Cement-lime plasters

Cement-lime plaster – what it is and what it is used for

Composition and properties of cement-lime plaster

Cement-lime plaster is a mixture of cement binder, slaked lime and aggregate – most commonly quartz or limestone sand. The standard proportions are approximately 1 : 1 : 6 (cement : lime : sand), although specific Knauf products may vary slightly from this.

What are the benefits of choosing this material:

• high mechanical strength (classes CS II–CS IV in accordance with standard EN 998-1),
• good vapour permeability – the walls „breathe" and do not trap moisture,
• resistance to damp and frost, which is important for façades,
• strong adhesion to mineral substrates: concrete, brick, hollow blocks, silicate blocks,
• a pH level of 12–13, which naturally inhibits the growth of fungi and mould.

A bag typically weighs 25 or 30 kg. For a 1 cm-thick layer, you will use approximately 10–14 kg/m² – you can calculate the exact amount required for your surface using the calculator provided with the product. Allow at least 24 hours to pass between coats; the plaster reaches its full strength after 28 days. Specifications vary between products, so always check the technical data sheet for the specific Knauf plaster before purchasing.

When should you choose a cement-lime plaster rather than a gypsum plaster?

Not every wall requires the same material. Cement-lime plaster is a better choice than gypsum plaster when:

• if you’re plastering external walls or a façade – gypsum won’t withstand moisture from outside,
• are you renovating your bathroom, utility room, garage or cellar,
• the substrate is concrete or silicate and you want good adhesion,
• what matters is the hardness of the finished surface,
• The budget is limited, and machine-applied gypsum plaster works out more expensive.

Not sure which one to choose? Read our detailed post: Gypsum plaster or cement-lime plaster – a comparison.

Machine-applied and hand-applied cement-lime plasters – the differences

Machine-applied cement-lime plaster – speed and efficiency

Machine-applied plasters are products designed for use with plastering machines – they have a different grain size and higher water retention than their hand-applied counterparts. As a result, a team of two workers using a machine can apply plaster to as much as 150–200 m² a day, and the finish is uniform across the entire surface.

This solution is cost-effective when building a house, renovating an entire floor or working on other large areas exceeding 200 m² – the lower labour costs quickly offset the cost of hiring the equipment.

If you’re looking for a quick alternative to dry interiors, do have a look at our machine-applied gypsum plasters.

Hand-applied cement-lime plaster – when is it suitable?

Applying plaster by hand – using a trowel and plastering trowel without a power trowel – is still the best option for small areas, touch-ups and hard-to-reach places – as well as when you don’t want to invest in hiring a machine. It takes longer than machine-applied lime-cement plastering, but it’s accessible to anyone carrying out their own renovation work.

Uses of cement-lime plaster – internal and external walls

Cement-lime render for façades

Facades are the most common application for this material – cement-lime plaster withstands rain, repeated freezing and UV radiation (although it will eventually need to be painted or finished). It works well on silicate blocks, solid bricks, aerated concrete (provided it is primed) and ceramic hollow blocks.

Apply it to the façade in a layer 10–20 mm thick, usually in two stages: a rough coat, followed by the main coat. Before you start plastering the façade, be sure to prime the substrate – read on to find out how to choose the right primer for the substrate.

Cement-lime plaster for wet rooms

Bathrooms, kitchens, utility rooms or garages – wherever damp is a constant or recurring problem, cement-lime plaster works better than gypsum plaster. It is vapour-permeable, but it is not a damp-proof barrier – in the bathroom, apply a waterproofing layer, such as liquid membrane, before laying the tiles.

A typical layer layout is as follows: cement-lime plaster as a levelling layer, liquid membrane, and finally ceramic tiles. Do not use gypsum plaster in wet rooms – it cannot withstand constant damp.

How to apply cement-lime plaster – the basics

Preparing the substrate for cement-lime plaster

1. Check the absorbency of the surface – dampen it with water and see how quickly it soaks in.
2. Clean the surface to remove dust, grease and loose particles.
3. Prime the surface with a suitable product.
4. Moisten the substrate just before plastering, especially in summer when temperatures are high.

The plaster usually takes 12–24 hours to dry before it is ready for rendering – you’ll find the exact time on the packaging of the specific product.

Tools for machine and manual plastering

For machine-applied plaster, you’ll need a plastering machine (rental costs around 100–200 zł per day), a hose, a nozzle and a steel trowel for finishing. For manual plastering, all you need is a trowel, a steel or sponge float, an aluminium straightedge for skimming off excess plaster, and a drill with a mixer attachment for preparing the mortar.

Cement-lime products in the PK Complex range

Our shop’s range includes cement-lime plasters from Knauf – our official partner – which guarantees the authenticity of the products and full compliance with the technical data sheets.

There’s a consumption calculator for every product – you’ll know straight away how many bags to buy, with no guesswork and no buying too much. A handy tip: allow for a little more material than the calculator suggests – 10% extra for trims, corners and natural wastage is a sensible margin. For larger orders, prices are negotiable – get in touch and we’ll provide you with a personalised quote.

FAQ – frequently asked questions about cement-lime plasters

Which cement-lime plaster should you choose for external walls?

For façades, choose C-W plasters marked as class CS III or CS IV (higher hardness) and with frost resistance (designation ‘F’ in standard EN 998-1).

Can cement-lime plaster be applied by machine?

Yes – but only products labelled „for power mixers" or „for machine use". Do not mix hand-applied plaster with machine-applied plaster – differences in water retention and setting times may cause problems. Look for the „M" (machine) marking on the packaging or in the technical data sheet.

What should be the thickness of cement-lime plaster on walls?

Interior: 10–15 mm (1–2 layers). On façades: 15–20 mm. The minimum thickness of a single coat is approx. 5 mm, and the maximum thickness without reinforcement mesh is usually 15 mm. For thicknesses greater than this, use fibreglass mesh to prevent cracking.

How much does cement-lime plaster cost per bag and per square metre?

The price of a 25–30 kg bag on knaufpartner.pl is approximately 24–36 zł. Coverage is approximately 10–14 kg/m² for a thickness of 1 cm. For larger orders, you can negotiate the price – please contact us.

How does cement-lime plaster differ from lime-cement plaster?

Essentially, it is the same material – the difference lies solely in the terminology and the proportions of the binders. „Cement-lime" means more cement (harder, greater mechanical strength), whilst „lime-cement" means more lime (more plastic, easier to work with, better breathability). In practice, both terms are used interchangeably by contractors and suppliers.