crack in exterior wall

[Misty9]

We've been in our 1930s semi for a year and when we got the building survey done we enquired about the large horizontal cracks to the bay; we were told they weren't a serious issue.

We've had the front bedroom redecorated this week and our decorator reckons these cracks are the cause of the damp walls - its taken three days for filler to dry and there are signs of historic damp.

Is he right? Would rain get into such cracks and saturate the brickwork? If so, what do we do next? Check the roof? It's not lined if that' makes a difference?

Are the cracks in the mortar joints between the courses of bricks or in the bricks themselves?

If they are in the mortar joints then it sounds as if the bay needs repointing. It will then need time to dry out thoroughly. Depending on what the prevailing wind is like, rain could be getting blown at the bay and working its way through the cracks or rainwater could be running down the brickwork because the guttering needs cleaning or fixing and working into the cracks that way.

Were the windows replaced relatively recently do you know? In 30s houses, the frames and sills were built to support the whole bay structure so if this wasn't taken into account when the windows were replaced, then there could be very little actually supporting it all. That could be the cause of the cracks.

With reference to the roof, do you mean the tiles are fixed the the roof timbers with no felt between the tiles and the wood? It's just the way rooves were done then and doesn't mean it will leak. We have the same kind of roof on our house. Is there any evidence of a leak within the loft space? Can you see any roof tiles out of place or flashing missing or out of place if you stand back, across the road for example?

No easy answers, unless there's something obvious then it's a process of elimination.

Wowfudge, that's interesting what you say about 1930s windows being designed so the frame supports the wall above. We have had to put lintels above all our (modern double glazed) windows because it was noticed that there weren't any.

Thanks wow , lots for me to investigate! We replaced the windows about a year ago and they were 20 odd years old, but the cracks pre exist that. I think the cracks are in the mortar, and our decorator said repointing was the solution but a temporary fix was to fill the cracks...

roof is fine as far as we know. In fact we had the porch flashing redone recently and it turned out the roofer had done ours 20 or so years ago! He said it looked fine from the outside. We thought the lack of flashing was causing our damp but the concrete they used to fill between render and flashing has fallen off - decorator reckons this is because the wall is saturated?

I feel a bit like when I take the car to the garage and they could say anything was wrong and I'd have no clue :(

Get all the gutters checked and cleared of any debris and get the bay re-pointed. The damage water can do is immense - not something to prevaricate over.

Get a builder to have a look at it for you. Your decorator may be correct in his assessment, but he is a decorator!