Footings on extension

[mayzes7]

Hi
We have recently moved into our house - it has an extension which was built 1970ish and is 14'5" x 21' the rear wall of the extension has glass doors right across but we want to replace these doors with two patio doors and a brick wall. But it would seem that the foundations on the whole extension are only 9" deep - I am waiting to get a copy of the plans but I am wondering if these footings are right - if I was to build this now I would need a metre deep on the footings. Can someone let me know if the bulding regulations would have allowed this in the 1970

 

[tkmax]

Unless the extension is built straight onto rock then its unlikely to have complied back then (although tbh I'm too young to remember). However, if the foundations haven't failed in 30 years then they could be considered fit for purpose regardless. It could also be built on a raft foundation, or piles and ground beams, either of which would appear similar from an external trial hole.

 

[jeds]

How do you know it had building regs? Even the worst cowboys usually go a bit deeper than 9 inches. My guess is a raft or summat. But you'll have to send a small boy under the house to check.