Extenstion on underpinned property

[biggiebig]

Hi I’m in the process of buying a 1930's 3 bed semi with an attached garage. Partial underpinning was done at the back of the garage & near the kitchen in 1992.

I am planning to build an office behind the garage to the side of the kitchen. And in the very very distant future may build above the garage and a single storey rear extension.

Also the house next door (the house unattched side) closest to the garage was underpinned details are as:-

Underpinned in 1992 - i.e Same time
Underpinned again 1994 - prior to extension
extension built in 1994
underpinned again in 1998
rear extension underpinned in 2000

so the house next door has been underpinned 4 times. Twice after the extension.

Would the house that i'm purchasing have any consequences with any extensions I plan due to the fact it has been underpinned? i.e. Increased weight on the house !!!

 

[noseall]

alarm bells

the word "underpinning" strikes the fear of god into me!

is the house in a mining area?

do you have to buy this particular house?

what are the reasons for the u.p.?

 

[JerryM]

sometimes you have to bite the bullet and get an expert.

this is one of them. you need to find a structural engineer ideally recommended by word of mouth. you don't need an expensive report just his verbal advice having visited the site.

they are simply invaluable. as noseall correctly identifies without one is quite likely to lead to tears.

with one however is like a breath of fresh air. i would have walked immediately away from many houses with structural problems. with the structural engineer's input you can build the costs into the equation (albeit these costs can be quite high as well as quite low).

also there is a stigma associated with underpinning which may cause difficulty gaining insurance. also if the visual effect can't be sympathetically improved (ie levelling floorboards) then selling on is likely to be a problem.

only for the brave acting with a structural engineer.

in answer to the question of consequences on the extension foundation i believe it would be YES and the attachment (loading) to the existing building would need careful design consideration. the underpinning is because the ground can't support the load. a single extension would be feasible but a i think a double out of the question due to the increased cost of the foundation required.