Sistering Tji Floor Joists

All i can find in my code.

Sistering tji floor joists.

Here is a pathetic attempt to splice some floor joists under the bathroom. Framing lumber is the typical. However if the loading is applied from above through floor sheathing through a load bearing wall or post that rests on both joists then no attachment between joists is required. Trus joist tji joist specifier s guide tj 4000 july 2019.

My question is can floor joists be spliced or sistered properly. Doing so strengthens weak joists and can help straighten sagging joists. Fire safe construction 3 floor performance and tj pro rating 4 5 section 1. Drooping and joist sag can be seen in the photo.

It s floor joists that are approximately 8 feet long made from 2 floor joists approximately 4 1 2 feet long. Where the two pieces of floor joist meet they aren t nailed together or have one or two nails. In situations when sistering damaged floor joists with lumber of similar dimensions it can be easy to notch and slide the sister board into place. Depending on how the load is applied it may be necessary to connect the two joists together with a filler block.

I ran across this today. Size alongside each existing joist also known as sistering the joists stiffens a floor. However doing this does not fix the slant that the floor has taken since the old joists got damaged. When headroom permits sistering with taller joists provides more bang for the buck than sistering with same size joists.

Believe it or not this kind of poor workmanship is not that uncommon. Sistering joists means beefing them up with additional material. Tji joists are occasionally doubled to support other members or loads from above. The long view makes the overlap seem longer but i believe the nearest one is less than a foot with very few nails.

If so how might it be done. If you have sagging cracked or twisted joists which can happen in older houses this project will provide the extra support the floor needs. Take some extra time and jack the damaged area up so that the new lumber doesn t need to be notched. Even though taller joists need to be notched to fit existing mudsills and support beams photo right the added depth.

How to sister a floor joist.