How to mix microcement

There is no single way to mix microcement, because a microcement job is not one product. It is a stack of them, and they mix in three completely different ways.

Primer needs no mixing at all — shake it and use it. The build coat and the sealer are two-part products that get measured and combined. The microcement itself gets stirred, then thinned with water until it trowels the way you want.

Get those three straight before you start and the job goes smoothly. Mix them all the same way and you will have problems with at least two of them.

Primer: shake it, use it, do not mix it

Primer is single part and ready to use straight from the pail. Shake it well. That is the entire process.

No second component, no water, no thinning. If you find yourself reaching for a paddle here, stop. Adding water to a ready-to-use primer changes how it films out and undermines the bond layer the whole job is sitting on.

Roll one even coat, keep it uniform — no puddles, no heavy spots — and broadcast kiln-dried sand into it while it is still wet. A pail covers 600–650 sq ft and cures in 30 minutes to 4 hours.

It is the simplest step in the system and it is one coat. Good news, given how much of the rest of the job depends on it going on cleanly.

Build coat and sealer: Part A plus Part B, measured accurately

The build coat and the sealer are both two-part products. You get Part A and Part B, and they do nothing useful until they are combined.

Two rules, and they are not negotiable:

• Measure accurately. Not by eye, not by tipping until it looks about right. Two-part products cure by reaction between the parts, and an off proportion is an off cure — not a slightly softer result, a different result.
• Mix fully. All the way through, including the corners and the bottom of the bucket, and scrape the sides down. Unmixed material in the corners ends up on your surface as a patch that behaves differently from everything around it.

The build coat gets troweled into the mesh and pulled tight, with sand broadcast while it is wet. It covers 275 sq ft on the first coat and 310 on the second, and cures 12 hours after the second coat.

The sealer gets rolled and back-rolled, applied evenly, avoiding heavy areas, and recoated once dry. 650 sq ft per pail on the first coat, 750 on the second, 2-hour cure. Two coats, every job, both systems. It protects the finish and it is never optional.

One thing to be clear about, since it is described backwards nearly everywhere: our microcement is waterproof in itself, before the sealer goes anywhere near it. The sealer is not what makes it waterproof — it is protection for the finish, and you still need both coats.

How much two-part material to mix at once

Mix what you can comfortably use. We are not going to give you a working-time figure in minutes, because it is not a number that holds across every room temperature and every application style, and a made-up figure is worse than none.

What we can tell you is the shape of the mistake: people mix a full batch, spend longer than they expected on the first section, and end up fighting material that has started to go off. Mix smaller batches until you know your own pace on that particular surface, then scale up.

The coverage figures are your guide to batch size. If you are sealing a 200 sq ft floor out of a pail that covers 650 on the first coat, you are not mixing the pail.

Microcement: stir, then water until workable

The microcement is the one that takes a feel for it. Stir it, then add water until it is workable.

That is the actual instruction, and the reason it is not a recipe with a number attached is that "workable" depends on what you are doing with it. Coarse and Smooth behave differently. Wall work and floor work want different consistencies. A warm room pulls water out faster than a cool one. Your trowel technique changes what you want under it.

So: add water gradually, in small amounts, stirring between each addition. You can always add more. You cannot take it back out, and over-thinned microcement is a genuine problem — it slumps, it will not hold a trowel mark, and it goes on thinner than the coverage figures assume.

You are looking for material that holds its shape on the trowel but moves under pressure. Thick enough to stay where you put it, loose enough that you are not fighting it across the surface.

What to do with it once it is mixed

Trowel it in a cloud — irregular strokes, not neat parallel passes — and keep a wet edge so you are always working into material that has not started to set. Finish with a figure-8 float.

Then the second coat, and a 12-hour cure after it. Which product you are mixing changes the coverage you get:

Product	1st coat	2nd coat
Microcement Coarse	375 sq ft	450 sq ft
Microcement Smooth	600 sq ft	725 sq ft

Coarse is the base texture coat — large grain, natural stone look. It can be heavily sanded so it is smooth to the touch, or lightly sanded to aid non-slip properties. It suits high-traffic walls, floors and bathrooms, and it is usually hand-floated or troweled.

Smooth is the fine finish coat, with no visible grains. It gives you a plaster effect and takes a range of application styles — stucco effect, smooth over coarse, plain. It suits walls, bathrooms and low-traffic floors.

Note that both cover less on the first coat than the second. The first coat is doing the filling; the second is the one you see. That is also why mixing consistently between coats matters — a thin first batch and a thick second batch will not level out on their own.

The mistakes worth avoiding

• Thinning the primer. It is ready to use. Shake, do not dilute.
• Eyeballing a two-part mix. Measure the build coat and sealer. Both parts, accurately.
• Under-mixing. Scrape the sides and the bottom of the bucket. Unmixed material shows up on the surface later.
• Dumping water into the microcement. Small additions, stir between each one, stop when it trowels right.
• Mixing more than you can use. Small batches first, until you know your own pace.
• Mixing in a dirty bucket. Dried material from the last batch breaks up the new one and drags lumps across your finish.

Plan for the cures, not just the mixing

Each coat cures in hours, not days. But a full Reinforced job stacks seven coats with two 12-hour cures in the middle of it, so it is realistically a 2–3 day job. Core is five coats and shorter, but still not an afternoon.

Work out how much of each product you need before you start — the material calculator does it per coat — and confirm which system your surface needs on the systems page. If you are still at the stage of pricing it up, what microcement costs per square foot has the real figures, including why small areas cost so much more per foot.

And if all of this sounds like something only a trained applicator gets to attempt: that is the point of Microvella. Anyone can buy it. No certification, no trade account, no proof you work in the trade — which is not how almost any microcement in the US is sold.

Microvella ships late 2026. Join the waitlist and we will email you the day it is ready to order.