Filling an old pond

[Big_Al]

I bought a house recently and 'discovered' a half built pond at the bottom of the garden (it was hidden under some decking!!). It's no ordinary pond as it has a concrete base and rendered dense concrete block walls dimensions are 14 x 6 x 6ft (LxWxD). It been part filled with general building rubble and some garden waste.

What are peoples suggestions for filling the remaining void (approx 4ft deep) with intent of topping with lawn. I'm looking for a cheap, practical solution and advice on quantities/type of materials appreciated.

I've started to demolish the top two courses of blockwork and remove the garden waste.

[seanandruby]

is the bottom exposed? you will have to smash large holes in the bottom fill with gravel and lay a good drainage membrane over it and up the sides. fill with some no fines crush and cap it off allowing for your subsoil/topsoil. cover in terran. any rubbish that is in there ie wood, paper anything that will break rot you must take out. you could use attenuation cells, see main site.

[Tony McC]

Attenuation cells (storm crates) are a bit on the expensive side as fill material, working out at 120-200 quid per m³, whereas Type 3 CGA (as used for permeable paving) would be closer to 50 quid/m³.

Sean's right about needing to pop the concrete floor, and then build up in layers, compacting each 200mm layer before placing the next.

[flowjoe]

Big Al, i might know a local contractor interested in some free tipping, whats access like ?

[Big_Al]

Thanks for the tips. Already punched a hole through the base and the sides in a few locations, not planning on building a bog garden. :;):

Unfortunately, access will be a problem as only a narrow passageway up the side of the house. Looks like I'll be doing a lot of barrowing- oh well it will keep me fit.

Better get back out there and do some more prep work.