Cracks in gable end of house

[kelf1]

Hi,
I am currently looking to purchase a semi detached house about 50m from a beach. The house is built primarily on sand or very sandy soil and is around 100 years old. The house is pebble dashed (as are most on the street) and the pebble dash appears to either be original or long standing pebble dash. There is cracking in the gable wall outside the kitchen window where the drain (soil and kitchen) enter the ground. The cracking runs from the floor to the ground floor kitchen window and then from the lintel of the kitchen window to the first floor (bathroom) window. There are a 4 or 5 cracks in total. I have had a structural survey carried out and the surveyor says it is probably due to a leaking drain that has washed away the sand/soil and is ongoing but cannot be certain that it is a leaking drain without excavating and knocking off the pebble dash render to see the extent of the cracking. He also says that if it is a leaking drain and it is repaired then it is likely that it will not get any worse and will not require underpinning.

Does anybody have any experience with something similar and would be willing to share their knowledge and experience? I am most concerned about the requirement to underpin due to the cost and prospects of a sale in the future.

Also, if the soil/sand has been washed away by the drain wont the 'gap' require filling in one way or another?

I am most grateful for any input and thank you in advance.

I have lots of experience as a homeowner of a house with moderately serious cracking
I would honestly say, unless the house is amazing / a one off and you have plenty of money / time to get it sorted (not buying as an investment or to sell on in five years), don't go ahead with the purchase.
It's a total headache getting structural issues sorted and there will always be the potential for the cracks to return.
Your surveyor describes the problem as "a leaking drain that has washed away the sand/soil and is ongoing" - well, the word for that is subsidence. So you'll have to go through the insurance company and your card will be marked for ever after. They don't tend to underpin now unless they have to - usually the house will stabilise once the cause of the subsidence has been addressed. But it's still subsidence and once a property has that history, it will be expensive to insure and quite possibly difficult to sell.

Some of the above isn’t accurate. The vendors should claim in their insurance if it is indeed subsidence.

Once a house has been underpinned it is a much better proposition than one that hasn’t been and insurance for an underpinned house really isn’t an issue.

If you are not that keen on this house, walk away. If you want it, the vendor must sort out this issue. Don’t take it on. Also get a Structural Engineer to look at it. Their report will be more detailed than the surveyor. If the vendors are not interested in sorting it, on their insurance. do not buy it.

An Underpinned house doesn’t usually get a recurrence. The reason why underpinning doesn’t happen is that insurers don’t want to pay for it. A good Structural Engineer will fight that corner for you. Houses don’t right themselves with subsidence. It’s simply insurance companies not paying up and spinning a yarn!

There's a strong argument for not underpinning a house that is part of a semi (unless the other half of the semi is underpinned at the same time); equally a partial underpinning of a detached property is to be avoided as the underpinned part of the structure will stop moving and the non-underpinned part may still shift, causing even more cracks.
Same PP saying If the vendors are not interested in sorting it, on their insurance, do not buy it - this is right and fair enough, but it could easily take 2-3 years before the claim is complete and the house deemed sound.
So in essence, get a proper structural engineer to look at it which will cost c£1k. If it is subsidence, sadly I think you have no choice but to walk away.