Manhole turned up in Foundations - see pics.

[ColJack]

presumably this thing has it's own foundation ( it's brick after all ), so wont they just accept a lintel / cap on top of it resting on the brickwork?
as you say it's not exactly load bearing is it?

 

[noseall]

What you all need to think about is the size of the excavation needed in order to build such a deep structure. There will be a large area of back fill i.e. disturbed ground around the manhole that also needs accounting for.

You need to bite the bullet and reach for the cheque book.

 

[Nige F]

We found it was part of the old sewerage system for the old street of houses that used to be on the site. I wouldn't mind but this will only be a single storey extension, and this part is right under where the french windows will go, !

Start worrying when you find those old french Letters @ the bottom

 

[mnb]

1. It wasn't clear at all to me what the "resolution" was?

2. The approx. depth of the trench seems to be six feet - how come BCO didn't mention shoring up the trench? Beware, trench collapse is sudden and deadly.

3. Any further digging out will require shoring and strutting and expert opinion regarding nearby structures ( including free-standing walls). Noseall has already indicated further possible difficulties.

4. Do you have a ground map of where the utilities are? And similar for main drain?

5. If your "resolution" turns into a dockyard job, then you should have a realistic total cost estimate and a cool think, "is it worth it"? Then again, perhaps i'm being pessimistic.

 

[lj329]

ok, the resolution is to dig down to just below the foundations of the manhole to a width of 1 metre either side to create "pads". This should mean there is a secure base either side in undisturbed ground. Then once filled use concrete lintels to stop any significant weight on the old structure.

We have dug out the sides of the foundations down to about 2m - the guys didn't shore up as they said the ground was firm enough not to warrant it.

I reckon this will add another £800 to £1000 to the bill

Untitled

• lj329
• 6 Jun 2010
• 1

Untitled

• lj329
• 6 Jun 2010
• 1

 

[Nige F]

ok, - the guys didn't shore up as they said the ground was firm enough not to warrant it.





]

What are they , Gravediggers ?

 

[noseall]

The approx. depth of the trench seems to be six feet - how come BCO didn't mention shoring up the trench? Beware, trench collapse is sudden and deadly.

Since when has it been within building control remit to issue h & s advice or tell a builder how to do his job?

However you are right to be concerned about the depth of the trench, so good advice........
click me
......

 

[lj329]

Jeez, and I thought I had to dig a deep hole!

 

[Hugh Jaleak]

Deep is when you have an 18 tonne machine digging a trench to sit itself in so it can then get to the correct depth at full stretch....

IIRC the drain invert was about 6.5m on that job, and needless to say we had a box for trench support.