Do Houses "Settle" or do Houses "Sink"? (floor, how much)

[KevK]

This is the situation- house is 14 years old. About 8 years ago it "settled" and caused the plaster to crack in a few places and the doors to appear wider at one end than the other- but they still closed. Now the plaster cracked again where it had been patched before and the closet doors no longer close right. Also the foundation is cracked along where it sits on the concrete slab of the house on one side.
Is this house sinking? Will it stop on its own or will intervention be required? How much would a repair like this cost and can a slab be repaired (2000 sq ft house, 1000 sq ft each floor x 2)?

[jhlcomp]

More information is needed - type of construction - what are the soil conditions in your area, etc. Having said this, and given your experience, I highly recommend getting a structural engineer or some other expert to look at your problem, because your house is no longer settling it is sinking. Good luck to you.

[desertsun41]

Originally Posted by KevK

This is the situation- house is 14 years old. About 8 years ago it "settled" and caused the plaster to crack in a few places and the doors to appear wider at one end than the other- but they still closed. Now the plaster cracked again where it had been patched before and the closet doors no longer close right. Also the foundation is cracked along where it sits on the concrete slab of the house on one side.
Is this house sinking? Will it stop on its own or will intervention be required? How much would a repair like this cost and can a slab be repaired (2000 sq ft house, 1000 sq ft each floor x 2)?

You have some trouble Kev. First off the foundation does not sit on the slab. The foundation sits on a footing. If you have a slab you probably do not even have a foundation but rather the slab is inside of the 1 or 2 course high foundation or just solid cement. This is hard to explain. Do you have a picture?

If your slab is cracked then you have more of a problem then just settling. Where are you? A cold climate? Your footings should be maybe 3 or 4' deep and 12" thick. Warm climate you might be 12" deep with the foundation. Imagine the stress to cause 12" thick of footing to crack and sink.

Give us a picture.

[Cosmic]

From a general question like that nobody can tell you anything in detail. Are we talking a house with a basement?

Settle and sink are really more like layman terms, sort of means the same thing. You could argue some folks mean that the term settle implies a much longer process, maybe of less degree. Sinking is what a lot of these modern shacks do, the problems show up quick. The amounts of movement are unforegiveable.

So much in is play. First what was the soil like on the site? Some soils can be very problematic, it can be a source of a house sinking, usually happens pretty quick. Very difficult if not impossible to fix after the fact.

Soil prep prior to actual construction is also critical. Exactly how did any excavation take place, was the proper base/gravel layer/or whatever established. This needs to take place in a couple of stages. The best methods also use soil compactation any time soil is disturbed prior to construction.

Next you have to consider what type of footings is used. Can be a major cause for the unstable foundations. Many of these modern houses, the footing designs are a bit of a joke. It would be surprising if a house does not start to have problems. Usually the general excavation is done. Then more digging for the footings. Footings are poured, some backfilling takes place, some prep for the slab/ the drain system is also installed in this process. Again once construction is done with poor footing design / construction very difficult to fix.

Then whatever is used for the foundation walls is done, many modern houses they just use a 2 x 4 to make a keyway to bind / lock the walls into the footings. Then the final prep for the slab, usually nothing is done to key the slab into the footing / wall design. Again how do you fix a mess after the fact.

With the type of modern building as cheap as possible a lot of things can go wrong. Especially if there is no basement and the house is built only on a slab. Some of the contractors get away with some pretty shoddy practices.

Once you build something that is of a poor design / installation it is difficult to fix it. Again it becomes more a talking game. The real solution is rip out the junk and do it right. You just do not want to get into the problem in the first place.

If the soils are poor load bearing, then the footing designs have to be changed or do not build. The more recent houses are a case in point. The settling problems are more just poor practices / installation from many builders. Many far older houses have lil or zero settling over long lives. If done right, no house should have the problems. If you get the problems there are not a lot of solutions in a practical sense. "Repairing" slabs, concrete construction is not something you really want to have to deal with. You are probably screwed in the real World. All solutions are limited and may always be flawed.

Probably not what you want to hear but once you have major construction flaws in something to do with the foundations or load bearing areas, piers, footings, walls, etc you are screwed. The solution is never get into the problem in the first place.

[pepe1]

It is difficult to diagnose the exact problem based on your description...It sounds like settlement may be the source of your problem - could very well be other issues.

Foundation problems can be fixed. Helical piers, hydraulic grout, and other techniques can be used to repair failed foundations. Your first step may be to get a hold of a structural engineer in your area or find a foundation contractor you trust...