Hairline cracks in extension


23 Oct 2006
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United Kingdom
We moved into our current house in 2005 and in 1998 it had had an extension built. The extension included a conservatory, extended kitchen and a new bedroom built on top of an existing garage. Now there are no problems in anywhere but the extra bedroom.

Ever since we moved in there have been cracks on the bedroom ceiling and under the window, but since they hadn't been getting any worse we assumed it was just a result of settlement. However, today I have noticed a few more hairline cracks on the wall that I am fairly certain weren't there before.

There is a crack from the window to floor, the join between the extension ceiling and the old exterior wall of the house is cracked all the way along and the opposite wall now has a hairline crack running from ceiling to waist height which also runs very close to a crack that runs all the way accross the ceiling.

Should I be worried about these cracks or is it just a result of the weather?
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The below-window and ceiling cracks are just due to shrinkage. If the others are only hairline, I wouldn't be concerned, certainly at this stage.

If you're intending to decorate, then repair the cracks, which will effectively enable the building to self-monitor. If they reopen to any signifcant degree, then think about investigating the cause further. By significant, I mean going to 1mm+ size through the repair.
Is this construction plasterboard lined or normal plaster?

Either way, once plaster has cracked it will most likely crack again in the same place if it is just filled with some token filler.

When the weather changes winter/spring and autumn/winter are the common times for internal shrinkage cracks. So you can get cracks irrespective of how old the property is

I would add to the old guys comments above is that if they open and continue to open, then investigate further
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I think the walls are normal plaster and I am pretty sure that the ceiling is plasterboard.
Shrinkage. Don't have any sleepless nights over hairline cracks.

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