Reassure me - foundations of old lean to extension

[Cellophaneskies]

Hi.

My house is mid 60s. It’s had a lean to extension installed at some point in the past. It’s single storey, flat roof, roughly 3x3m. My neighbours tell me it has been around since at least the mid 80s, so it has been standing for a long time.

It’s all square and true outside, but weirdly the bottom half has been rendered, and that is very wobbly - some of the render depth is shallower than the brick above it so I suspect that’s hiding something.

I was wondering how secure and stable this extension is. On both sides, one spot on each, I have dug into the earth and I can actually dig under the wall in that spot! As if it has no foundations and is sat on the earth at normal ground level.

Now this seems weird to me. Surely if that was the case, it would have sunk by now, over the course of fifty years, if the foundations weren’t solid.

Is there some non-usual construction technique that may be supporting this? Perhaps a metal frame supported at corners or something similar?

obviously without knocking it down or digging it out it’s hard to tell, but i thought I’d ask here in case this sounds normal or indicative or some sort of unusual construction type.

Thanks!

 

[tony1851]

You need to post a few pics - hard to understand what's going on.

 

[Ivor Windybottom]

Dig out alongside it. If this is enough to make it fall down then you've answered your own question!

It should sit on concrete, which should sit on clay, sand or rock - not black topsoil.

As it's only 9sqm then if it's substandard you could either not care about it or replace it. It's very unlikely to make sense to try and fix it. It's very expensive to build downwards under something. If they didn't bother with foundations then you can guarantee there will be many other issues too.