Sagging Floors

thanks all.
And yes, mopar I did ask this question a few days ago.
And still trying to figure out options and possible cost before signing a contract and going forward.

I will have to be content with whatever inspection reveals.

If the floors are sagging, 99% of the time either the foundation or the joists are the problem. Hopefully it’s the joists, foundation issues are much more problematic, especially since most housing in NYC is attached to buildings on either side which makes remediation much more difficult. Sagging, or a bow in the middle usually indicates joists. Drastic sloping to one side or the other could be foundation, although it’s my experience that most older houses tend to slope towards the staircases. If it’s a foundation issue, you’re going to need real professionals to deal with it, not your average run of the mill GC and definitely not something to take on yourself. And yes, it is ridiculously expensive. Sagging in floors is easier to deal with, but still a pain in the butt.
The easiest fix to sagging floors is to install what they call sleepers on the floor which are basically wooden strips all shimmed to the same level which you then apply new flooring to. The problem with this is that usually floors sag because the joists are either undersized for the load that they are carrying, spaced too far apart, or both. By using sleepers, you’re just compounding the issue, adding even more weight. So while it’s a quick fix, it’s not going to be a permanent fix. I’d avoid doing this, or any GC who recommends it.
That brings you to option two which involves removing either the floor, or the ceiling underneath, depending on what you would rather have evened out. It’s difficult to get both leveled because in order to do that, you would have to remove the ceiling, jack up the joists in the middle to take out the bow, or “banana” shape and replace the ceiling. Most older Brooklyn houses that I’ve run into have a hybrid mix of balloon framing and timber framing, which means that the joists aren’t really that secure on the ends, so when you go to jack them up, rather than take out the bow, you just push everything up. So what most people do is live with a sagging ceiling, but take the sag out of the floor. This is done by removing the flooring and “sistering” a new beam onto the old beam. Basically all sistering is, is bolting a new, straight beam onto the old beam. It’s fairly straight forward if you plan in advance, but it is very labor intensive. Things that make it more difficult are pipes or electrical wire running through the beams, fireplaces and stairwells which are going to have headers that may be undersized, but most importantly, you have to look at the room as a whole and see what the consequences of leveling the floor are going to be. First you have to determine if you want to get rid of the sag, or actually level the room. Find a level point throughout the area that you are dealing with. You might find a significant difference. Assume you have a fairly common brownstone layout and the stairs and doors into rooms are on the same side, if that is where the building slopes towards, you have to determine if by leveling the floors will you be creating a situation where your doors have to be cut down, and the first step is going to be significantly deeper than the rest. If this is the case, you might want to either just use the two side walls as the apex of the new joist, whether it is level or not. Another option to consider is taking out the sag only in one area, where you use the demising wall, or exterior wall, and an interior wall as the end point of the new beams and don’t worry if the rest is out of whack. Not an ideal situation, but a lot easier. If this scenario, you may have no sag in the main room, but a little sag in the hallway. You’re going to want to end the beams on load bearing walls though, or you’re just going to have more sagging in the future. This post is getting very long winded, so I’ll wrap it up, but keep the following in mind, and if you’re using a contractor, make sure he or she addresses these issues;
-How deep are the sistering beams going to be (the deeper the better for strength. unfortunately the contractor really won’t know for sure until they open up the floor, but stress that you want as deep as possible. If the contractor is saying 2×4’s, you’re not really gaining much strength and he’s pushing a quick, probably temporary fix and is someone you might want to deal with.
-How are they going to deal with pipes and wires? Are they going to notch the beams or reroute the wires/pipes? Notching will destroy the integrity of the beam, but it’s a lot easier, so most people are going to try and cut corners by taking this option.
-Don’t assume that there aren’t going to be any pipes, a lot of old brownstones had gas lighting in every room and the pipes will still be there, many times they are active, so you can’t just cut them out.
-Are you leveling the floor, or just getting rid of the sag? If you’re leveling, how is that going to affect doors, stairs, plumbing and electrical outlets. A lot of older houses only have one layer of flooring, which you’re probably going to remove and replace with a layer of plywood. What are you going to put on top of the plywood and how are you going to handle the transition from the old floor to the new, which will now be on different levels?
-How are they going to attach the plywood? Screwed and glued is best, but again, a pain to do.
-Specify bolting the beams. This is code, but one of those codes that gets broken often, but shouldn’t be.
-I would recomend not