#### Rusty Wingnut

##### New Member

Assumptions:

- 6:1:1 mix ratio
- 235m² total wall coverage
- 10-12mm base/scratch coat (which will have a 10mm fibreglass mesh embedded)
- 8-10mm topcoat

- Knowing the mix ratio and the 2 coat depths, I can work out a volume.
- But that will be for a “wet” mix, and I’ve read that you should add 54% to the volume for calculating the “dry” materials you will need to order.
- But you would order materials by weight – and weight vs volume obviously varies between different materials. I believe you can work this out by knowing the specific density of the material. Normally this density is stated as Kg/m³. Again, Googling specific densities to use for sand, cement and lime often gives me a huge variable range of answers.
- So, in theory, volume + 54% split between a 6:1:1 ratio for each of the materials required, then calculated as a weight by knowing their respective densities… should tell me how much sand, cement and lime would be needed by weight. (Please assume I have already factored in contingency in the volume calculation).

I’d be really interested in knowing how others go about calculating these quantities. Thanks in advance for any guidance offered. Much appreciated.