Depressing... decisions to be made...

Re-hang your layout from the ceiling joists.

Then your floor can rise and fall without affecting the layout.

That or airbags under the legs.

Adjustable table legs, maybe?

Well...   thankfully my original plans call for the second level of the layout to be hung from the ceiling joists.   That much at least has given me hope.    The adjustable table legs may be the way to go for the lower yard which relies on the floor.   More then anything I'm very disheartened and feeling very defeated.    

You may want to find the area with the most movement and then add threaded pipe  that can be adjusted to level the benchwork. By cutting off the bottom few inches( or what is needed to adapt the pipe and threaded ends) you will be able to independently be able to move each leg up or down as needed. I remember a post recently where someone used pvc pipe for this. 

That is really terrible news. I think I saw pictures you posted recently, and it all looked very nice.  Any idea of the cause?  Has it happened before? 

We just moved from a house with foundation problems. So I know this can be an on going problem.  Our floor was fine, but the walls were bowing in. Not sure yours is structural, but maybe you can get a structural engineer to inspect it. We got one for I think about $175. They may be able to advise you on how bad the problem is and maybe something you can do to prevent further heaving? That might be a start and help you decide what to do next.

If there was some way to prevent further movement, maybe you could do that and try to re-level everything and go from there?  Wish I had a better solution for you, I know the feeling.

OH I am so sorry to hear about that.  Hang in there, the members of this forum are engineering wizards on many levels.  A solution will present itself!!!!

Our house was built in 1892.   The walls and foundation all appear solid.   The basement floor from a previous contractor was ...   skim coated which I know is a basement bad idea.   The skim coat is heaving up from the original floor.   The original floor appears unchanged and stable.   It's this stupid concrete on top that has separated and heaved up.   

That said the original floor does have moisture that seeps through.   Hence I run a dehumidifier which over the past 5 years seems to do the trick at keeping things stable.   Yet this recent super cold we just had made things crack and heave.   We've been in this house for 5 years and this is the first time it has happened.   But ya...   this house was built in 1892.... so 5 years hardly establishes a norm.

You said the original concrete floor is stable and only the second applied layer is the problem. Is it possible to drill, chisel, hammer that first layer out to expose the original floor underneath the layout legs and then extend the legs to the original floor? You can probably eliminate some of the legs by tying the together to other legs.

I concur with this advice and withdraw my previous suggestions for repairs. You do have insurance, don't you? File a claim and solicit an engineer to assess the structure and floor. Don't guess.

Certainly having an engineer check out the house is a good idea.

That written, the homeowner wrote that the original floor was subject to water penetration, and that the original floor seemed fine.
Hopefully his problem was caused by water being trapped between the two layers of floor and freezing, lifting the top layer.

Best Wishes!

or is it hydraulic pressure from the heavy rains recently in the east? Hence the need for a professional assessment rather than a guess.

I suggest you file a claim, get a structural engineer and see what other options

are open to aid you.

Many times, State/Federal assistance is available.

My suspicion is similar to CW's, and my fear is if ignored you may have a larger problem of having the upper basement floor start breaking up.  Dealing with that issue when your layout is even further along will be worse than dealing with things now.  It may be possible to salvage most of your work so that the necessary work can be done, such as by moving out elements and/or temporarily suspending it from the ceiling.

Then again I am not an engineer so what do I know.

The root cause of the heaving is from moisture that froze in between the skim coat layer and the original basement floor.   Only the skim coat is heaved.

I have the good fortune of being married to an Attorney who happens to do large scale building projects (sports stadiums, high rises, apartment buildings etc) and she asked one of her engineer friends over to have a look and confirmed that the foundation is fine and stable and it's just the crap job of the skim coat (which never works apparently).  

As to a solution I am thinking I will combine 2 of the ideas above.  

#1 - hammer/chisel out the skim coat that is under the layout legs.

#2 - install adjustable height feet that Penn-Pacific posted above.

#3 - adjust at will and bring the layout back to normal

After getting ride of the crap skim coat under the legs of the layout things should remain stable indefinitely.  

I hate to hear this news.  At least it did not roll several brass engines off of the layout and wreck them, although it's certainly a bad deal as-is.  It's got you stuck between a rock and a hard place, because, eventually, it will have to be repaired before you sell the house, even if that's decades in the future.  You're one of the good guys, and this is a bad break.

Maybe it was a blessing that we were unable to find a suitable home with a basement when we moved to Amarillo.  Despite our being at the south end of tornado alley, they just do not build many basements here.  I passed up an opportunity to buy a big house with a full basement, built in 1940, because of the possibility that it would always need some repair or other.

I had no idea that basement floors could heave, but I guess that, no matter what part of the country you live in, some kind of misery can occur with your house.  Our foundation has sunk and is going to require leveling, as walls are cracking and two doors won't close.  The estimate is $8,000, but, from what you wrote, your problem could be somewhat more expensive.  Trevize, I really hope you can find a solution to this and figure out how to budget it into the long-term financial picture.  (And my fingers are crossed for your insurance to cover some of it.)

Hey..... let me add an idea to that of Penn Pacific.......and save you some time.  Do plan on adding adjustable table legs, but instead of sawing off the old legs....merely add a "temporary" leg to the existing leg using removeable screws.  Make the new leg long enough to meet the floor; add the adjustable extension - lengthen it to touch basement floor.  Then unscrew new temporary leg and continue on to next old leg and fix as aforementioned.  I wish I was there to help ya...........git 'er done!

Sounds like you have a really good solution to the problem. Glad you had an engineer look at it and were able to come up with a solution. Also great that your basement walls are sound. That should give you some added peace of mind, would me anyway. The adjustable feet posted above looked very nice, nice wide foot pads with rubber feet.  

Wish we would have gotten the engineer first in our old house before trusting a contractor and spending money on repairs that didn't hold up. Had to do it before selling anyway. 

Good luck with the fixes and hope you are back to a nice flat rail yard soon.

If you haven't already, get a structural engineer to inspect your foundation before trusting a contractor to do any repairs. Make sure he will re-inspect after the work is complete and approve the repairs. Make the repair contractor do the repairs to the engineer's specs and don't pay them until the engineer is satisfied. You may be more well versed at this kind of thing, but we learned this one the hard way!

We were able to sell our house as is, by just providing a structural engineer's report and estimates of repair costs. This was deducted from the selling price of course, but at least we didn't have to mess with foundation repairs a second time.

Travise;

On top of your plan I'd add one thing.

Install a dehumidifier to deal with the seepage you will get from the exposed old floor.

For the adjustable legs I do this:

Drill a hole straight in the bottom end of the leg several inches deep.

Insert a Carriage nut (name?) into said hole and secure in place. (Nut w flanges to stop rotation by sinking into the wood, some have a screw hole in a flange)

Run a bolt into the nut about half it's length.

Turning the bolt in and out allows height adjustment of several inches.

The head of the bolt is against the floor.

California licensed structural engineer chiming in.  As your engineer friend confirmed, it's a non-structural issue.  A cracked basement slab of a house of that vintage is absolutely normal.  Unless the slab was poured much more recently, by a contractor you hired, you're out of luck with the slab.  If it's an original, or even fairly old slab, it doesn't have a moisture barrier under it, and that's why the moisture seepage is occurring.  Again, the engineer friend is correct, a non-structural topping (skim) coat isn't going to help much.

But sealing off your basement slab isn't a bad idea, unless you want to continually deal with the slab seepage.  You could look into other products that perform better than a skim coat.  Something like an epoxy coating perhaps?  Also if there are big cracks in the slab (found after removing the current skim coat), you could epoxy inject those cracks to get deeper sealing.

Not an engineer, but have a basement with water problems (have a french drain system because of it), and as far as I know the reason water seeps up through the original slab is because of osmotic pressure from ground water. Even if you don't get serious water  (we lost power during one of the nasty storms over the last few years, and my basement ended up with about 4" of water, not a worry any more, have a generator for the pump) there can be enough to cause water to seep up through the slab. Sealing it with epoxy paint or drylok floor paint could help, the only real way is to relieve the pressure. The engineer you had look at the floor probably could tell you more, but one thing to think about is look around the foundations of your house. Are the downspouts led away from the house? Is the dirt sloped away from the foundation? By doing things like that, you can reduce the amount of water seeping down that comes up through the slab. A french drain system call alleviate that osmotic pressure, but it is pretty expensive and probably would require taking down your layout if it is anywhere near the walls, or if the basement is finished taking down walls and such..given how little water you are getting, prob not worth it, easier simply to try and reduce the amount and try sealing the original floor if you decide to get rid of the skim coat.

Ya the original slab is original to the house.   I've now taken up 90% of the 1/4 inch skim coat on top and have all of the original slab cleaned off.   Not a fun task crawling under the layout to perform.

There are no cracks or heaving at all in the original slab.  At first glance the floor appears dry.  But if you put a paper towel on it and stand on it for 10 minutes the towel will come back dampish.   I already have 2 dehumidifiers running; one at each end of the basement and they both have water ejector pumps so I don't have to worry about emptying a reservoir.   Humidity stays at a stable 45% year round.  We also already have a french drain system and we live on top of a big hill.   I don't have any moisture at all coming in through the walls.  The most damp places are actually in the middle of the basement floor.

So ya there isn't a moisture barrier in this 100+ year old slab of course so this would be normal.  The weather pattern that spurred this was a heavy 2 foot snow followed by on the next day a heavy rain and 50 degree temps then after all that water soaked in the temp dropped to the single digits.  Crazy.... 

Today I purchased a bunch of adjustable leg thingy's like the ones posted above for my existing legs.  For all new legs I'll drill a hole and use the cheaper ones like Russell is talking about.    This will allow the wood legs to stand off the original slab and not act as a sponge for the moisture that does seep in.

Sounds like things are looking up for you. That's much better from your original post. Glad things are going your way. 

Those leg levelers are really nice. The one's Russell was talking about are T-Nuts. I just built some workbenches using those in 5/16" size. I found some rubber padded feet (foot was about 1" dia. on a swivel) at our local Woodcraft supply store. The benches were quite sturdy with those feet.  Might be better than just a metal bolt head for not trying to slide around?  Probably could find them cheaper online somewhere.

I am glad it was the skim coat and not the original concrete, that is a relief! I would recommend once you finish cleaning off the old skim coat, to think about painting the floor with an epoxy paint (Home Depot has it) or if you don't want to go the epoxy route dry lok has a floor paint that can help seal concrete slabs. I am surprised with a french drain system and being up on a hill that you are getting water like that, but I suspect with that kind of setup if you seal the floor you won't get much if any seepage. Plus a painted floor will look a lot better I think

Trevise,

Good to hear it was only the skim coat. I am curious though, how deep is the foundation bottom/basement floor below ground level? That was a lot of work to clear that out! Wet\Damp basements are a pain.

The Mass. code requires 48" on new construction and the NAVFAC specifies 50". Being on a hill would require a greater depth to stay below the frost line using a depth based upon local experience.

Secondly, being on a hill doesn't necessarily mean that you are above the water table. Since the original floor remains damp it would appear that the water table is up against it most of the year.

The stupid weather, as I call it, dumped a lot of rain in Nov and Dec followed by the snow that melted and created a higher water table (hydraulic pressure) forcing the water through and under the skim coat. Your basement floor, most likely above the frost line, caused the water to freeze and create ice lens to heave the skim coat with strong pressure. So, your conclusions are most likely correct.

Sounds like you are approaching this situation the best way and dealing with the symptoms. You won't win trying fight the existing soil and water conditions. Like they say, "it is what is". You could build a new basement and foundation for the cost of trying to change this one and it still may push water.

T-nuts and galvanized carriage bolts should work great for the other legs. Good luck to you and keep and eye on the tops of the foundation walls\ sill plate area for any changes after weather events like this past experience.

Note: attached is a Mass. code excerpt and a NAVFAC 7.01 excerpt