Well in line of footing

[Notch7]

Im doing a job, groundworkers have started to pull the footing.

Right on the front corner of the orangery, they've uncovered a capped off well.

The building inspector is visiting in the morning, I suppose he is going to say 'engineered solution'.

What is a common way to deal with it? Is there going to need to be a pad outside the footing line and a steel spanning? Do I need to fill it in?

 

[^woody^]

Search the forum. There was a post about this exact thing a few years back. Reinforced slab or concrete lintels to bridge it.

 

[noseall]

Fill it with concrete. That'll be some pile foundation!

 

[Paulg31]

I worked on a project where an old mine shaft was found, we designed an reinforced concrete cover slab to span across it.

 

[Notch7]

Many thanks for the advice!

The well head is now exposed it is 1 metre diameter x 16 metres deep. Its got no water in it. Brick built with lime render to the inside face.

The building inspector said he would prefer it if we filled it in with type 2 granular sub base.

Actually that could be the cheapest option. If my maths is correct, I make about 12 M3, which is just over a lorry load which is 20 tonnes.

0.5 x 0.5 x 3.14 x 16 = 12.56 M3. I wonder if it compacts much? That could make a difference. I am assuming it will compact itself due to the depth......

What I dont know yet is whether the building inspector will be happy for us to go ahead or whether we need a Structural Engineers report to confirm.

I suppose the top may require lintels over and a reinforced pad in case the infilled well settles?

 

[Footsoldier888]

It's a shame they can't bring it inside the building and have it as a feature with some glass over it. Seems sad to be filling something that took so much effort to dig out back in the day.

 

[JohnD]

you can get a mushroom-shaped cap. The "stem" of the mushroom plugs the hole and prevents the top caving in, and the dome takes the weight of soil and superload.

They're mostly used in old mining areas. I don't know where you'd get one (or a former to cast it?)

 

[^woody^]

Don't confuse them with toadstool though, which are for something else.

 

[Ian H]

Pics, or it never happened!!

 

[^woody^]

Pics, or it never happened!!

Here's JD on a recent extension job by the colliery

 

[Nige F]

Seems sad to be filling something that took so much effort to dig out back in the day.

Now't as cold as a well diggers arse

 

[endecotp]

On big projects they seem to use foamed concrete or polystyrene blocks for things like this.
I don’t know how big it needs to be before that is worth considering.