Thanks for all the comments. Well, not the Josef Fritzl one, but hey... 
Here is some additional information
To confirm - I have nothing to do with bespokeconcrete. I am intrigued by their post and will follow up.
To clarify a few things: yes, it is for wine, so the storage space is appropriate. I always wanted to build and age a collection, but have never had a cellar space. I have realised that this house is likely to be my last - so our newbuild kitchen extension is likely to be my last chance to get a cellar. I am inspired by the spiral cellars product, and am sure they do a great job - just the price is excessive (£20-30k). Considering the install cost was much less even a few years ago, I am wondering about their margin...
My architect has suggested a standard basement across the full width of the cellar, with a concrete block wall, an inner tanking membrane and sump pump - he is confident of this approach, having done it before - but a rectangular cellar would suggest straight steps or a ladder, both of which impact what I want. Standard cellars may not offer the correct temperature / humidity requirement for what I want either.
I hasten to add that the ground is sloping away gently where we will be building, so c1m of the top of the cellar would be in the solum space anyway - for a 2m deep cellar, I would 'only' need to dig out a 2.4m diameter hole 1.5-1.8m below ground level.
So - three options:
(a) Rectangular as specified by architect but with clever stairs hinged with gas struts to lift up out of the way when you are in the cellar. A difficulty is the entry angle is wrong for safety.
(b) Hexagonal / circular with block walls and membrane as specified by architect - but inner timber/mdf shelving and spiral stairs constructed around a scaffolding pole. Could look good and be a cheaper as the hole is smaller - and well within my DIY capabilities - and could be done after the main build finishes.
(c) Require architect to follow structural approach as per commercial product (you can find an example of the full structural drawings, structural calculations and work schedule online if you look) with
- a shored hole (steel corrugated shoring layered around the hole)
- sand / concrete base
- outer ripstop liner
- butyl sealed liner (like a pond liner)
- inner ripstop liner
- concrete base slab inside inner liner
- these concrete units inside the inner liner
- ventilation pipes
Assuming the soil around the hole is stable, the gap between the outer ripstop bag and the shoring is filled with sand washed into place up to near the top of the shoring (if not, there are other options). A concrete slab is poured round the bags to form a layer where the structure reaches ground level. Concrete blocks are then built on that slab up to support the floor joists with a damp proof membrane to prevent damp rising up these block walls.
I can source the key components except the step units and corrugated shoring, but am sure that this need not be impossible. However, the architect says no builder would touch this as they would worry about leaks in the liner.
So - I can give in and not get what I want, or press on mixing a DIY project with a new build.
Either way, my stress level is increasing... What to do...
Here is some additional information
To confirm - I have nothing to do with bespokeconcrete. I am intrigued by their post and will follow up.
To clarify a few things: yes, it is for wine, so the storage space is appropriate. I always wanted to build and age a collection, but have never had a cellar space. I have realised that this house is likely to be my last - so our newbuild kitchen extension is likely to be my last chance to get a cellar. I am inspired by the spiral cellars product, and am sure they do a great job - just the price is excessive (£20-30k). Considering the install cost was much less even a few years ago, I am wondering about their margin...
My architect has suggested a standard basement across the full width of the cellar, with a concrete block wall, an inner tanking membrane and sump pump - he is confident of this approach, having done it before - but a rectangular cellar would suggest straight steps or a ladder, both of which impact what I want. Standard cellars may not offer the correct temperature / humidity requirement for what I want either.
I hasten to add that the ground is sloping away gently where we will be building, so c1m of the top of the cellar would be in the solum space anyway - for a 2m deep cellar, I would 'only' need to dig out a 2.4m diameter hole 1.5-1.8m below ground level.
So - three options:
(a) Rectangular as specified by architect but with clever stairs hinged with gas struts to lift up out of the way when you are in the cellar. A difficulty is the entry angle is wrong for safety.
(b) Hexagonal / circular with block walls and membrane as specified by architect - but inner timber/mdf shelving and spiral stairs constructed around a scaffolding pole. Could look good and be a cheaper as the hole is smaller - and well within my DIY capabilities - and could be done after the main build finishes.
(c) Require architect to follow structural approach as per commercial product (you can find an example of the full structural drawings, structural calculations and work schedule online if you look) with
- a shored hole (steel corrugated shoring layered around the hole)
- sand / concrete base
- outer ripstop liner
- butyl sealed liner (like a pond liner)
- inner ripstop liner
- concrete base slab inside inner liner
- these concrete units inside the inner liner
- ventilation pipes
Assuming the soil around the hole is stable, the gap between the outer ripstop bag and the shoring is filled with sand washed into place up to near the top of the shoring (if not, there are other options). A concrete slab is poured round the bags to form a layer where the structure reaches ground level. Concrete blocks are then built on that slab up to support the floor joists with a damp proof membrane to prevent damp rising up these block walls.
I can source the key components except the step units and corrugated shoring, but am sure that this need not be impossible. However, the architect says no builder would touch this as they would worry about leaks in the liner.
So - I can give in and not get what I want, or press on mixing a DIY project with a new build.
Either way, my stress level is increasing... What to do...
