How to Reinforce Bathroom Floor Framing

Reinforcing bathroom floor framing can be a very tedious, and time consuming job, but it is well within the abilities of most homeowners to complete. The time involved in this type of project makes it an expensive venture when hiring a professional. To save some money, gather the following list of items and do the job yourself.

Tools and Materials You'll Need:

  • Hammer
  • Crowbar
  • Tape measure
  • Sheeting nails
  • Framing nails
  • Sister joist framing boards
  • Jigsaw

Step 1: Remove the Existing Subfloor

Before being able to reinforce the floor framing in a bathroom, the existing subfloor must be taken out. If you are planning to reinforce the entire room, then all the fixtures must be taken out as well. Turn off the water supply to the bathroom. Disconnect the plumbing fittings on the fixtures and remove them. The toilet, as well as the cupboards, can be taken out by removing the securing bolts and screws. After the fixtures and cabinets have been removed and taken out of the way, the subfloor can be taken off. You may have to run a power saw along the outer edges of the flooring to remove the sheets, depending upon how the original framing was done. Next, use the hammer and pry bar to lift the existing sheets off of the joists that run below it. Take care when doing this so that if the subfloor is reusable, you can nail it back down.

Step 2: Add the Sister Joists

After the joists are exposed, use a tape measure and get an exact measurement of the width and length of the exposed joists. Cut some of the framing material that you have purchased to length. Secure the new piece of wood to the existing joist by using framing nails. Repeat this step with all of the exposed joists. If any pipes or electrical wires are in the way, take measurements and cut circles out of the wood with the jigsaw. Make sure that the holes are not too large, as too large and opening will lower the strength of the new sister joists.

Step 3: Replace the Subflooring

After the joists have been reinforced with the sisters, the subflooring can be put back down. If you were able to salvage the old flooring, then place them on the joists. Attach them down with the sheeting nails, but make sure that you do not place the nails in the holes that were previously used because it will not hold the sheets securely. If you have to cut new pieces, do so and then nail them down. When laying the sheets out on the joists be sure that the edges off the wood end in the middle of the joists, and always stagger the seams for added strength. After the subflooring is secured into place, the fixtures need to be put back in. Follow the exact steps that you followed when taking them out, except in reverse order.