Shock: supplier quotes less than estimates

[Hilldes]

I'm seeking quotes for insulated beam and block floor systems. I've received a quote from Milbank for their WarmFloor Pro system. For a 146m2 ground floor, been quoted approx £5K ex VAT for the system. Includes the prestressed concrete 'T' beams (155mm), EPS infill blocks, closure blocks and 150mm EPS top sheet (for a floor U value of 0.12).

 

I'd costed just a conventional B&B floor from Travis Perkins (albeit the un-discounted Ex VAT price), so the T beams and 7N concrete infill blocks. No insulation. At almost £6K.

 

Am I missing something or is that very good value from Milbank?

[Alexphd1]

Cant comment on Milbank but travis perkins usually expensive! 

[Thorfun]

this bodes well as it looks like I'm going to be approaching Milbank (along with others for comparison of course) for supply of hollow core precast slabs for our basement 'lid'! fingers crossed for a good price on that. ?

[Hilldes]

A coupe of questions on this one if anyone can help please...

• Data sheet: Specification of structural concrete toppings - "For standard concrete, the concrete sump should be class S3 (100 to 150mm) or S4 (for spot samples from initial discharge, 140 to 230mm)" - what does this mean? What do I actually specify for the groundworkers and order from the ready mixed concrete supplier?
• Can't see that WarmFloor Pro is BBA certified - not a show stopper if Building Control and warranty provider are OK?

[Mr Punter]

S3 is the slump.  The higher the number the runnier the mix.  This sounds a good system.  Do you mesh the concrete?  Is it 75mm?

[Russell griffiths]

As mr punter said s3 is the slump, how runny it will be, you will need a further specification from the floor supplier or your structural engineer, I would think the floor supplier. 

It will be the specifications for the strength and the gravel quantity and size. 

 

My spec for my walls was    C35.   10mm aggregate.  S3 slump. 

 

 

C35 is strong, got a high cement content, 10mm aggregate so it gets in all the nooks and crannies between the reinforcement, s3 slump so it will go through a pump but not like water or it will run out everywhere and the more water the weaker the final concrete. 

[Hilldes]

Thanks @Mr Punter and @Russell griffiths. The minimum depth of the structural concrete topping is 75mm as specified by Milbank - with various options for reinforcement. I'm planning a 100mm concrete topping with A142 mesh and 16mm UFH pipes embedded and clipped to the steel mesh.

 

I've asked Milbank to help refine the specification for the concrete based on the above. 

 

Any views on lack of BBA cert?

[PeterW]

BBA Cert isn’t really an issue if the system has an engineer sign it off. Don’t forget that you will need to put chairs under the A142 so 100mm will not be much more than 30mm over the UFH pipes. 

[Hilldes]

Thanks @PeterW, For sign off, I think in this case the designer/specifier is me. Got separate SEs for the timber frame and the foundations, but the insulated B&B floor is me. The chairs was my next item to look into. Milbank do specify 75mm concrete above "services" so I've asked if that applies to UFH pipes.