Roof truss and rafter repair

[Guest]

Need some suggestions on the best way to repair inside trusses and rafters.

Home is 1968 12x60 SW, several areas need repair as the ceiling tiles are sagging down and unable to push back up.

[JD]

Hi Jim,

In a previous post you were talking about replacing the ceiling panels with paneling. This would be a good time to repair those trusses. On trusses with a flat ceiling, you will find very minimal wood used for the trusses. In order to straighten and strengthen the trusses you would need to go through the ceiling or through the roof. Removing the ceiling and salvaging the panels is difficult but can be done. Replacing the panels with paneling or sheetrock would make this step easier.

After removing the ceiling panels you will probably be able to see what is wrong with the truss. Sometimes a top or bottom cord is broken and sometimes they are just pulled apart. I will cut a piece of 3/8" cdx plywood into the correct shape of the truss. I usually make it 1/2" smaller in size to make it easier to install without sticking out past the truss. Basically, this plywood piece is sistered to the side of the truss. First I will staple (heavy narrow crown, sheetrock screws would work) the plywood to the top cord. If the top cord is bowed or broken, I make sure to fit it to the proper shape while fastening. Then to push the truss up into the correct position and straighten the bottom cord, we use a 4x4 covered with carpet held up lengthways along the length of the truss. To hold this 4x4 up, we use load jacks, the kind truck drivers use to steady loads in the trailer. You could also use 2x6s cut to right size to jack the truss up. Put a 3-4 ft 2x6 on the floor parallel to the truss, then cut a 2x6 to the proper distance between the floor and ceiling, minus 4". This will allow for the thickness of the 4x4 and about an 1/2 inch of the 2x6 on the floor. Wedge the 2x6 between the 2x6 on the floor and the carpeted 4x4 and drive the bottom of the 2x6 with a hammer. The 2x6 on the floor allows the vertical 2x6 to skid along without hurting the floor. You will need two load jacks or 2x6 apparatuses, one at each end of the truss. Jack the truss up into position, plus about 1/2" and then staple the bottom cord to the 3/8 plywood. One thing about installing the plywood. You need to determine the best location of the plywood to splint the problem area of the truss. You also do not want to totally close off the "attic" area at the truss. You need to allow airflow around the 3/8" ply. If you need to install a full 12' of plywood to keep the truss straight, drill a bunch of holes in the plywood with a large hole saw to allow airflow.

My explanation may make this repair sound difficult, but that would be because of my explanation rather than the repair. I find this repair much easier than building a replica truss and replacing the damaged truss with it.

You can usually repair 3 trusses with one $12 sheet of plywood and after you get the hang of it, they will take about an hour or so a truss.

Hope this helps.

JD

[JD]

You jack the truss up 1/2" higher than the ceiling height because it will usually relax down about that much. This repair will greatly improve the looks of the ceiling, but probably will not be perfectly straight when you are done. Often times there is a little drop in the ceiling near the wall.