Cracks in Extension

[Yozakaka]

Hi there,

Our bungalow is 1950s with living room extension of around 4m x 4m in early 90's. We moved here 2001. Last year we saw some cracks in the pointing and through a couple of bricks underneath the exterior window of the extension and in render above window. We contacted the insurers and a surveyor bored into the ground. He found old dead roots and clay but wasn't worried and told us to make good and keep an eye on it. We made good(ish) earlier this year by replacing the bricks but I noticed a couple of weeks ago that the crack in render has appeared again - although only hairline, I guess this means something is moving...
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To make matters worse, I noticed today that the lining paper was splitting in the corner of the room and pulled it off to see a plaster crack from ceiling to floor (max 2mm) where extension meets original building. It looks messy at the top.

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We're thinking about moving house but panicking now that we might have a problem. Wouldn't want to sell to anybody if I knew something was wrong... but don't want to lose tens of thousands if we put in some kind of insurance claim.

Do you think this looks serious ? Any advice would be gratefully received.

 

[^woody^]

They look normal to me, and the internal plaster ones looks very old.

Common shrinkage or typical movement of a new building to existing

 

[Yozakaka]

Thanks woody. Was worried something nasty was happening. Wife was going to call a SE to take a look (got to stop watching those Sarah Beeny programmes), but perhaps might just be better off filling for now. There is another vertical crack central above the radiator in the extension but I'm 90% sure that one is just thermal.

 

[xdave]

I am not a structural engineer, so I can't comment on that aspect of it, however...

When I removed some wallpaper to redecorate my bedroom about 10 years ago I found a crack that looked almost exactly the same as yours, except it was about 30mm across at the top, three feet deep, and went into the ajoining bedroom. At least I found out why I could hear the other room so clearly! Turned out that the internal dividing wall was not stitched to the internal blockwork skin and when the usual settlement happened as with any building the walls settled at different rates and cracked. After stripping off all the wallpaper the state of the bare walls was such that I thought the Normandy landings may have taken place on them, with cracks and filler everywhere. The wall was made good, the cracks repaired (and some ties added to the partition wall) and the room reskimmed. This last weekend I stripped the walls bare again to redocrate and not a crack in site.

Your photos all show the typical movement cracks I've seen in every house I have ever lived in. If the house has stood for 60 years then it will be pretty settled by now, however a 15-20 year old extension can still be moving a little. As Woody points out - cracks along building joints are pretty common. I would repair and keep an eye on it until you sell, but unless the movement is still happening I would not mention it when selling (nor would I expect to be told as a buyer).

 

[Yozakaka]

Many thanks for your help. Good to know that it's nothing unusual. Will make good and monitor!