Outdoor microcement: complete step-by-step guide [2026]

Your terrace has been asking for a change for years, and you keep putting it off for fear of the building work. Good news: the same ready-to-use microcement that transforms bathrooms and living rooms also works outdoors. Without ripping up the existing floor, without rubble, and with the same step-by-step process you already know.

Whether yours is tiling inherited from the 90s or a slab of exposed concrete, this guide gets straight to the point. Where you can apply it outdoors (terrace, patio, façade, stairs), what it really costs per square metre if you do it yourself or hire it out, how it behaves in sun, rain and frost, and the complete application process. No fluff, as always.

Can you apply microcement outdoors?

Yes. You can apply microcement outdoors with Smartcret’s standard kits: terrace or patio floors, walls or façades, and outdoor stairs. The application is identical to indoors, with the same coats and the same timings. Only one thing changes: the weather calls the shots.

You do not need a “special outdoor” product or a different system: it is the same kit, the same primer and the same varnish you would use inside the house. And the usual condition holds outdoors too: the substrate must be sound, stable, clean and level, with no live cracks and no untreated damp. If the substrate is in poor shape, the microcement will copy it. Indoors and out.

And the pool? No: the system is not suitable for pools, neither the shell nor the edge. More on that further down.

Microcement on terrace and patio floors

The floor is where the change shows most. A terrace of tired tiles or a grey concrete slab becomes a seamless surface, with no joints for dirt to build up in, and visually connected to the interior if you repeat the colour. All at 2-3 mm thick: you do not raise levels or touch doors.

For floors, the standard kit works with Smart Base as the preparation microcement and Smart Medio as the finish, which provides the anti-slip texture and the resistance to foot traffic and abrasion. The final seal with Smart Varnish and Smart Booster protects against damp, stains and wear.

Floor kits go from 4 to 96 m², with 20 colours and a matt or satin finish: the small terrace of a flat and the large patio of a house play by the same rules.

One detail that matters more outdoors than indoors: the slope. Once sealed, microcement is waterproof and withstands rain that drains away, but not permanent puddles. Any well-built terrace already has the slope that drains the water: if yours pools, sort that out before applying.

Can you apply it over the existing outdoor tiles?

Yes, and this is exactly where the system shines: there is nothing to chip off. The process is the same as over indoor tiles: fill the joints with Smart Jointer, prime with Smart Primer PLUS (non-absorbent substrates) and apply the complete system on top. The tiles disappear under a seamless surface. You have the detail in our guide to microcement over tiles.

Compatible substrates for outdoor floors

The golden rule does not change: a sound, rigid, stable, clean and flat substrate. With that covered, outdoors you can apply over:

• Cement and concrete: the classic slab, the most common case in patios and terraces.
• Tiles, stoneware and porcelain: filling the joints and priming, just like indoors.
• Terrazzo, stone and marble: non-absorbent substrates, with their specific primer.

Where not? On wood and decking: wood “works” with temperature and humidity and would end up cracking the coating. And on any substrate with structural cracks or unresolved rising damp: fix the cause first, coat afterwards.

A note on thickness: professionals apply systems of 4-6 mm; the ready-to-use kit goes thinner, with 2-3 mm for the complete system. You renovate without added build-up, without planing doors or touching levels.

How much outdoor microcement costs per m²

Let’s get to what almost nobody backs up with figures. These are the real prices of our floor kits, verified in the shop. They include the complete system: joint filler, primer, preparation and finish microcement, varnish with booster, and sandpaper. Taxes included.

These are the kits for substrates with joints (tiles, terrazzo, marble); the kits for jointless masonry substrates sit at similar prices. On top of these list prices there are occasional offers in the shop: if you catch one, all the better for you.

And if a professional does it? The usual range in Spain is around 90-120 €/m² including labour. The maths does itself: on a 16 m² terrace, the material in DIY mode comes to around 759 €, against 1.440-1.920 € for that same surface with an applicator.

There is another factor that weighs even more outdoors: small jobs. For most applicators, a terrace of 8 or 10 m² is not worth the trip — between travel and waiting times between coats — and those who do take them on charge minimum rates that send the price per metre soaring. For those surfaces, the kit is not just the cheapest option: it is often the only realistic one.

The full breakdown by room is in our analysis of microcement prices. And the kits, with their prices in plain sight, in the collection of microcement floor kits.

Advantages and disadvantages of outdoor microcement

The advantages, quickly, because you already know them: no building work or rubble, a seamless, modern finish, applied over the existing floor, barely 2-3 mm thick, and simple cleaning with water and neutral soap.

And now the disadvantages, which is what you should read before buying:

• Microcement copies the substrate. If the slab has live cracks or sections that move, the coating will end up cracking in the same spot. Repair first: microcement is decorative, not structural.
• Wet, it is more slippery than dry, like any seamless floor. Below we explain how we handle that without kidding you.
• The varnish does the real work. Outdoors it is more exposed (sun, rain, foot traffic with grit), so periodic checks of the seal are not optional: they are real maintenance.
• No permanent puddles: it withstands rain that drains away, not standing water.

If you want the complete catalogue of things that can go wrong (and how to avoid them), we tell it unfiltered in our article on microcement problems.

Sun, rain and frost: how microcement behaves outdoors

Rain: once sealed with Smart Varnish reinforced with Smart Booster, microcement is waterproof and comfortably withstands rain that drains away. What no seamless floor tolerates — this one included — is permanent puddles.

Sun: the colour does not change in the sun. The shade you choose is the one that stays, summer after summer. The only precaution concerns application, not use: never work on overheated surfaces or in full sun, because the water in the product evaporates too soon and causes loss of adhesion, trowel marks and colour differences.

Frost: the cured system withstands winter freeze-thaw cycles. The precaution, again, concerns application: never on cold, frozen or frost-covered substrates.

And the heat? Walkable barefoot in summer, with the usual honest caveat: dark shades heat up more in the sun, like any floor.

That leaves the varnish, which takes the brunt outdoors: the seal is 3 coats of Smart Varnish with Smart Booster, matt or satin, either one. Both finishes work outdoors too.

Is outdoor microcement anti-slip?

Honest answer. The floor finish, Smart Medio, comes as standard with an anti-slip texture designed for daily foot traffic. But on every outdoor floor we advise going one step further: doing the final finish with the preparation mortar itself, which offers maximum grip and meets the slip-resistance grade required in wet areas.

The toll, said plainly: more grip means more texture, and more texture means slightly more frequent cleaning. Outdoors it pays off: a terrace spends a good part of the year wet, and that extra grip earns its keep every rainy day.

Outdoor microcement colours

The colour chart does not change when you step outside: 20 colours and two finishes, matt or satin, in all the floor kits. From mineral greys (Spike, Shale Grey) to Porcelain white, via earth tones and greens (India, Moss).

Which to choose outdoors? Continuity rules: repeating the colour of the indoor floor when the terrace opens onto the living room turns the two spaces into one. No jointed floor can imitate that effect.

The second criterion is the sun: a dark shade heats up more than a light one, like any floor, so on very sunny terraces the light ones have the edge. With any of the 20, mind you, you will be able to walk barefoot in summer.

How to apply microcement outdoors step by step

The process is identical to indoors: if you have already applied our system inside the house, you already know how to do it outside. The complete step by step, with timings and mistakes to avoid, is in the microcement application guide. The working summary:

• Prepare the substrate: clean, level and crack-free. On tiles, fill the joints with Smart Jointer (24 h of drying and sanding with 40 grit).
• Prime according to the substrate: Smart Primer ABS on absorbent ones (concrete, cement) and Smart Primer PLUS on non-absorbent ones (tiles, terrazzo, marble).
• Apply 2 thin coats of Smart Base, with around 6 h of drying and sanding between coats.
• Apply 2 coats of Smart Medio, the floor finish, sanding with 80 grit.
• Seal with Smart Varnish + Smart Booster: 3 coats, 4 h between coats and a light sanding after the first and the second.
• Respect the curing: walkable with care at 48-72 h and full resistance at 7 days.

With Smartcret no mesh is laid, not outdoors either: the system is flexible, goes on in thin coats, and adding one would only increase the thickness and the risk of cracks.

The only real difference from indoors is that outside you do not control the weather: you choose it. Apply at an ideal temperature of 15 to 25 ºC (air, substrate and material), with a margin of +5 to +30 ºC, and relative humidity of 40 to 80%; never in full sun, in strong wind, or on a frozen substrate or one with condensation. And the golden rule of outdoors: allow 48-72 hours without rain after the last coat of varnish.

Stairs, façades… and the pool question

Outdoor stairs: same system and same technique as indoors, protecting the edges and leaving them slightly rounded. You have the keys in our guide to microcement stairs.

Walls and façades: microcement on a façade is a seamless coating a few millimetres thick, applied directly onto the existing wall, with no chipping off and no rubble. On a sound substrate, sealed with its varnish, it dresses the façade in a mineral, jointless surface, also suitable for coastal settings with salty air.

The nuance is one of technique, not product: outdoors it is applied as on any wall, trowel at 45º and arc movements, as we explain in the guide to microcement on walls, and with the same weather precautions as floors.

A façade facing the sea? Yes: the system is suitable for coastal environments and salty air, on the façade and on the terrace too. The only extra discipline is the usual one outdoors: keep an eye on the varnish and renew it when the time comes.

Outdoor furniture? Microcement tables have their own guide: we will not duplicate it here.

And the pool? No. Ready-to-use microcement is not suitable for pools: neither the shell nor the edge. We would rather tell you straight before you buy.

Frequently asked questions about outdoor microcement

Can you put microcement over the terrace tiles?

Yes, with nothing to chip off: joints with Smart Jointer, Smart Primer PLUS primer and the complete system on top. It is the same technique as over indoor tiles.

How much does outdoor microcement cost per m²?

In DIY mode, the complete material comes to between 45 and 53 €/m² depending on kit size. With a professional applicator, the usual range in Spain is 90-120 €/m².

What maintenance does it need outdoors?

Cleaning with water and neutral soap and a periodic visual check of the varnish. In demanding indoor areas we recommend renewing it at most every 2 years; outdoors, that check should be at least as frequent and, at the first signs of wear, renew sooner.

How long does microcement last outdoors?

It lasts for years, and the key is not so much the microcement as the varnish that protects it. With gentle cleaning and the seal renewed in time — re-applying varnish, no building work — the surface holds up outdoors too.

Does it get very hot in summer?

It is designed to be walked on barefoot in summer too. Like any floor in the sun, dark shades heat up more than light ones: on very sunny terraces, go light.

Does it need mesh outdoors?

No. The Smartcret system does not use mesh, not outdoors either: thin coats and flexibility are the key.

How long does the whole project take?

Allow a week: coats with 4-6 h of drying, walkable at 48-72 h and full resistance at 7 days.

Is it the same kit as for indoors?

Yes: standard kits and identical application. Choose by square metres and substrate type in the floor kit collection.

Your terrace in microcement mode? Choose metres, colour and finish, and the kit arrives with the complete system inside.

RENOVATE YOUR OUTDOOR SPACE WITHOUT BUILDING WORK

Reviewed by the Smartcret technical team.