Mobile Home Floor Repair

Last Updated 10-31-2005

Floor Theory 101

Cross Section

Fig. 1

Floor Cross Section End View

Cross Section 2

Fig. 2

Floor Cross Section Length View

 

Before you start you need to determine how your floor is put together. I drew up some cross sections of how mine is done. See Fig. 1-2. Yours may be different and use a standard sub floor system of 'normal' joists.

 

The Kitchen

Preparing to Cut

Fig. 3

Preparing To Cut

Opening up the floor

Fig. 4

Opening up the floor

Floor Details 1

Fig 5

Floor Details 1

Floor Details

Fig. 6

Floor Details 2

About Ready for New Floor

Fig. 7

All Open

Duct

Fig. 8

Duct Detail

Trimming Near Wall

Fig. 9

Cutting Under Wall

Flooring Edge Support

Fig. 10

Floor Edge Support Board

Corner Support

Fig. 11

Wall Corner Support

Replacing Particle board with Joist

Fig. 12

Joist Repair 1

Joist Repair

Fig. 13

Joist Repair 2

All Done!

Fig. 14

All Done!

I decided to make this page more of a 'how to do it', than a, 'here's what I did' page.  From looking around at other sites I realize this may only apply to older single wide homes like this one. I'll give a step by step of what I did and why I did it. It may not be the best way or the only way but the result is a strong floor.

  1. First determine the extent of the damage. Fig. 3 shows the floor after stripping off the old linoleum. It's not possible to see in this pic but the floors were badly bowed from water damage halfway across the kitchen! I used a 4' level to determine how far back the floor was bowed. I marked on the floor where it stopped bowing. Then I had to try to figure out where the closest main joist to the mark was so I could be sure the edge of the new plywood floor would have a solid support. You will also want to remove the bad flooring over to where a seam is. This makes it easy to replace sections. Thankfully particle board comes in 4' widths just like plywood!
  2. I started by opening up the floor with a reciprocating saw from Harbor Freight so I could see how it was constructed. See Figs. 4-11. This saw set me back the astounding sum of $19.95 + $8.95 for a pack of 20 blades. Have a couple of boards or a section of plywood handy to place across the support boards to walk on!
  3. The rotted particle board just falls apart and can be knocked out with a hammer but when you get back into solid wood it will become necessary to saw it out. Just be patient and cut in between the support boards back to a joist then just break that piece out by hand. The factory uses a staple gun to attach the floor and these staples are a pain to get out. Sometimes the staples will pull free when you break the piece out. Be careful that you don't saw through the joists or support boards!
  4. Once all the old floor has been removed back to the joist you chose and over to a solid seam, remove any staples that remain. Inspect the joists and support boards and repair/replace any that have rotted. See Fig. 12-13. I used a 2 x 4 and a metal floor joist support but you can also just toe nail it in. Cap it with a piece of 6" wide plywood and if necessary shim it to match the particle board height.
  5. To keep the wall from settling into the space where the floor was I removed all the rotted board then cut the nails that were driven through the 2 x 4 into the 2 x 6 with a metal blade on the saw. Now I would be able to slide the new plywood UNDER the 2 x 4 wall sill plate just like the original floor. Note that is is very difficult to remove the good particle board from under the 2x4 wall sill plate and 2 x 6 joist. I used a chisel and hammer to remove it. Another alternative is to cut sections of plywood to fit under the 2 x 4 to support the wall and then cut the flooring to fit flush with the edge of the wall not under it. Either way will work.
  6. If you have a wall that runs perpendicular to the cut out floor then remove the base board, place masking tape on the wall to protect it and use the sawzall to cut as close to the wall edge as possible. Angle the saw as necessary You must get the floor cut flush to the edge of the wall or you will have a large gap there! Now nail a 1 x 2 or a 1 x 4 board to the joist flush with the wall. This will give the new floor support on the edge. See Fig. 10 and 11 above and Fig. 21 below.
  7. Now we are ready to cut our new pieces of plywood to fit the floor. Measure twice and cut once! In order to keep the seams gaps as narrow as possible take care when ripping long cuts. Snap a chalk line as a guide or if you are not good at long cuts with a circular saw then clamp a good straight edge to the sheet and use it as a guide.
  8. Lay the plywood sheet in place. If you are putting it under the wall you will have to tilt it, slide it under the wall then maneuver it back to close the seam at the joist. Check that all seams are level to each other. If they are not use shims under the flooring to bring it up.
  9. Use 2" deck screws to attach the floor. Yes nails will work fine but they WILL loosen over time resulting in a squeaky floor. Make sure to use a new phillips bit in your drill. Grab a handful of #2 bits while at the local hardware store. Run the screws in at a steady pace and sink them just below the surface of the wood. You will use floor leveler later to fill the depressions and seams.
  10. Before you lay carpet or linoleum run a bead of caulk all around the edges of the new floor to help keep out ants and such.

Under Refrigerator Floor Repair

Fridge 3

Fig, 15

Fridge 1

Fig. 16

Fridge 2

Fig. 17

Fridge 4

Fig. 18

Board 1

Fig. 19

Board 2

Fig. 20

Board 3

Fig. 21

Done!

Fig. 22
  1. Fig. 15 shows the floor where the Refrigerator sits. What caused this floor damage? The drip pan for the fridge was missing! This allowed water from defrosting to seep onto the floor. Over the years this water worked its way under the linoleum through staple holes on one side and through a cut in the floor from when they removed the protective plastic on the other side. Once the floor was weakened the critters knapweed holes through the floor! You can see teeth marks in the wood in Fig. 16 and 17.
  2. In Fig. 18 I have ripped out the old particle board, and am about to start cutting the flooring flush with the walls. Then I can mount 2 x 4 joists that will support the new floor around the edges.
  3. Fig 19 shows one of the new 2 x 4 joists I have attached the joist hangers to. These make it easy to add joists.
  4. Fig. 20 shows the 4 new joists in position.
  5. The plywood cut and screwed down. Another piece of floor repaired!

The Living Room

Living Room Floor Repair

Fig. 15

Living Room Floor Repair

Done!

Fig. 16

Done!

 

I also fixed a smaller area in the living room under a window. I only had to take the floor back to the first joist so it was an easy 2 hour repair.

The Hallway

Hallway Floor

Fig. 17

Hallway Before

First Hole

Fig. 18

First Hole

Done!

Fig. 19

Done!

The hall was also an easy fix, though it took me about 4 hours.

The Master Bedroom

Left Side Floor

Fig. 20

Left Side Floor

Right Side Floor

Fig. 21

Right Side Floor

All Ripped Out

Fig. 22

All Ripped Out

Huh?

Fig. 23

Huh?

I give up

Fig. 24

I give up

Floors are Done!

Fig. 25

Done!

Last but not least was the master bedroom. I started thinking I would make two separate repairs one in each corner. See Fig. 20 and 21. Then I realized that it would be faster to just replace the floor all the way across. Does anyone know if the floor edge 2 x 6 is supposed to sit on top of the out riggers? Fig 23 shows that mine do not. (It does not on the other side either. Remember the crooked joist we found in the kitchen and hallway? Well it continued all the way to the end! See Fig. 24. If the board had been straight up and down the floor would have been over 3/4" of an inch taller there! I came to the conclusion that the welder welded the out riggers too high on the frame on this side and they had to turn the joist at an angle to prevent the floor from being higher than it already was. Would have been a better repair to plane the joist down.

Fig. 24 also shows the tie down straps were not tightened! I looked under the home and sure enough, even though they took the time to drive the anchors into the ground NOT ONE of them was tightned! When I put the plastic under the floor I will tighten them all...

Well this concludes the floor repair on the home.

 

 

 

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