What to choose for a seamless interior: microcement or large slabs
For a shower and a floor where reliability counts, choose large-format porcelain. Microcement is the pick when curves, niches, benches and one tone across every surface matter. Porcelain wins on wear, water and replacing a single piece; microcement wins on freedom of shape and on having no pattern that repeats.
Both give a seamless look, in different ways. A 120×280 cm slab still has joints: 1–2 mm between slabs, along the perimeter and in corners. Microcement has no joints but does crack if the substrate moves. The difference shows not in a photo but after five years.
What is more dependable in a shower: microcement or big slabs
Slabs. Porcelain does not absorb water, does not fear chemicals and does not depend on a coat of sealer. Water passes only through the joints, which are closed with epoxy grout. Waterproofing is still needed under the slabs: a liquid membrane with tape in corners and around the drain.
Microcement in a shower is possible, but it has one weak point: the sealer. It wears, and then water begins to enter the cement base. This is solved by renewing the sealer every few years, but for a long life without care, slabs forgive more. If you use the home irregularly, slabs can be ignored for years, while unmaintained microcement starts to age.
Will a 120×280 slab fit in the lift of an old building
Most often not. The lift cabin in an old Eixample building is usually around 0.8 × 1.0 m with a 60–70 cm door, and a 120×280 slab in its crate is wider and heavier still. A 6 mm slab weighs about 15 kg per square metre: 3.4 m2 is about 50 kg, and at 12 mm it is already about 100 kg, so two or three people carry it on edge with suction cups.
The options are a crane lift over the balcony or through a window, with a street occupation permit (ocupación de vía pública) from the Ajuntament; cutting the slab on site; or a smaller format such as 120×120 or 160×160. This is decided before the slabs are ordered and the delivery cost goes into the estimate. More on materials logistics in our article on deliveries and storage.
Can microcement be repaired locally
Yes, with a caveat on colour. A chip, scratch or burnt patch is sanded, filled and sealed. A patch of a particular shape tends to show, which is why the whole plane is often redone from corner to corner. With a leftover of the mix from the same batch, the colour matches better.
Replacing a porcelain slab is harder than it seems: it is bonded across its full area, and neighbouring slabs and joints depend on each other. A small chip is polished and touched up; a cracked slab is cut out, with risk to its neighbours. So when specifying porcelain, extra material is ordered: 5–10 % of area from the same lot is kept at home.
Underfloor heating and substrate
Thin porcelain heats quickly and transfers heat better than thick stone: for underfloor heating it is one of the best options. 6 mm slabs go on a flat screed, usually within 2 mm over 2 m, with flexible adhesive applied to both the substrate and the slab.
Microcement over heating also works, but needs a cured screed and mesh (see our breakdown of microcement). Both systems are sensitive to flatness: a slab breaks if there is a void under it, and microcement cracks along a substrate joint. The difference is that a void under a slab shows up at once when tapped, while hidden substrate movement under microcement appears only months later.
Which option costs less to build for the same effect
There is no universal answer. A 120×280 slab costs more in material and delivery, and the installer needs two or three people and precise tools. Microcement has cheaper material but more manual labour, coats and drying between them, and applicator rates vary widely. On large areas the gap narrows; in a shower and small zones microcement often wins, and on a living room floor the slabs do.
The real comparison comes from an estimate that shows the substrate, waterproofing, delivery (crane, permit), material, spare and labour. Ask for both options priced on your project, not on an average per metre. The effect is the same only in a photo; on site there is always a difference in tone, joints and wear.
How BCN YARD can help you choose the system
We visit the property and check the lift, the stairs, the condition of the floor slab and the heating. Then we propose a system with delivery and labour priced in the estimate. We run the project in Russian and Spanish, with staged payments under contract. Send us the floor plan and we will reply within an hour.
Frequently asked questions
What is the minimum slab thickness for a floor?
For a residential floor, 6 mm slabs go on a flat substrate and 9–12 mm where load is higher or the substrate is not perfect. Thicker means heavier and less flexible. A thin slab needs flawless installation across its whole area with no voids, so the installer matters more than the millimetres.
Are the joints between 120×280 slabs visible?
They are visible but thin: 1–2 mm with grout in a matching tone. From a distance they read as a line. Seamless is relative here: a truly continuous look comes only from microcement or resin. If you want a perfectly continuous plane, slabs are not the best choice.
Is porcelain suitable for worktops and steps?
It does: worktops and steps are made from slabs with a softened edge, but the edge needs special treatment and reinforcement. Glossy porcelain on steps is slippery, so matte is chosen. A workshop cuts and polishes the edge; such parts are not assembled by yourself.