Share
Do it yourself

Building an Interior Wall

The addition of an interior, non-load-bearing wall is a simple and affordable project. It will allow you to update the layout of your house by creating an extra room or dividing an existing one.

Before you start, decide on the location

The location of the new wall depends in part on the alignment of the ceiling joists.

If the joists are perpendicular to the line of the new wall, you can install it almost anywhere, preferably against a stud in the existing wall (the one into which the new wall will be anchored).

If the ceiling joists are parallel to the line of the new wall, its location will be determined by the joist near the intended location.

In most cases, it's not necessary to anchor the new wall on the floor joists. However, if you are able to do so, the wall will be even more solid.
1

Mark the location of the new wall on the ceiling

  • 1.1 - With an electronic stud finder, find the alignment of the ceiling joists along the intended line of the new wall.
    • If the joists are perpendicular, determine the location of the stud in the existing wall and mark the location of the centre of the stud, along its entire length. This mark identifies the starting point of the new wall line.
    • If the joists run parallel to the new wall, go to the next step.
  • 1.2 - Place a square flat on the ceiling with one of its edges touching the existing wall so that the right angle is lined up with the centre line of the stud previously marked.
    • If the new wall is being fastened to a single joist, line up the right angle with the centre line of the ceiling joist.
  • 1.3 - With the square, trace a line of at least 18" long on the ceiling.
  • 1.4 - Snap a chalk line over the existing line and mark the rest of the wall line. If the new wall is anchored to a single ceiling joist, fasten a second small nail to the centre of the joist where the new wall will end.
  • 1.5 - Wrap the chalk line around the nail and mark the line. This way, the line will span along the entire length of the joist.

The right quantity

Buy the right quantity of gypsum boards for your wall by using our calculator.
Drywall calculator
2

Mark the location of the new wall on the floor

  • 2.1 - Trace another line along the floor, directly underneath the wall line on the ceiling.
  • 2.2 - Then, fasten a small nail at each end of the ceiling line and hang a plumb bob from each nail. The plumb bob pointer will indicate the location of the extremities of the ceiling line. Mark these two points on the floor and snap a chalk line.
    • If the new wall is perpendicular to the ceiling joists, find the exact location of each one and mark it along the lines made previously. Repeat for the floor joists.
  • 2.3 - Also, mark both sides of each joist with a 6" line so you can locate these marks once the plate is in place.
    • If the joists are parallel to the new wall, mark the location of the stud in the existing wall along the lines of the new wall.
    • If the joists are perpendicular to the new wall, go to the next step.
  • 2.4 - Mark the edges of the stud with 6" lines, as previously done with the joists.
3

Install the plates on the ceiling and floor

  • 3.1 - With a circular saw, cut each plate to the required length.
  • 3.2 - Align its centre along the floor line and screw the plate on the 6” marks. Then, screw the top plate.
4

Install the studs

  • 4.1 - Measure the distance between the two plates along the existing wall, then cut the first vertical stud to length.
  • 4.2 - Place the stud between the two plates, making sure it's vertically level, and screw it to the stud or cross stud of the existing wall. Screw it to the plates as well.
  • 4.3 - Mark the two plates every 16".
  • 4.4 - Measure the distance between the plates on the first mark and cut the second stud.
  • 4.5 - Place the centre of the stud on the marks made on both plates, then screw it.
  • 4.6 - Repeat for the remaining studs.
  • 4.7 - After, solidify the edge of the wall by screwing a second stud against the last stud, from the inside.
5

Install the cross studs at the centre of the studs

  • 5.1 - Snap a chalk line along the studs, at equal distance between the floor and the ceiling.
  • 5.2 - Measure the distance between the faces of the first two studs and cut a cross stud to this length.
  • 5.3 - Align its centre along the chalk line and screw it in place. Repeat for all the cross studs.

Don't forget!

Before installing drywall panels, hire an electrician to install electrical wiring, outlets and switches, if necessary.
6

Finish the wall

Suggested products