How to Mix Concrete

To mix concrete, combine the dry materials first — or empty your bags — then add water a little at a time until the mix is plastic and workable, holding its shape without being soupy. Whether you mix by hand in a tub or run a power mixer, the rules are the same: mix dry, add water slowly, and do not overdo the water.

Concrete is heavy and time-sensitive. A wheelbarrow of mixed concrete weighs well over 300 lb, and you have roughly 30 to 90 minutes before it starts to set, so have your forms ready and only mix what you can place.

Mixing by hand

Use a mortar tub, wheelbarrow, or mixing tray. Empty your bagged mix (or batch cement, sand, and stone at 1:2:3), then fold it dry with a hoe until the color is even. Pull the dry mix to one side, pour in part of your water, and drag the dry into the puddle a little at a time. Keep adding water in small amounts until every bit is wetted and the mix is uniform — about 3 quarts per 80 lb bag is typical.

Mixing in a power mixer

Start the drum and add a little water first so material does not cake on the back. Add about half your stone, then the cement and sand, then the rest of the stone, then the remaining water in small amounts. Let it tumble two to three minutes until uniform. Do not fill past about half the drum's rated capacity, or it will not mix cleanly.

How to tell when it is right

Good concrete is plastic and cohesive: cut a trench in it with your hoe and the sides should hold their shape and the surface should glisten without free water pooling. If it crumbles, add a splash of water; if it slumps and runs, add a little dry mix. The goal is workable, not wet.

Batch size and timing

Only mix what you can place and finish before it stiffens — in hot, dry, or windy weather that window shrinks. For anything past roughly a cubic yard (about 45 eighty-pound bags), priced ready-mix delivery usually beats hand-mixing on both effort and consistency. Use the bag calculator below to size your order.

Common questions