Laying floorboards onto joists

LAST UPDATED: 25th August 2023 by The Editorial Team

Laying floorboards onto joists

Summary: Step by step guide with video showing how to lay floorboards onto joists, lay square-edged boards, lay tongue-and-groove boards, cut around obstacles and cut around a permanent fixture.

How to lay floorboards

When choosing floorboards, you will have to decide whether you want square-edged boards or tongue-and-groove boards, which have concealed fixings.

Preparation

  • Locate any under-floor cables and pipes.
  • Leave new floorboards in the room for 3 days to shrink or expand according to temperature and humidity.
  • Lay a plank or sheet of chipboard across the joists to give you a platform to kneel on while you work.
Use two fixings at each point where the board crosses a joist.

Fit wedges over a joist in the gap between the fifth and sixth boards and a hammer to knock them together.
You will need to cut and scribe the last row to fit neatly against the wall.
Lay a board across the joists, leaving a 10mm expansion gap between the board and the walls.
Loosely lay the next five rows in place and leaving a gap temporarily lay the next board.
Repeat at the end of the boards and in the centre to ensure there is a tight joint along the whole length of the boards.

Square-edged boards

Before you start, follow the recommended requirements for board sizes.

  • Cut over-long boards to size.
  • Start at one end of the room and lay a board across the joists, leaving a minimum 10mm (3/8in) gap between the board and the walls to allow for expansion. See the advised expansion gaps for different woods.
  • Insert thin strips of wood along the length of the wall to maintain the gap.
  • Fix the board to the joist with nails or screws, using two fixings at each point that the board crosses a joist.
  • Use a nail punch to knock the head of the nails beneath the surface of the board.
  • If your board does not reach across the width of the room, join two boards end to end over a joist, so that the ends of the boards are supported by half the joist.
  • Loosely lay the next five rows in place. Leaving a gap temporarily lay the next board.
  • Clamp the first six rows together by using a floor clamp, which should be attached to a joist with the grip against the nearest board.  By turning the handle of the clamp the boards will be pushed together creating a tight joint.
  • Alternatively you can clamp the boards together using triangular wedges. Cut two triangular wedges from an offcut of board.
  • Fit the wedges over a joist in the gap between the fifth and sixth boards. Use hammers to knock the wedges together, which will force the floorboards together. This will have to be repeated at the end of the boards and in the centre to ensure there is a tight joint along the whole length of the boards.
  • Whatever method you use, once the boards have been tightly clamped together, nail or screw each board securely to the joists.
  • Lay the next five rows of board and repeat the process.
  • On reaching the opposite wall it will probably be necessary to cut and scribe the last row to fit against the wall using a jigsaw.

Tools needed

  • Panel saw OR jigsaw
  • Claw hammer Or screwdriver
  • Nail punch
  • Floor clamp

Materials needed

  • Square edged floor boards
  • Nails OR screws
Fix the board to each joist by driving a nail into the tongue of the board at a 45º angle.
If your boards do not stretch across the room, the ends must butt together over a joist.
Cut and scribe the final board and secure using round lost-head wire nails.

Tongue-and-groove boards

The method for laying a tongue-and-groove floor is similar to that used above. Tongue-and-groove does not have to end on a on a joist as long as the joists are not further apart than 350-400mm (14in – 16in). Before you start, follow the recommended requirements for board sizes and tongue-and-groove boards.

  • Cut over-long boards to size.
  • Start at one end of the room and lay a board across the joists, leaving a minimum 10mm (3/8in) gap between the board and the walls to allow for expansion. See the advised expansion gaps for different woods.
  • Insert thin strips of wood to maintain the gaps.
  • Fix the board to each joist by driving a nail into the tongue of the board at a 45º angle just below the straight edge of the board.
  • Recess all nails with a nail punch.
  • If your boards do not stretch across the room, position two boards so that the ends butt together over one joist.
  • Place the next board so that the groove-edge interlocks with the tongue on the first board and hides the nails.
  • Continue to lay rows of boards, nailing the tongues to the joists.
  • Cut and scribe the final board to fit.
  • Secure the final board invisibly using round lost-head wire nails.
  • Draught-proof and seal the floor.










Cutting around obstacles

Mark the position of the pipe on the boards, then push together and drill a hole over the markings.

To cut a hole for a pipe:

  • Cut two sections of board to go each side of the pipe.
  • Mark both sections where they touch the centre of the pipe.
  • Push the sections together and drill a hole over the markings. To drill a hole of the correct diameter, use an off-cut of pipe that is the same diameter as the pipe you are cutting around as a template. Alternatively, just start with a small bit and keep enlarging the hole until the pipe fits between the two sections.



Use a paper template to mark the shape on your board.

Cutting around a permanent fixture such as a basin

  • Cut two pieces of board to go each side of the object.
  • Cut two sheets of paper to the same width as the board.
  • Place the paper sheets on the floor on either side of the object and fold the paper around the object. Use scissors to cut tabs in the paper to make folding easier.
  • Draw around the basin at the base of the tabs and cut out this shape to make a template.
  • Use the templates to cut each of the boards to the correct shape.

Tools needed

  • Jigsaw
  • Claw hammer
  • Nail punch

Materials needed

  • Lost-head wire nails

Laying new floorboards video

Video showing how to remove floorboards and replace with new boards.

Author

The Editorial Team

The Editorial Team at lets-do-diy.com are a team of experts led by Mark Wilson. We have been creating DIY projects, articles, costs guides and product reviews since 2008. For more info see our about page.