lean mix concrete ratio

wallbash

[FONT=&quot]Does sound like an unfeasibly large amount of concrete for a cavity fill[/FONT]

quote from me This is the bit I getting confused on


We need more info

Tucker

I used trenchblock on my extension. So much easier, quicker and works out cheaper to build with, by the time you have factored in the extra cost of laying 2 blocks and cavity per one trenchblock.
The cavity fill then only ended up at 150mm as well.

It's great stuff and supposed to offer better insulation properties too.

firbyfred

sorry I am confusing you all, I haven't the plans to hand but it is about 7M x 7M and it does protrude beyond the corner of the excisting building by 1M.

I did a calculation using the above site and need just under 3 tons of sand/gravel

nomis21

these are what i use...
http://www.source4me.co.uk/calculate_building_materials.php?tab=0&action=SET

wallbash

on the plan the cavity below dpc

from Post one

1.5 cubic metres to fill the cavity? It's not big.........it's massive!

Assuming you have a 100mm cavity, how long is the outer parameter?

Are we getting our terminology wrong


Are we lining a cavity or preparing the total floor area??

Tucker

Has to be the cavity. 1,5cu metres wouldn't come close to filling the floor.

To fill the floor space that size with the 150mm of concrete as needed for building regs is somewhere close on 8 cu metres of concrete

wallbash

But is 1,5cu metres too much to fill the cavity ??


Please firbyfred tell us more

Tucker

Not if it's 500mm deep at 150mm wide (as stated) and 21metres long......... it's about right, but then 150mm is a wide cavity, hence it seems an awful lot by standard cavity fills, which are 75 to 100mm.