We have recently bought an old mid terraced house, early 1900s build, in the Salford, Manchester (NW England) area.

We have two cracks as follows:

Front upstairs bedroom: The crack runs diagonally downwards in the alcove wall which adjoins onto next door, from the top of the chimney breast to approximately a third way up the wall into the corner where it adjoins to the front elevation of the property wall.

There does not seem to be a crack downstairs in the front living room to match or line up with the crack.

Front living room: there is a vertical crack in the corner of the front elevation wall with the hallway wall.

Do you have any ideas on what the cause of both cracks may be and what the remedy is?

  • 5
    Photos and sketches will be helpful. Describing the cracks with reference to visual landmarks within the room is not helpful to us, since we can't see your room or the cracks.
    – Tester101
    Commented Jun 6, 2014 at 15:51
  • 1
    As Tester101 says, it's hard to say without photos or an indication of the size of the crack. The upstairs crack could just be a bit of movement in the roof, it's not uncommon, but hard to say from your description alone.
    – John
    Commented Jun 6, 2014 at 19:04
  • 1
    Besides photos, also tell us what might not be seen in photos, such as the wall material and underlying structure, if it's a bearing wall, etc.
    – bcworkz
    Commented Jun 7, 2014 at 17:36

1 Answer 1


(Caveat: I'm a DIY type, not an expert.)

Diagonal cracks in old houses are usually the result of settling. Houses start out square, but they shift over time -- and turning a square into a parallelogram means stretching one diagonal and squashing the other. I've got some of these in my house, slightly older than yours -- most were patched and repainted before I bought the place but are still visible if you look carefully, a few were probably caused when I had a loadbearing wall replaced with a parallam beam.

If the cracks are new, and you haven't done anything like I did which might cause stresses to be redistributed, you should consider getting the place inspected by a contractor and/or engineer to make sure it isn't currently moving. You may need to install lally columns in the basement, or do some foundation work, to properly support the house so it stops moving.

Or it may be something more serious, but that's why you want the experts to look at it. (Neighbors had to demolish the old farmhouse they were hoping to rescue, when they discovered that it was both off the foundation AND had a broken main roof beam. Either would have been repairable by itself, but no reputable contractor would touch that combination.)

As far as repairing them: Once you're sure that the shifting which caused them isn't still in progress, it's like any other plaster repair. For small cracks, apply patching plaster, sand, repeat if necessary until the wall is smooth and level, and repaint. For larger cracks, you may need to use mesh tape to help support the patching plaster while it hardens. It may be desirable to undercut the crack slightly, to help ensure that the new plaster gets a good grip on the old.

If the house is going to continue to move, you're probably going to have to repair the crack repeatedly. Some folks suggest, in that case, using a paintable elastic caulk in place of the patching plaster; I'm skeptical.

  • +1 Make that crack into a fill-able gap with a 5in1. Use mesh tape and durabond, a setting-type compound (the stuff in the brown bag that's really hard to sand) to set the tape. Top it with the easy stuff.
    – Mazura
    Commented Oct 6, 2014 at 9:16

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