How can I level the joists and ceiling?

Question

I am presently renovating a house that has a 4" difference from the middle to the one side due to the subsidence.

It is a semi-detached duplex, with 3 floors including the basement. The worst is the basement and the 1st floor (4" difference). Now the foundation is no longer subsiding because some stakes are driven to the ground. Now I am going to level the floors and ceilings.

I was told the proper approach was to first remove the floor and subfloor, then find the highest joist and draw a level line around the wall at this point. A this point I would have two options:

• Drill holes little bigger than the bolts and sister new joists with old ones with bolts and nuts.

or

• Use construction adhesive to glue the new joists to the old ones.

I have no idea which one is better or maybe neither of them works. I'd like y'all's input. Thanks!

Answer 1

Sistering is a common approach to this situation. However, if it's a multiple-floor building, you should have an engineer involved to make sure that the footings in the basement are now sufficient and that the repairs will properly carry the weight of all the floors. You will also need to figure out how to deal with the internal walls on each of the floors.

To answer your specific question, gluing the joists together and holding them together with bolts is the common approach.

Answer 2

The amount of work to level three sets of floors and ceilings might be equal to having the structure jacked and leveled properly. If, as you say, the foundation is solid, then the jacking and leveling is pretty straightforward. (Admittedly, it's not a DIY kinda thing, which means money instead of sweat.)

Don't forget that when you fiddle with the floors and ceilings, you're losing height in the rooms, which might be noticeable. You'll need new flooring and baseboard. Some doors will need work. Some windows might look out of level.

Just my personal opinion: do it right and save yourself the agony of a long hard project.