, or nail quadrant moulding around the edge. Use panel pins at 15 cm intervals, and mitre the corners neatly.
If a wooden floor is very uneven and full of gaps, you could consider covering the whole surface with sheets of hardboard. Small sheets are easier to handle than large ones. Before you lay the hardboard sheets, spread water on the mesh side of the boards with a large old paintbrush and leave them to dry for 48 hours stacked flat back to back in the room in which they are to be laid.
Use 15 mm annular nails to fix the boards; these have rings around their shanks to stop them working loose. The boards must be nailed down at 15 to 23 cm intervals all over their surface, working from the centre of the board outwards. Punch the nail heads slightly below the surface of the board. The boards can then be sealed with a minimum 3 coats of polyurethane sealant, or covered with a flooring to your choice.
Uneven solid floors of, for example, quarry tiles or concrete can be levelled with a ‘self-levelling compound’ available as bags of powder from D.I.Y. shops or builders’ merchants. Mix this with water and spread it over the floor, where it will settle to form a smooth level surface. But do not use these compounds for wood or wood-block floors.