6 Comments on “what are the ingredients for concrete and how do you mix concrete to make a small base for a patio extension?”
Sand Cement Water = the ‘classic’ mix is (I seem to recall) 3:2:1
If you do not know anything about concrete you’d be best advised EITHER get concrete/sand premixed in packs and follow the instructions Oregon get it delivered ready made.
PS you may need FOUNDATIONS and planning permission ..
you can get bags of pre mixed concrete. you just add water and mix it up. you can use a wheel barrel
and a shovel or hoe to mix it. but its sand,cement,water and rock. 3/4 inch or pea gravel.
The basic mix is around 1 part of cement powder to 3 parts sand and 6 parts aggregate.
(A mix of only sand & cement is mortar, not concrete).
Check prices and deliveries from some local builders merchants as they may vary a bit.
Do not bother with DIY shop supplies if you need more than about a barrowful, you’d be paying several times more than from a merchant.
Some merchants sell sand & gravel mix for concrete, so you can use 1 part cement to somewhere between 6 and nine parts of that (they will advise on the mix ratio).
Unless it’s a very small amount that you can mix in a bucket or in a heap on some plastic sheet, you will need to hire a cement mixer. It should be quite cheap, especially if you get it over a weekend.
The mix should have just enough water to bind it together and give a shiny appearance, but not enough so it’s actually runny. Leave it mixing for a couple of minutes after each water addition as it does soak up. If you put too much water in, add a bit more sand & cement.
Watch out for splashes! Cement is caustic. It will irritate bare skin and can cause severe damage if you get any in your eye and do not wash it out quickly – wash them immediately if you think there is any chance you have been splashed in the face.
Once you have the correct consistency, when you drop a shovelful on a hard surface it should flow smoothly as it hits but stop while still in a conical heap.
If you need a lot, it may be cheaper to get some ready-mix delivered.
Concrete should be kept wet (by spraying with a hose) for several days whilst it cures. This happens by tiny crystals growing from the cement grains that bind the particles together, and that can only happen in water.
Ideally do not let the surface dry out for at least 7 days. If it’s simply left to dry out quickly, it will just about turn to dust! (Where ultimate strength is required, it’s kept flooded for thirty days or so).
If your not using a ready mixed concrete mix the sand/cement/agregate together dry and then add the water. This makes it easier because once you start adding water it gets heavy.
for a patio extension you need to dig out 250mm ..10 deep ..this is for 150mm ..6 hardcore and 100mm ..4 of concrete …to find amount of concrete needed ..multiply length by width …ie 10×10=100 …that’s one hundred sq ft ..4 is 1/3 of a foot ..so divide one hundred by three =33.3 cu ft …so 33.3 cu ft will cover an area 10×10 with 4 of concrete …there are thirty five cu ft in a cu metre ..27 cu ft in cu yrd ..the mix is Nine 1 ..by weight ..not volume …so its six of gravel ..either twenty mm or ten mm for size ..3 of sharp sand ..sometimes called washed ..and one of cement …if you mix by volume …ie six shovels of gravel ..3 shovels of sand ..1shovel of cement then the mix will be too weak ..a shovel of cement weights less than a shovel of sand or gravel …and remember the hardcore is just as important as the concrete ….im a builder
Normally on bags of cement there are consistency instructions of shingle to cement.Also it tells you how to make the concrete, rather than taking our advices, co’s everybody has differing views.
Denver Decorative Concrete & Custom Masonry
Sand Cement Water = the ‘classic’ mix is (I seem to recall) 3:2:1
If you do not know anything about concrete you’d be best advised EITHER get concrete/sand premixed in packs and follow the instructions Oregon get it delivered ready made.
PS you may need FOUNDATIONS and planning permission ..
you can get bags of pre mixed concrete. you just add water and mix it up. you can use a wheel barrel
and a shovel or hoe to mix it. but its sand,cement,water and rock. 3/4 inch or pea gravel.
The basic mix is around 1 part of cement powder to 3 parts sand and 6 parts aggregate.
(A mix of only sand & cement is mortar, not concrete).
Check prices and deliveries from some local builders merchants as they may vary a bit.
Do not bother with DIY shop supplies if you need more than about a barrowful, you’d be paying several times more than from a merchant.
Some merchants sell sand & gravel mix for concrete, so you can use 1 part cement to somewhere between 6 and nine parts of that (they will advise on the mix ratio).
Unless it’s a very small amount that you can mix in a bucket or in a heap on some plastic sheet, you will need to hire a cement mixer. It should be quite cheap, especially if you get it over a weekend.
The mix should have just enough water to bind it together and give a shiny appearance, but not enough so it’s actually runny. Leave it mixing for a couple of minutes after each water addition as it does soak up. If you put too much water in, add a bit more sand & cement.
Watch out for splashes! Cement is caustic. It will irritate bare skin and can cause severe damage if you get any in your eye and do not wash it out quickly – wash them immediately if you think there is any chance you have been splashed in the face.
Once you have the correct consistency, when you drop a shovelful on a hard surface it should flow smoothly as it hits but stop while still in a conical heap.
If you need a lot, it may be cheaper to get some ready-mix delivered.
Concrete should be kept wet (by spraying with a hose) for several days whilst it cures. This happens by tiny crystals growing from the cement grains that bind the particles together, and that can only happen in water.
Ideally do not let the surface dry out for at least 7 days. If it’s simply left to dry out quickly, it will just about turn to dust! (Where ultimate strength is required, it’s kept flooded for thirty days or so).
If your not using a ready mixed concrete mix the sand/cement/agregate together dry and then add the water. This makes it easier because once you start adding water it gets heavy.
for a patio extension you need to dig out 250mm ..10 deep ..this is for 150mm ..6 hardcore and 100mm ..4 of concrete …to find amount of concrete needed ..multiply length by width …ie 10×10=100 …that’s one hundred sq ft ..4 is 1/3 of a foot ..so divide one hundred by three =33.3 cu ft …so 33.3 cu ft will cover an area 10×10 with 4 of concrete …there are thirty five cu ft in a cu metre ..27 cu ft in cu yrd ..the mix is Nine 1 ..by weight ..not volume …so its six of gravel ..either twenty mm or ten mm for size ..3 of sharp sand ..sometimes called washed ..and one of cement …if you mix by volume …ie six shovels of gravel ..3 shovels of sand ..1shovel of cement then the mix will be too weak ..a shovel of cement weights less than a shovel of sand or gravel …and remember the hardcore is just as important as the concrete ….im a builder
Normally on bags of cement there are consistency instructions of shingle to cement.Also it tells you how to make the concrete, rather than taking our advices, co’s everybody has differing views.
Cheers!