Microcement and Lime Plaster Finishes

Seamless, softly clouded walls and floors have become one of the defining looks of contemporary interiors — the calm grey floor that runs into the bathroom without a single grout line, the warm, chalky wall that seems to glow at sunset. In Indian projects, two very different materials are used to get there. Microcement is a modern, thin, polymer-modified cement coating that can be trowelled over floors, walls, stairs, counters and even existing tiles. Lime plaster is one of the oldest building finishes in the world, made from burnt and slaked limestone, and it is behind the polished walls of Rajasthani havelis, Goan houses and Chettinad mansions.

Both are often sold with the same pictures, and that causes most of the disappointments. Microcement is applied over a tiled bathroom without checking whether the tiles are loose, and it cracks along the old joints within months. Lime plaster is applied in May in Surat, dries in a day instead of a week, and dusts and crazes. A cement-based texture paint is sold as lime, and the wall never develops the depth that was promised. This article explains what each material actually is, how it is built up layer by layer, where it works and where it does not, and what it costs in India in October 2026.

Two materials, two very different histories

Lime is ancient. Burnt lime was used as mortar and plaster across the ancient world, and Roman builders combined lime with volcanic ash to make mortars and concretes that still stand. In India, lime mortar and lime plaster were the standard building binders for centuries, until Portland cement replaced them in the twentieth century. Regional crafts developed extraordinary finishes: araish in Rajasthan, a lime plaster burnished to a marble-like sheen; the polished lime walls of Chettinad homes in Tamil Nadu; and the lime-plastered, limewashed walls of Goan and Kerala houses. Morocco has tadelakt, a lime plaster polished with stones and sealed with olive-oil soap for hammams; Italy has marmorino and stucco veneziano, the ancestors of today's Venetian plaster.

Microcement is recent. It is a manufactured product: a blend of cement, very fine aggregates and polymers (often supplied with a liquid resin to mix in), developed as a way to get the look of polished concrete in thin layers over existing surfaces. It spread through European interiors and reached Indian design studios through imported systems, with Indian manufacturers and applicators following. Its appeal is practical: a 2–3 mm layer that can cover an existing floor without breaking it, and a continuous surface that turns walls, floors and vanity tops into one object.

What microcement is, and how it is built up

Microcement is not paint and not plaster in the usual Indian sense. It is a thin, multi-layer coating system. The polymers make it adhere to a wide range of bases and give it some flexibility, the fine aggregates control texture, and the sealer on top provides stain and water resistance. A typical system has five steps: a primer matched to the substrate; one or two base coats with a slightly coarser grain, often with a fibreglass mesh embedded in the first coat to bridge joints and minor cracks; two finish coats with a fine grain, trowelled to the desired texture; and two or three coats of sealer — usually water-based polyurethane on walls and a tougher two-component polyurethane on floors and wet areas. Total build is usually about 2–3 mm.

The substrate decides everything

Because microcement is so thin, it shows every movement in what lies beneath it. A sound, dry, stable substrate is the first requirement: cement plaster or screed that has cured fully, existing tiles that are firmly bonded (tapped one by one; hollow-sounding tiles must be removed and patched), gypsum board that is properly jointed, or concrete. Structural cracks, settlement cracks and the joints between different materials — say, a brick wall meeting an RCC column — will reappear on the surface unless they are repaired and bridged with mesh. Expansion and movement joints in large floors must be carried through the microcement; covering them over is a recipe for a straight crack. On ground floors, rising damp must be addressed first, because trapped moisture can lift the coating.

Look and texture

The look is controlled by the grain of the finish coat, the trowelling technique and the sealer sheen. Fine grains trowelled hard give a smooth, slightly mottled, almost leather-like surface; coarser grains give a more mineral, stone-like texture with better grip underfoot. Colour is mixed in from pigment packs, and because every coat is hand-applied, the clouding is never perfectly uniform — that variation is the appeal, and clients should see a sample board made by the actual applicator, not only a brochure image. Matt and satin sealers hide wear better than gloss on floors.

Microcement in bathrooms and kitchens

The single most photographed use of microcement is the seamless bathroom, and it is also the one most likely to fail if detailed carelessly. Microcement and its sealer resist water on the surface, but they are not a waterproofing system on their own. In a shower area, the correct build is a waterproofing membrane (cementitious or liquid-applied, as recommended by the microcement manufacturer) over the screed and up the walls to at least shower height, with corner tapes at the wall–floor junction and sealed collars around drains and pipe outlets. The floor must fall to the drain — typically around 1 to 2 per cent, more inside the shower — because microcement will not correct a flat floor. Linear drains suit microcement well because the floor can be sloped in one plane.

In kitchens, microcement works well on walls and floors and can be used on counters, but it is softer than granite or quartz and its sealer is the only barrier against hot pans, turmeric, oil and lemon. Most designers keep microcement to the walls, floor and island sides, and use stone or quartz on the main cooking counter. Where microcement is used on a counter, trivets and prompt wiping become part of daily life, and periodic resealing should be expected.

What lime plaster is, and why it behaves differently

Lime plaster starts as limestone, which is burnt in a kiln to drive off carbon dioxide and make quicklime. Quicklime is slaked with water to make calcium hydroxide — as a wet lime putty or a dry hydrated lime powder. Mixed with sand and applied to a wall, the lime slowly absorbs carbon dioxide from the air and turns back into calcium carbonate: chemically, the plaster becomes limestone again. This is called carbonation, and it happens from the surface inwards over weeks and months, which is why air-lime plaster must not dry out too fast. Hydraulic limes, made from limestones containing clay, set partly by reaction with water as well, so they harden faster and tolerate damper conditions.

These chemistry facts translate directly into how lime behaves on a wall. Lime is vapour-permeable — moisture inside a wall can escape through it — so walls plastered in lime tend to stay drier and healthier than walls sealed in cement and acrylic paint, especially in old masonry and in humid coastal climates. It is softer and more flexible than cement plaster, so it accommodates small movements with fine hairline cracks rather than large ones, and fresh lime can partly heal hairline cracks as free lime is carried into them and carbonates. It is strongly alkaline when fresh, which discourages mould. Against that, it is slower to apply, needs careful curing, is less resistant to knocks than cement plaster, and needs a skilled mason.

The coats of a lime plaster

Lime plaster is traditionally applied in three coats, each thinner and finer than the last. The first or scratch coat, about 10–12 mm, is pressed hard into a dampened wall and scratched to give a key. The second or floating coat, about 8–10 mm, is ruled flat and rubbed up with a float to compact it. The finish coat, about 2–3 mm of fine lime with fine sand or marble dust, is trowelled, and for polished finishes such as araish or Venetian plaster it is burnished repeatedly as it stiffens. Each coat must be allowed to firm up — often a day to several days depending on weather and lime type — and kept damp, before the next is applied. Mixes for base coats are commonly about one part lime to two-and-a-half or three parts well-graded sand by volume, but the right mix depends on the lime and the sand, and should follow the supplier's guidance or IS 2394, the Indian code of practice for lime plaster finishes.

Lime in a hot, humid climate

In Surat and coastal Gujarat, the challenge is not humidity — lime likes moisture while it cures — but heat, wind and direct sun, which can dry a fresh coat in hours. A dried-out lime plaster has not carbonated; it stays soft and dusty and may craze. The answers are traditional and simple: work on shaded walls, avoid the hottest months and hours where possible, hang wet hessian or shade nets, mist the surface lightly several times a day for the first days, and never apply over a wall that is bone dry (dampen it first) or soaking wet. Monsoon rain on an unprotected external wall can wash out fresh lime; protect it until it has firmed. External lime plaster is usually finished with limewash, which is renewed every few years.

Microcement or lime: choosing by room and by problem

The two materials overlap in look but not in behaviour. Microcement is a sealed, wipeable, seamless skin: it suits floors, wet rooms, stairs and furniture, and it suits renovations where breaking an existing floor would be costly. Lime is an open, breathing, hand-made plaster: it suits walls, especially old walls, damp-prone walls and rooms where a soft, natural texture and a healthier indoor surface matter more than scrubbability. Neither is a substitute for good waterproofing, good substrate preparation or a skilled applicator.

For most Indian homes, the sensible pattern is selective use. A microcement floor running from living room into a guest bathroom, or a microcement vanity and shower wall, gives the seamless look where it is most visible. Lime plaster or limewash goes on one or two walls where texture and warmth matter — a living-room feature wall, a bedroom headboard wall, a pooja room — and on old walls being restored. Ordinary emulsion covers the rest. In heritage buildings, the rule is firmer: original lime masonry should be repaired with lime, not cement, because cement plaster traps moisture in the wall and can accelerate decay of soft bricks and stone.

Application process and timelines

Both finishes take longer than paint, and both need protection from other trades. A microcement floor should be the last wet trade in a room, after ceilings, electrical chasing, painting of adjoining surfaces and carpentry fixing are complete, because a dropped tool or a dragged ladder can mark it before the sealer has cured. Lime plaster needs the opposite sequence for its own cure: it is applied early enough to be kept damp and shaded, and before the room is closed and air-conditioned.

Care, cracks and maintenance

Microcement is cleaned with a damp mop and a pH-neutral cleaner; bleach, acids, ammonia and abrasive scrubbers damage the sealer. Felt pads under furniture prevent scratches, and a doormat at the entrance keeps grit from acting as sandpaper. In heavy-traffic areas a maintenance coat of sealer every few years renews the protection — the interval depends on use and the sealer type. Hairline cracks usually trace a movement in the substrate; they can be filled and locally recoated, but the repair may be visible, which is why prevention through substrate checks is so important.

Lime walls are dusted and, if needed, wiped gently with a damp cloth; they should not be scrubbed or painted with ordinary acrylic emulsion, which would seal the surface and defeat the point. Small marks are often best left to patinate, or touched in with limewash. Hairline cracks in fresh lime are normal and often close as carbonation continues; larger cracks indicate movement in the wall and need investigation, as with any plaster. This site's guide to wall cracks explains how to tell a surface crack from a structural one.

Where these finishes are heading

Interest in lime is rising for reasons that go beyond appearance. Lime is produced at lower kiln temperatures than Portland cement and reabsorbs carbon dioxide as it carbonates, which makes it attractive to designers looking at the embodied carbon of materials, although its full environmental performance depends on fuel, transport and the amount used. Heritage conservation in India increasingly insists on lime for repairs, which is keeping traditional craft skills alive. Microcement manufacturers, for their part, are developing lower-odour water-based sealers, mineral-based and lime-based variants that breathe better, and products with better UV stability for terraces and facades. The direction for both is clear: fewer joints, more natural textures, and finishes judged on what they do for the wall and the room, not only on how they photograph.

Rules for specifying microcement and lime

• Decide the job first: sealed and seamless (microcement) or open and breathing (lime) — they are not interchangeable.
• Inspect the substrate before quoting: tap every tile, check for damp and map every crack and joint.
• Never use microcement as waterproofing; put a proper membrane under it in showers and fall the floor to the drain.
• Carry expansion and structural joints through microcement floors instead of hiding them.
• Use floor-grade two-component sealer on floors and wet areas, and keep oil, haldi and acids off unsealed surfaces.
• Apply lime plaster only on dampened walls, in shade, and keep it damp for the first days; avoid fierce sun and wind.
• Repair old lime masonry with lime, never with cement plaster.
• Approve a sample board made by the actual applicator on site, in the actual light, before work starts.
• Ask for the system data sheet and a written statement of coats, thicknesses and sealer type in the quotation.

Frequently asked questions

Can microcement be applied over existing tiles?

Yes, if the tiles are firmly bonded, clean and free of damp. Each tile should be tapped; hollow tiles must be removed and patched. Grout lines are filled and a mesh is embedded in the first base coat to stop the old joints telegraphing through. Loose or moving tiles will crack the microcement.

Is microcement waterproof?

A properly sealed microcement surface resists water and is used in bathrooms and showers, but it is not a waterproofing system. In wet areas it must be laid over a waterproofing membrane with sealed corners and drain collars, and the floor must slope to the drain.

Does microcement crack?

It can, usually where the substrate moves — over loose tiles, unrepaired cracks, junctions between different materials or hidden expansion joints. Good substrate preparation, mesh in the base coat and carrying movement joints through the finish prevent most cracks.

Is lime plaster better than cement plaster?

It is better for some jobs. Lime is breathable and flexible, so it suits old masonry, damp-prone walls and soft, natural finishes. Cement plaster is harder, faster and cheaper, and suits most new construction. For historic buildings with lime mortar, lime is the right choice for repairs.

What is the difference between lime plaster and limewash?

Lime plaster is a thick plaster of lime and sand, applied in coats of several millimetres. Limewash is a thin, watery lime paint brushed on in several coats over lime plaster or a suitable base, giving the characteristic cloudy colour. Many products sold as limewash today are lime-look mineral paints.