Subsidence - Infilled Land [FTB]

in_w4ves

Hi everyone, 

FTB here so looking for some advice please. How serious is subsidence caused by infilled land? 

I'm almost 2 months in to a GF flat purchase and the searches just came back last week. 

The property is a new build from 2013, I am hoping underpinning would had been done at time of built (but no specific mention on NHBC guarantee) and if any sign of progressing subsidence there would be cracks to indicate as such from past 7 years (none reported in the HomeBuyer survey). I've also tried looking on local authority's planning application but not any more enlightened!

Any other suggestions on where I can look and how to proceed? Or is this a big no-no? 

AdrianC

That recent a development, the ground will have been appropriately managed prior to construction - and it's old enough that cracks would be evident if it had been inadequate.

davidmcn

in_w4ves said:

I've also tried looking on local authority's planning application but not any more enlightened!

Can you explain why not? For something this recent I'd expect the planning papers to include site investigation reports i.e. tests done by the developer involving drilling holes etc to see what the ground conditions actually are, so they can take account of them in designing the foundations etc - not just finding something scary-looking on an old map, which is basically what you've got.

Doozergirl

davidmcn said:

in_w4ves said:

I've also tried looking on local authority's planning application but not any more enlightened!

Can you explain why not? For something this recent I'd expect the planning papers to include site investigation reports i.e. tests done by the developer involving drilling holes etc to see what the ground conditions actually are, so they can take account of them in designing the foundations etc - not just finding something scary-looking on an old map, which is basically what you've got.

That would be Building Control.  Planning is more to do with the concept of development being suitable rather than the ability to actually build it.  

davidmcn

Doozergirl said:

davidmcn said:

in_w4ves said:

I've also tried looking on local authority's planning application but not any more enlightened!

Can you explain why not? For something this recent I'd expect the planning papers to include site investigation reports i.e. tests done by the developer involving drilling holes etc to see what the ground conditions actually are, so they can take account of them in designing the foundations etc - not just finding something scary-looking on an old map, which is basically what you've got.

That would be Building Control.  Planning is more to do with the concept of development being suitable rather than the ability to actually build it.  

But being suitable does include things like whether the land is contaminated, or if the residents' amenity will be adversely affected by their house disappearing down a mineshaft...which is why site investigation reports are invariably among the planning papers.

weeg

The foundations for the flats will have been designed to suit the infilled ground. NHBC don't guarantee anything they think they might actually have to pay out on. Underpinning wouldn't be mentioned on the building standards details, because underpinning is a remedial repair. It'll just have been built so as to avoid needing underpinning in the future.

in_w4ves

davidmcn said:

in_w4ves said:

I've also tried looking on local authority's planning application but not any more enlightened!

Can you explain why not? For something this recent I'd expect the planning papers to include site investigation reports i.e. tests done by the developer involving drilling holes etc to see what the ground conditions actually are, so they can take account of them in designing the foundations etc - not just finding something scary-looking on an old map, which is basically what you've got.

Hi david,

I could only see elevation, site plans, testing of chemicals.. nothing on structural bar the Developer submitted a planning permission to offset 1 area and reason given engineer advised. But nothing more..

in_w4ves

Doozergirl said:

davidmcn said:

in_w4ves said:

I've also tried looking on local authority's planning application but not any more enlightened!

Can you explain why not? For something this recent I'd expect the planning papers to include site investigation reports i.e. tests done by the developer involving drilling holes etc to see what the ground conditions actually are, so they can take account of them in designing the foundations etc - not just finding something scary-looking on an old map, which is basically what you've got.

That would be Building Control.  Planning is more to do with the concept of development being suitable rather than the ability to actually build it.  

Does a building control have paper trail I can try and dig around for? 

ProDave

Underpinning is a remedial operation to an existing building.

It is more likely the foundations would have been built on piles that will have been driven down through the infill to reach solid ground.  Building control and NHBC will have inspected and aproved the foundations at the time.  Nothing to worry about.

If it were a house you were buying, then it might be a concern because if you wanted to extend it in the future, you would have to do similar which would make the extension more expensive, but you are unlikely to be wanting to extend a flat.

in_w4ves

ProDave said:

Underpinning is a remedial operation to an existing building.

It is more likely the foundations would have been built on piles that will have been driven down through the infill to reach solid ground.  Building control and NHBC will have inspected and aproved the foundations at the time.  Nothing to worry about.

If it were a house you were buying, then it might be a concern because if you wanted to extend it in the future, you would have to do similar which would make the extension more expensive, but you are unlikely to be wanting to extend a flat.

Thank you...that’s really clear and helpful. 

I’m feeling totally out of my depth with buying alone and no connection with knowledge or experience on it. Much appreciate the guidance