Lime Plaster Guide: Everything to Know About Its Benefits

Most modern homes use drywall and gypsum plaster to finish their walls. However, did you know there’s an alternative that has been used for thousands of years?

Lime plaster has been used to finish walls for centuries and, even now, it offers different advantages to modern builders. This type of plaster can create a rustic look, with the added benefit of air purification. Here’s a simple guide explaining what lime plaster is, how it is made, as well as its benefits and uses.

What is Lime Plaster?

Whilst modern plaster consists of gypsum or cement, lime plaster is an ancient alternative made of sand, water and lime. Thought to have been first used around 7000 BC, it has been the traditional choice for plastering buildings. It is characterised by its natural, rough appearance and is increasingly used for this effect.

Lime plaster hardens when the lime element reacts with another substance. Commonly, there are two types of lime you can use:

Hydraulic Lime – this lime sets when it reacts with water. It sets faster and is more durable than non-hydraulic lime, suiting it to external use
Non-hydraulic lime – this lime sets when it reacts with air (carbonation). It takes longer to set and is more flexible than hydraulic lime, so it is often used indoors. You may hear this type of lime called lime putty

Fibres like animal hair have been implemented in the mixes in the past to increase the strength and security of bonds.

What Does Lime Plaster Look Like?

Identifying lime plaster can be difficult if you do not know what you are looking for. Lime plaster is usually an off-white colour compared to the pinkish brown of gypsum alternatives. It is likely to be unfinished on the walls and has a rough texture.

Over the last one hundred years, it has been used scarcely, but if your building is older than that, it may have lime plaster. Then you can check lath, cob and masonry walls as they are often plastered with lime.

How To Make Lime Plaster

With only three ingredients, the recipe for lime plaster is simple. The ratio is one part lime to two and a half parts sand. The amount of water you add depends on your desired consistency.

However, it should only be mixed by a professional, as wet lime plaster can chemically burn the skin, and incorrect mixing will directly affect the strength and usability of the plaster. Here’s the process the plasterer will follow:

Start with one part of coarse sand
Mix in one part of lime
Then add another one and a half parts of sand
Mix these materials dry for five minutes.
Then slowly add in clean water whilst continuing to mix. Stop mixing when you have reached your desired consistency.

The Process

After the plasterer has mixed the lime, they will apply it in three coats. It is a long process; each layer takes days to set.

Firstly, they will remove any loose plaster or building materials to provide a clear surface to plaster onto. For example, if your wall is made of timber lath, they will repair and replace any damaged laths.

Once the walls are clean, the plasterer will mist them with clean water so that the plaster adheres to the surface. This mist is fine enough to make the wall damp but not dripping wet.

Then they will apply the first coat of plaster, called a ‘scratch coat’. This layer is applied directly to your building material, whether that is lath, brick or masonry, and forms the foundations for the other layers. It is around 10mm thick, uses a particularly coarse plaster and is scratched to produce a rough surface for the next coat to bond to. The plasterer will leave it for around ten days to dry.

The next coat is called the ‘float coat’ and is applied once the initial one has dried. Similarly to the first coat, it is 10mm thick and uses a coarse plaster mix, but crucially the plasterer will smooth it flatter. They will still rough the surface for the next coat, though it will not be as much as the scratch coat.

After another ten days of drying, the plasterer will apply a final 4mm thick ‘skim coat’. This layer will consist of a smoother mix that the plasterer carefully flattens out. Unlike the previous coats, they won’t rough the surface to maintain a decorative finish. Once applied, this final, thinner layer is given around four days to set.

Why You Should Use Lime Plaster

Most modern buildings use drywall or gypsum plaster, due to their ease of use and shorter drying times. This does not make lime plaster obsolete; however, as it has many benefits:

Breathable material

Unlike cement or polymer-based plasters, lime allows air to flow through it. This breathable nature helps moisture escape, improving your air quality with a consistent flow through the room and preventing damp forming. Additionally, its high pH means it is a fungicide that also prevents any dampness.

Long Lasting

Lime plaster has tiny particles that fill the smallest gaps in your walls, creating a strong bond. Over time calcite crystals form, making the plaster stronger over time; we still have examples of lime plaster from the ancient Roman city of Pompeii (see below).

Flexibility

Due to its soft nature, lime plaster can be spread easily. It is less likely to crack than brittle materials, such as cement plaster, so it does not require expansion joints.

Attractiveness

Using lime plaster in modern decorating has become an aesthetic choice. It gives a unique natural finish that is reminiscent of rustic, older buildings. This effect makes it perfect for traditional architecture.

Eco-Friendly

With three natural ingredients, lime plaster does not require long industrial processes to produce. Additionally, the lime absorbs carbon dioxide from the atmosphere, offsetting greenhouse gas emissions.

Some Considerations

Though lime plaster has several benefits and suits multiple scenarios, there are some things to consider to ensure it is the right type of plaster for you.

Number Of Coats Required

Typically, a plasterer will apply two coats of gypsum plaster to a wall. However, lime plaster usually requires three coats: an initial scratch coat, a float coat, and a final skim coat. These layers take longer to set and apply.

Drying Time

Whereas modern gypsum plaster dries in hours, lime plaster takes days. The initial scratch coat generally sets in ten days, then the float coat will set in another ten days, and then four days for the skim coat.

It is important to remember that room conditions impact the drying time. The ten-day estimate works for a room in stable conditions, but some situations can result in drying times of three to four weeks.

Risks

When wet, lime plaster has an alkaline pH of 12, meaning it can cause chemical burns if in contact with your skin. After the plaster dries, the pH falls to 8.6, reducing the risk of harm. We recommend you enlist the help of a trained professional to apply lime plaster.

Using Lime Plaster in Modern Retrofit Projects

Lime plaster isn’t just for listed buildings and traditional restoration. It is now part of a much wider conversation around retrofit, breathable construction and moisture-safe renovation. As more property owners look for ways to improve comfort and energy efficiency in older homes, lime plaster is being reconsidered as a practical material rather than simply a heritage one.

This matters most in solid-wall properties, period homes and buildings that need to release moisture naturally. In these settings, impermeable modern finishes can create avoidable problems by trapping damp within the wall structure. Lime plaster works differently. It supports a more breathable approach, which can make it a better fit where compatibility with older materials is essential.

Improving Ventilation in older houses

Older properties are now more likely to undergo insulation upgrades, ventilation improvements and whole-house renovation works than they were a few years ago. That means more homeowners are asking not only what lime plaster is, but whether it is suitable for walls that need to balance thermal performance with moisture movement.

When to Use Lime Plaster

Lime plaster is often worth considering where:

the property has solid walls
the building is older and originally used lime-based materials
previous cement-rich repairs have caused hard, less breathable patches
the wall needs to manage moisture rather than trap it
a breathable decorating system is planned

This does not mean lime plaster is always the right answer. It means it should be assessed properly where wall performance, compatibility and breathability matter.

Lime Plaster and Breathable Wall Systems

One of the biggest reasons lime plaster is gaining attention again is its role in breathable wall build-ups. In the right property, it can work well alongside compatible finishes and renovation methods that allow moisture vapour to pass through the wall rather than becoming trapped behind dense surface coatings. Every element should be breathable, so paint lime plaster with a breathable finish.

That is particularly relevant in stone properties, older brick buildings and homes with a history of damp or condensation-related issues. If a wall has already struggled because of hard cement repairs or non-breathable paint systems, replacing those layers with more compatible materials can help the wall perform more naturally.

Not a shortcut

It is still important to avoid oversimplifying the subject. Lime plaster does not fix every damp problem on its own, and it is not automatically the best choice for every room or property type. The value lies in using it where the background, age of the building and moisture behaviour make it appropriate.

For that reason, this section helps position lime plaster as part of a broader decision about the wall system, not just the final finish.

How to Decide Whether Lime Plaster Suits Your Project

If the property is older, has solid masonry walls or has experienced issues after hard modern repairs, lime plaster may deserve serious consideration. If the background is modern, stable and dry, gypsum may still be the more practical option in some cases.

Lime Plaster vs Gypsum Plaster

Lime plaster may be the better choice if:

the building needs breathable materials
the wall has traditional masonry construction
the project involves sympathetic restoration
moisture movement through the wall is part of the design consideration

Gypsum may be more practical if:

the property is modern and built for dense, sealed finishes
speed and cost are the main priorities
the wall build-up does not require vapour permeability
the repair area is straightforward and not part of a traditional system

Great Places To Use Lime Plaster

As we’ve already mentioned, lime plaster’s natural, rustic aesthetic makes it perfect for traditional buildings. Here are a few more examples of situations where lime plaster is perfect:

Over Stones or Masonry

If you have stone and masonry walls, lime plaster can highlight the individual stones whilst protecting your walls. Its small particles work their way into the natural gaps of the building materials to create a solid bond.

Add Texture

The natural imperfections in the surface of lime plaster add texture to your walls. You can use it to create an accent wall in a room. Ask your plasterer about how they can achieve different finishes.

On External Walls

A lime slurry can cover the bricks of your home and create an off-white finish.

Does It Need Painting?

Lime plaster is most often used as a standalone finish due to its natural texture and breathable properties. Painting onto lime plaster is not recommended as the paint is rarely breathable, so you lose the plaster’s air-regulating benefits. Plus, it masks the plaster’s appearance.

However, as lime plaster is off-white, you may want to add colour to your walls. You can use a lime wash to colour and conserve your lime plaster. Its porous and alkaline properties maintain the plaster’s benefits.

If you want to paint over lime plaster, choose a breathable paint that is suitable for use on lime. A matt colour helps replicate the appearance of the plaster.

Benefit From Our Expertise

If you’ve decided that you want to use lime plaster to create a textured finish on your walls, you can enlist our professionals to apply it.

At A B Drylining, our team is CSCS-certified and PASMA and IPAF-accredited. We complete plastering jobs for commercial clients throughout the South West of England, including Bristol, Bath and Swindon and handle your plastering requirements, whether they are lime plastering or Monocouche rendering.

Contact our friendly team today for more information and to receive your free quote online.

FAQ

Which is better: lime or gypsum plaster?

Lime and gypsum plaster have different advantages. If you want a standard finish to your walls that you can decorate over, gypsum is the best, most affordable option. However, if you want a natural text and aesthetic, a breathable plaster, or an eco-friendly option, lime plaster is the right choice.

Can you buy modern types of lime plaster?

Yes, you can buy modern lime plaster that adheres to British Standards Regulation BS EN 998-1:2016.

How are lime plaster and cement plaster different?

Lime plaster and cement plaster are made of different materials. Lime plaster consists of sand, water and lime, whereas cement plaster consists of sand, water and cement. These varying recipes give the plasters different properties.

How difficult is lime plastering?

Lime plastering should be done by a trained professional, as the plaster can cause chemical burns to the skin.

How can I prepare my walls for lime plaster?

Remove all debris, such as loose plaster or building materials. If you have lath walls, repair any broken laths. Then mist the wall with a fine spray of clean water.

How long should I leave lime plaster to set?

Lime plaster takes longer to set than modern gypsum alternatives. In typical conditions, each coat takes around ten days to set, depending on its thickness. However, if the air conditions in your room are different, it can take as long as three to four weeks.

Can I paint on lime plaster?

Yes, you can paint onto lime plaster, but it is not recommended as you could forfeit its breathable nature. Instead, you can use a lime wash to colour and protect the plaster.

How expensive is lime plaster?

Using lime plaster is generally more expensive than using gypsum or cement plaster. You will incur higher labour fees as you need to hire a plasterer for longer and the raw materials cost more.

Lime Plaster Guide: Everything You Need To Know