Scary Foundation Excavation.

[tony1851]

For those of you who may be interested in foundation trenches, have a look at this.
Ground is soft sand; hopefully it wont rain tonight.

Untitled

• tony1851
• 31 Oct 2012
• 1

Untitled

• tony1851
• 31 Oct 2012
• 1

 

[catlad]

Scary! what was there response when you questioned them about it. Woody posted one similar that slipped into the trench in Birmingham about 6 months ago if I remember right.

 

[tony1851]

Scary! what was there response when you questioned them about it.

He was totally unconcerned and said, quote; "we'll bi mass-fillin' i' in a coupla days".

 

[noseall]

Unbelievable!

We did one this time last year whereby we had to concrete in stages due to proximity to the neighbouring building.

In my home town a few years back the side of an end terrace collapsed due to this exact same scenario.

Trés scary.

 

[dhutch]

What im missing is, whats the trench actually for?

 

[simonjay]

Unbelievable!

We did one this time last year whereby we had to concrete in stages due to proximity to the neighbouring building.

In my home town a few years back the side of an end terrace collapsed due to this exact same scenario.

Trés scary.

I did a trench a bit like that running alongside neighbour's kitchen / coalhouse outrigger (skeleton party wall agreement signed, no surveyors). Next door foundation about 400mm, my trench 1000mm.
My risk analysis allowed me to do it, bearing in mind:
- it was only single storey
- it didn't undermine quite that much (!)
- There were several buttressing walls I knew about (on the wrong side !)
- I left a few inches that I sliced out the day before the pour
- I hosed down the clay to keep it damp while it was exposed

In solid clay you can get away with it. Not in crumbly soil !
There is a build near to me where there are houses on two levels that were divided by a big retaining wall. They are building on the low ground and have removed the retaining wall and dug into the high ground leaving a "cliff" about 4 metres high, just feet away from the high lying garden fences. It does not look safe to me, but has been like that for a few months.

 

[RonnyRaygun]

In my home town a few years back the side of an end terrace collapsed due to this exact same scenario.

Trés scary.

There was an episode of Homes From Hell where the same thing happened. The couple lost their house and were bankrupted because the insurance didn't cover such incidences, and to top it all the girl was likely to be struck off as an accountant as qualified accountants are not allowed to go bankrupt!

 

[tony1851]

What im missing is, whats the trench actually for?

In fact,the wall perched above the trench is to be demolished, and that part of the building is to be widened by just 18", hence the proximity of the foundation trench.
However, men were (are!) stripping it out inside and upstairs; I'm just hoping they can mass-fill it tomorrow as scheduled.....

 

[noseall]

We dug along side a wall in some ridiculously friable soil. It was old river bed, almost like egg timer sand only coarser.

The wall in question was only 2.1m high and 1.8m long (existing garage) and we wanted to see how the wall and soil beneath reacted as we dug away.

Once the trench reached aboot a metre in length the walls of the trench (if you can call them walls) started to give then in about a second the lot was in a heap in the trench.

Scary fast.

 

[tony1851]

Once the trench reached aboot a metre in length the walls of the trench (if you can call them walls) started to give then in about a second the lot was in a heap in the trench.

Scary fast.

Now, you've really spoiled my evening!

 

[noseall]

They were very unusual soil conditions but typical of the region.

Great Bridgeford in Staffs.

 

[tony1851]

They were very unusual soil conditions but typical of the region.

.

thank goodness for that!!

 

[masona]

Unbelievable!

We did one this time last year whereby we had to concrete in stages due to proximity to the neighbouring building.

Same with my extension, the BCO would only let me do 1.5m concrete footing plus metal rods as I went to 150mm from my neighbour footing