Start by cutting out a small 1 2 in 2 5 5 1 cm section of the floor joist with a reciprocating saw.
How to level existing floor joists.
You just have to make sure that the joists can handle the addition of more weight from the plywood subfloor and any additional floor coverings.
This will create a weak spot.
Pry the floor joist from the subfloor with the back of your hammer.
Fixing a floor that sags and dips pour self leveling underlayment in the problem area.
Lay a long level downhill on the floor with one end of the level on the level part of the floor and the other end at the lowest point.
Thre ways to fix a sagging or sloping floor.
You can then smooth it out using a hand trowel and sand the entire surface for a seamless finish.
Simply mix up the compound pour it over the subfloor and wait for it to fill in the lowest spots.
Only raise the jacks about 1 8 inch per.
Depending upon the conditions it is possible to strengthen or repair existing framing members such as floor joists or roof rafters by adding reinforcing material sandwiching the member on either side with plywood is sometimes worthwhile but the plywood must be installed correctly for greatest strength.
If you suspect that you re working with an off level foundation you can get it ready for installation quickly by using a floor leveling compound.
Raise the jacks about 1 8 inch more.
Then a string line can be fixed to the top of these two new joists giving you the level for the joists in between.
You can also lay down new hardwood floor on the top side of the floor.
A plywood subfloor acts as a bridge for minor waves in the existing floor as well as a leveling compound.
Compound can correct sags and dips as deep as 1 1 2 inches.
To level the entire floor it is best to start with the two end joists.
Even though we use 1 pt lumber the joists are often slightly warped or vary in depth at times causing adjacent joists to differ in height by as much as 1 2 inch or more.
Then use pry bars and your reciprocating saw to pry and cut the floor joist away from the subfloor.
They have a strong lip which is then inserted into a brickwork joint or fixed on a timber or steel support.
If the uneven floor is due to floor joists that have warped or twisted over time or were incorrectly installed the only way to level the floor is to remove the subflooring and shim the joists.
If you have access to the basement or crawlspace it is possible to jack up saggy joists until they are level and then sister them so that they remain straight after the jacks are removed.
