Is my house sinking? (very long-winded!)

Mander

Wow, it's been a long time since I've been on here. This is a very long-winded post, but basically: do the cracks in my walls mean that my house is sinking?

Some background: my house is a semi-detached traditional brick house, two stories, built as a council property in 1959. Like most houses in this area it is built on a slab and the underlying soil has a lot of shale (I believe -- this is in the northeast and there was a lot of pit coal mining activity in the area). I know that soil movement can be a problem in the region but the surveyor found no cause for concern when we bought the house, about 4 years ago.

The previous owner ran into financial problems, and was evicted from the house. Consequently we don't know very much about the history of the house but it is obvious that she had some work done by unscrupulous builders. In particular, all of the original timber framed windows were replaced with newer UPVC, but they failed to put in the rolled steel lintels to support the wall. The worst was where the original external coal store was removed and turned into a back door with a big window next to it. During the repair the bricklayer found that the wall above the back door was actually propped up with bits of particle board wedged between the bricks and the UPVC frame, leaving a 6-foot wide section of the wall with virtually no support at all! For various reasons it has taken a while to get all of the walls repaired but the last one was finally finished last fall.

There are various cracks in the plaster all over the house, mainly on the ceilings, following what appears to be wall studs and floor joists behind the plasterboard. But there are several vertical cracks in the walls above windows or adjacent to internal doors, some of which have appeared since I painted everything 4 years ago. There are also cracks along the joint between the walls and ceiling in most rooms, some of which cross a corner at an angle. Inside a closet on an exterior wall the plaster is cracked in all kinds of crazy directions, almost as if it had been smashed. I'm not really sure if the cracks are getting worse or if I am just becoming more paranoid about them. None of them are particularly wide (they are all 1mm or less), but the sheer number of them concerns me.

So, my actual question is this: does the fact that the walls above the ground floor windows have been unsupported for an unknown period of time (but at least 3-4 years) explain the cracking? The side of the house where it is worst is above the back door, and I believe the wall was actually pushed up an inch or so when the repairs were done, slightly changing the shape of the house. Or does this pattern of cracking suggest that the foundation is moving significantly and I need to get a surveyor in ASAP?

Tucker

No expert but hairline cracks are rarely a cause for serious concern.

Given that you have had work done to rectify previous poor work, then it's common for some cracking to occur, but it should settle down now the work has been put right.

When I did my extension I removed 5m of the rear wall to open up the house in to the new extension. We fitted steels and there was some hairline cracking in the rooms above, mainly around the windows. That's normal as the steels take the load and have some deflection and that has to go somewhere.

If you've had any kind of similar work, which it sounds like you have then personally I would repair and fill the cracks and then observe.

Even though the windows were previously unsupported, by removing them and correcting the work, it's likely to have an affect above.

If you feel it's anymore than that, then for piece of mind, get it looked at proffessionally.