You can go for 6 inches if you have space.
How to fix cut off floor joists.
If you have improper holes and notches from alterations and running service lines this can be the source of weakened joists.
Direct nail the first header in to the cut joist and through the trimmer joists in to the header.
There are several variations on how this might be done he says but that s the gist of it in a members only article from issue 232 plumber mike lombardi demonstrates how to fix a failing bathroom floor.
Making a jack post i made a fast and simple jack post with two 2 4 screwed together.
There shouldn t be any cuts or penetrations in the middle third of the joist or at the bottom of the joist either.
Take some extra time and jack the damaged area up so that the new lumber doesn t need to be notched.
Place concrete pads under the cut ends of the joist and install jack posts.
Just to be safe we re going to cut the joists at least 4 inches away from the rotten spots.
At joist hangers a little thin metal welding may be in order.
Remember to wear protective eyewear whenever using an electric saw.
If your floor joists have been cut improperly to install pipes wiring or hvac ducts this could be causing your floor to slope.
Add the second header and direct nail this header through the trimmer joists.
However doing this does not fix the slant that the floor has taken since the old joists got damaged.
If the saw doesn t work on its own use a hammer or crowbar to pry the joist away.
To get the angle under and alongside where joist is let in to wood use a flush cut power tool to make slots for the angle to get in there.
At any area where that won t work shelf angles can be attached to the support steel of concrete.
A metal fabricating shop can produce a.
Thre ways to fix a sagging or sloping floor.
Detach the floor joist from any walls or wires it s nailed to with a saw.
This will make sure that dry rot that isn t visible won t sneak up on you.
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.
If the new joist is hitting a beam and the floor above and jacking is not an option an alternative approach is to cut small bevels on the two opposing edges that the touch the beam and floor board.
The best thing to do is mark your joists that are to be removed.
Bottom reinforcement attaching a metal strap to the bottom edge of the joist can stabilize a notched joist increasing the tensile strength of the joist.
Use a reciprocating saw to cut pieces of the floor joist away from walls.
This helps the joist turn into the proper resting position.