I've just been through all this with building control and structural engineers as I had a similar problem on an extension i'm building.
The well is 2.6m deep and 600mm diameter with about 800mm of water in it (this varies) it's in what will be the corner of the extension 500mm from one wall and almost touching the other. It's built with drystone with 3 courses of brick on the top.
Structural engineer gave two options:
Fill it in: Would have to be pumped out, all silt removed and then filled up with concrete using a 'tremie pipe' to displace the water. Concrete would finish below the level of the floor slab and be covered with a compressable material (insulation) to prevent it 'sticking up' through the floor if the extension subsided.
Keep it: Pump it out, rake out all the joints to 25mm and point with 3:1 mix morter, leaving some sections of copper pipe hammered in to let water into the well. The top would need a brick collar (engineering bricks)to bring it up to floor level. The wall 500mm away will be fine, the one almost touching to be built off lintels spanning the affected area. The floor slab can be cast around the collar, with a 10mm slip barrier (insulation or foamex??) in case of minor movement. Slab to be reinforced with mesh for about a metre all around.
Building control wanted it sorted before the foundations were dug, so i've just spent a week down at the bottom pointing it. Managed to get about 30cm from the bottom - couldn't get any further without standing on my head. I spent most of the time pondering how the thing was built in the first place.
Just got to sort out an airtight toughened glass top which will bolt to the brick collar. Needs to be openable for access (lights/pump and future inspections) This won't be put on until the floor finishing goes on.
Any ideas would be good!
The well is 2.6m deep and 600mm diameter with about 800mm of water in it (this varies) it's in what will be the corner of the extension 500mm from one wall and almost touching the other. It's built with drystone with 3 courses of brick on the top.
Structural engineer gave two options:
Fill it in: Would have to be pumped out, all silt removed and then filled up with concrete using a 'tremie pipe' to displace the water. Concrete would finish below the level of the floor slab and be covered with a compressable material (insulation) to prevent it 'sticking up' through the floor if the extension subsided.
Keep it: Pump it out, rake out all the joints to 25mm and point with 3:1 mix morter, leaving some sections of copper pipe hammered in to let water into the well. The top would need a brick collar (engineering bricks)to bring it up to floor level. The wall 500mm away will be fine, the one almost touching to be built off lintels spanning the affected area. The floor slab can be cast around the collar, with a 10mm slip barrier (insulation or foamex??) in case of minor movement. Slab to be reinforced with mesh for about a metre all around.
Building control wanted it sorted before the foundations were dug, so i've just spent a week down at the bottom pointing it. Managed to get about 30cm from the bottom - couldn't get any further without standing on my head. I spent most of the time pondering how the thing was built in the first place.
Just got to sort out an airtight toughened glass top which will bolt to the brick collar. Needs to be openable for access (lights/pump and future inspections) This won't be put on until the floor finishing goes on.
Any ideas would be good!
Heard the saying "cold as a welldiggers arse" 