Piled basement - is external insulation possible?

[Ed_]

I likely need to pile one side of my basement as can't batter back. Will be CFA piles in concrete.

 

I would like to use external insulation, mainly to avoid cold bridging at the ground floor slab. 

 

If I have a line of piles, can I place insulation against that, then cast concrete against the insulation? Is that practical? I know concrete cast against piles is fine but can't get my head around what happens with insulation in the mix as well.

 

Any experience gladly received!

[Alan Ambrose]

Errr, one method is just to use the piles as the 'shuttering' for the excavation, then a metre gap for working room, then the actual shuttering for your basement walls. Apply some external insulation before you backfill.

 

What are you doing for the other sides?

[Ed_]

The other sides are battered back, so traditional formwork.

 

I have 1m to the boundary, so 350mm piles and 250mm insulation doesn't leave me much working room!

[Alan Ambrose]

Maybe sheet piles would give you the room you need?

[Ed_]

Not really an option unfortunately, can't impact drive due to proximity to sewer in the road, and anything else is expensive. 

 

If I have to I will put the Insulation on the inside, it's not the end of the world, just trying to work out whether it is internal or external because a lot of decisions depend upon it and it's not turning out to be a straightforward decision.