I have 33m2 of patio are to lay patio slabs on, one are is 9x2.4 (this has a concrete base) the other 5x2.4 this is on a scalpings base. I have tried to work out how much sand and cement I need bulk order using your calculators, but I'm confused. I was going to work on a 6 to 1 basis for my mix. But have worked out that I need approx 9 tonnage of sand. Is this right. if so how much cement would I need and what type, my slabs are black slate and also need some advice on how to make the grout mix darker to match the slabs.
If using the project, material volumes you can put your total length of 14.4m into the length box followed by your width of 2.4 ( =33.6m2 not 33m2) then in the depth box you put 0.05 which is 50mm or 2 inches. This gives you a volume of 1.6 cubic meters of course, dry sand which will weigh 3 tonnes. For this 3 tonnes of sand you will need Â½ tonne of cement to be able to mix at 6 to 1 by weight.
You can buy black cement colouring agent from builders merchants to darken your grout but be sure to mix this powder with the cement before you mix the sand and water in.