How to Remove and Replace Mobile Home Floor Joists – Full Instructions.

Finished floor project

Replace Mobile Home Floor Joists – Overview Of The Main Steps.

  1. Remove the carpet or flooring.
  2. Cut the sub floor and remove the panels.
  3. Cut and remove the damaged floor joists.
  4. Check the condition of the rim joists.
  5. Support the side walls of the home.
  6. Remove the damaged joists.
  7. Replace the damaged floor and rim joists.
  8. Run cripple studs over the “I” beam rails and around walls.
  9. Replace any damaged insulation batts.
  10. Lay the new sub floor sheets.

List of Materials Needed To Replace Joists.

  1. Lengths of 16 FT 2″ x 6″ timber for Joists.
  2. 1″ x 4″ timber for sill plate.
  3. Sheets of 8′ x 4′ plywood.
  4. 2″ x 4″ studs for cripples.
  5. Roll of 15lb roofing felt or tyvek.
  6. Nails or screws.

What Tools and Equipment Will I Need For The Job?

  1. Pencil
  2. Tape measure
  3. Hammer
  4. Tri square
  5. Chalk box
  6. Pry bars
  7. Skill saw or chop saw
  8. Nail gun
  9. 12 ton bottle jack
  10. Compressor and hoses
  11. Impact driver and bits

The Steps In More Detail.

Remove The Carpet Or Flooring.

Roll up the carpet to reuse it later.

If the carpet is being replaced, cut it into 4′ wide strips  and bound with duct tape for easy disposal.

Wooden flooring should be removed and stacked away from the work area.

Remove The The Sub Floor Panels.

Unscrew or use the prybar to loosen and remove the floor panels for later use.

If the floor is damaged cut the center of the boards to help with removal.

Remove any nails or staples from reusable joists.

Removing the floor joists completed

Remove The Damaged Floor Joists.

Inspect and remove the damaged floor joists.

Use a hammer and prybar to help with removal.

Cut the joists in half and twist to remove from the rim joist.

Remove any old nails or obstructions.


Check The Condition Of The Rim Joists.

The rim joists run around the perimeter of the floor.

They connect to the ends of the floor joists and support the stud walls and ultimately the roof structure. When the floor joists are damaged often the rim joists need to be replaced also.

broken center sill to replace

Support The Side Walls Of The Home.

If the walls have dropped down in a few places you may have to relieve some of the weight on the wall. Raise the wall in order to get the rim joists/floor joists in place.

To do this place a bottle jack and a 4″ x 4″ post under the wall footer and raise it slowly into place.

Replace The Damaged Floor And Rim Joists.

Measure and cut the floor joists to length. Measure each one separately for accuracy.

Mark off the 16″ o/c positions in the rim joists with a tape and pencil.

Offer up each joist into position and temporarily toe nail the joint to hold in place.

new floor joists installed

Run Cripple Studs Over The “I” Beam Rails And Around Walls.

Place cripple studs:

  • Between the floor joists over the top of the I beams.
  • Where the ply meets the walls.
  • Anywhere the ply wood joints will land not directly over a joist.

These extra studs will help to stop the floor joists twisting and give support at the plywood joints.

Cripple studs installed

Replace Any Damage Insulation Batts.

Replacing insulation panels can be done now or from beneath the home after the plywood has be fixed to the floor joists.

Lay The New Sub Floor Sheets.

Lay the new plywood sheets in a brick pattern to stagger the joints. Make sure that all nails or screws hit the floor joists.

Nail or screw 16 inches on center at all joists.

Which Way Do Floor Joists Run in a Mobile Home?

The floor joists in a mobile home run perpendicular (90 degrees) to the “I” beams. They span the gap between the side walls on a single wide and the center to the sides on double wide homes.

How Far Apart are the Floor Joists in a Mobile Home?

The floor joists are usually 16 inches on center although I have seen some as close as 12 inches o/c and as far apart as 24 inches o/c. These 3 measurements work out best with 8′ x 4′ sheets of flooring.

new joists at 16 inches on center

The joists support the sub floor which is usually made from plywood or oriented strand board (osb).

The depth (2″ x 6″ / 2″ x 8″) of the joist and its ability to support a load will determine the distance between floor joists.

The Center and Perimeter Rim Joists?

The wood that runs down the center line and the side walls of the home at right angles to the joists is called the rim joist . The rim joist connects together the ends of the floor joist and helps to support the walls.

If the rim joists are damaged or rotten there will be nothing to connect the floor joists together. If this is the case the rim joist will need to be replaced as the joists are rebuilt.

In many cases some of these will need to be replaced.

How Much Does it Cost to Replace Joists in a Mobile Home?

The cost of replacement will include the labor and materials or just the materials if you are doing the job yourself.

The cost of an 8ft 2″ x 6″ is around $15 per piece.

The cost of an 8ft 2″ x 4″ is around $6 per piece.

Labor will be around $50 per hour.

If You Need To Have Your Floor Repaired.

Call 863 808 2200 or send us a message using the contact page.