A Filofacts on ….. CEMENT/ETC – 1
See also LIME but most CEMENT today is Portland cement – soft stone ground up and dried out. It’s mainly grey but you can buy white if you pay more. Mix it with SAND and other ingredients for most purposes. In general, use SOFT SAND for mortars, for sticking things together, and renders, for covering things over, and SHARP SAND for concrete, for building things with, or for bedding mortar for paving. But if pointing (between bricks and blocks) is to be very wide, some sharp sand will give it a bit of body. Choose the colour of the sand to suit the finish you want.
Mix in gravel or stones, too, to make CONCRETE – choose stone size to suit finish required.
Don’t make any of it any wetter than you have to – wetter it starts, weaker it dries.
In the old days, LIME was used instead of Portland cement and some builders still like a shovel of lime in a mortar mix to give it more flexibility – but nowadays a commercial plasticiser or a squirt of Fairy liquid is more common.
RECIPES (C = cement; S = sand; A = aggregate; L = optional lime.)
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A Filofacts on ….. CEMENT/ETC – 2
STANDARD MORTAR – 1C, 1/4L, 4S
REPOINT MORTAR (weaker but more flexible) – 1C, 1/2L, 5S
STRONG MORTAR – 1C, 1/2L, 3S
GRANOLITHIC mortar (for strong patching,building steps, etc) – 6 fine A, 2C, 1S
BEDDING mortar for paving – 10 gritty S, 1C
CHEAP CONCRETE – 6A, 3S, 1C
STANDARD CONCRETE (3, 2, 1) – 1C, 2S, 3A
HYPERTUFA (moss-friendly mix for plant containers) – equal parts sharp sand, peat, cement