What Is Lime Plaster Used For?

Lime plaster is a durable and adaptable material used for various purposes for ages. It's popular among architects, builders, and homeowners thanks to its many advantages. 

In this piece, we'll delve into lime plaster's many applications and highlight the special qualities that make it a top choice for specific tasks.

Learning About Lime Plaster

Lime plaster has been used as a decorative and functional building material for millennia. Aggregate, Lime, and water are its main constituents.

The plaster's cohesive characteristics come from lime, a binder made from limestone. Sand or other natural resources can be used as an aggregate because they give the mixture strength and texture.

Types of Lime Plaster

Lime can be divided into two categories:

Plaster Of Lime Hydration

A non-hydraulic lime plaster would not carbonate properly in severely moist environments like cellars, but this one will set just fine. Because it contains less fat, hydraulic lime plaster may be trickier to apply to laths and ceilings than other types of lime plaster. However, unlike other lime plasters, this one cures in around 90 days, making it possible to paint it with a breathable finish much sooner.

Non-Hydraulic Lime Plaster

Lime putty is made from lime that does not contain hydraulic fluid. This plaster is so mild and malleable that it can preserve even the most fragile stonework. Carbonation causes a sluggish setting; the normal curing time is 12 months. When there is no chance for carbonation, non-hydraulic lime plaster can remain wet indefinitely. It's simpler to apply to ceilings and laths because it's rather "fatty" and sticky.

The utilisation of Lime-Based Plaster

Using lime plasters and washes have been around for a long time and is a simple way to give walls more depth and personality. Lime plaster and limewash are not only visually appealing, but they also insulate against extreme temperatures and protect against mould and mildew. 

Why do so many well-known examples of Greek architecture have white facades? During a cholera epidemic, lime plaster was used to coat buildings to prevent the spread of the disease.

However, lime plasters and washes can enrich walls, floors, ceilings, and furniture. It's highly malleable in addition to being aesthetically pleasing and entirely natural. Here are a few ideas for using lime finishes to spice things up.

Immediately Superior Stairway

Where might you use lime plaster? Concerning the stairs and other architectural particulars. Lime helps the stairs look more sculptural and matches the lime-washed walls.

Minor Points

Using lime plaster only requires you to finish a portion of the job simultaneously. Try using lime plaster on a small scale first to get a feel. Pick something nobody would expect, like a stove hood. If you need to cover a surface in your kitchen that will be exposed to heat and moisture, consider using lime plaster instead of paint.

Use On Top Of Masonry

You need a plain wall to apply lime plaster, but you don't have one. Bricks and other irregular surfaces are no match for a slurry mix with enough water added so that it may be spread with a paintbrush instead of a trowel. 

Camouflage Stone

The same holds for architectural elements like stonework and fireplaces. Lime plaster and stone work so well because they are made of minerals. 

Experience Texture Play

You can achieve a wide range of looks using different tools and techniques while applying lime plaster or wash. Plaster is often applied with a trowel, which can create a smooth or rough surface, closed or porous, depending on the plaster and the amount of pressure employed.

The finish is as unique as a fingerprint since it reflects the tool and the hand of the person applying it.

Limewash Can Be Used For A More Subtle Impact

Plaster adds weight and texture to a wall, both subtle and dramatic. But if you dilute it with water, you get a wash, opening up even more individualisation possibilities. 

Make A Wall Mural Behind A Fireplace

A wood stove looks great against a lime wash. Fireplace surrounds, and fireproofing are two more uses for this material. The fireplace's textured lime finish is a nice touch. 

Lime Plaster Is Great For Outdoor Use

Facades and exteriors can be given more personality with this material. 

Why Use Lime Plaster?

Although modern gypsum-based plasters have mostly supplanted lime plaster, their relevance is increasingly being recognised by individuals engaged in home improvement and the owners of historic buildings.

If that's the case, then why do we recommend lime plaster? The benefits and drawbacks of Lime Plaster will be discussed here.

The Benefits of Lime Plaster

When working on older structures, lime is often advised. However, because of its many benefits, such plaster can also be employed in contemporary structures.

Waterproof And Breathable

Due to its molecular structure, lime readily loses moisture through evaporation. That means you won't have to worry about mould growth and wetness that might arise from excess moisture.

Lime plasters also help maintain stable humidity levels. Since there is no dramatic change in humidity, this reduces the risk of some health problems (such as the flu, skin problems, and colds). 

Flexibility

Lime plasters can be quite strong while still maintaining their flexibility and adaptability. This type of plaster won't split like cement would. Thus, it's commonly utilised in older structures that "move."

Thermal Insulation

The expansive pores of lime plaster are inflated with air. Because of this, it serves as an effective thermal insulator, making it a warm and welcoming alternative to the much chillier cement.

Excellent Adaptability

While still new, lime plaster has incredible adhesive capabilities and is very easy to work with.

Long-Lasting Strength

When the plaster dries and hardens, it's rock solid. After all, walls made of lime plaster have survived for millennia. When it comes to exterior plastering, lime is a viable alternative due to its resistance to the elements.

Lime plaster is more flexible and requires no expansion joints than cement plaster. 

Aesthetics

The aesthetic appeal of such plaster has won over the hearts of many homeowners. You can customise the look of the material down to the grain size and structure by selecting from the many available finishes. 

Kills Bacteria Naturally

The alkaline composition of the substance renders it resistant to bacterial growth. It can also be used to eliminate mould.

Gains For Nature

After its useful life is up, lime can be reused in other applications. Since it is not produced using mega-plants that release tonnes of CO2 into the air, and since lime can absorb carbon dioxide, the substance is also carbon neutral.

Finally, this material does not off-gas any potentially dangerous chemicals.

Problems with Lime Plaster

There are drawbacks to using lime plasters as well:

Set Time Is Slow And Unpredictable

The drying period for lime plasters is partially consistent. It may take a long time for the material to harden. Plasters might take months to cure properly, depending on the type of lime used.

This makes the procedure less reliable and less than ideal for time-sensitive endeavours. 

Lime Plaster Can Be Quite Caustic In Some Forms.

In addition to taking a long time to set (the pH of wet non-hydraulic lime is around 12), it is also rather caustic. Workers should exercise caution when handling the material and always wear protective gear to prevent chemical burns. 

While it's true that the pH will decrease as the plaster cures, the drawback above may be an issue for some. 

Difficult To Cooperate With

Despite its adaptability, lime plaster presents a few challenges throughout the installation process.

For example, non-hydraulic lime plaster must be kept damp until it hardens. In reality, it needs to be kept damp for several days. 

Workers would have to put in much time and energy to ensure the lime plaster was always in ideal conditions.

Problems Finding Skilled Workers

These days, many skilled labourers specialise in gypsum veneer plaster or drywall installation. Because of this, locating a competent worker familiar with all the many kinds of lime plaster may be challenging. 

In the presence of water, it hardens by drawing CO2 from the atmosphere. And as the plaster dries, it contracts. With prior experience with these nuances, the outcomes of the tradesman will stay within expectations.  

For Lime Plaster, What Steps Must I Take to Get Ready?

A professional plasterer will likely do the wall preparation before applying the lime. DIYing this project, however, can result in significant cost savings. 

If the wall is made of stone or brick, scrape off any loose lime plaster and sweep away dust. In many cases, ancient plaster in quite good shape can be left alone.  

Timber lath walls require regular maintenance, including removing and replacing damaged laths and scraping away loose plaster. 

Ask your specialist to get as near as they can while applying your new lime plaster over any existing plaster you choose to keep.

Once the walls have been cleaned and are ready, a fine mist of clean water is typically sprayed upon them.

How Do You Use Lime Plaster?

Thin layers of lime plaster are often applied using a three-coat technique, with ample drying time between each coat. 

A "scratch coat" is the initial coating. This is a thin coat on top of the lath or bare brickwork that serves as the substrate. The coarse aggregate's rough, scratched finish provides a suitable key for the subsequent coat. This coating typically hardens after ten days but can take longer.

The second layer is often referred to as the float coat. It's also 10mm thick and created with coarse aggregate, but it's flatter and lightly scraped to provide a key for the top coat. It takes around ten days for this coat to dry, too.

The 4mm thin finish layer, sometimes called a "skim coat," is applied. The smooth aggregate in its construction lends a refined look to the final product. The setting time is roughly four days.

Products on the market are available to help you save time and effort when applying lime-based plaster, potentially eliminating the need for a foundation layer.

How long does it take for lime plaster to dry?

Although the first "scratch coat" should only take around ten days to cure, it can take up to three or four weeks in some situations. Therefore, a three-coat technique is typically used when applying lime plaster.

It takes another ten days for the second coat to dry and another four days for the third coat to dry.

Conclusion

Lime plaster is a durable and adaptable material used for various purposes, including decorative and functional building materials. It is composed of aggregate, limestone, and water, with its cohesive characteristics coming from lime, a binder made from limestone. Lime can be divided into two categories: non-hydraulic lime plaster, which is less fat and can be applied to laths and ceilings, and non-hydraulic lime putty, which is mild and malleable and can preserve fragile stonework.

Lime plasters and washes are used to give walls more depth and personality, insulate against extreme temperatures, protect against mould and mildew, and enhance the appearance of buildings.

They are highly malleable, aesthetically pleasing, and entirely natural. Lime plasters and washes can be used for various purposes, such as creating a superior staircase, creating minor points, using lime plaster on top of masonry, camouflage stone, and achieving texture play. Limewash can be used for a more subtle impact, adding weight and texture to a wall. It can also be used for wall murals behind fireplaces, fireplace surrounds, and fireproofing.

Lime plaster is great for outdoor use, as facades and exteriors can be given more personality with this material.

Although modern gypsum-based plasters have mostly supplanted lime plaster, their relevance is increasingly being recognized by individuals engaged in home improvement and historic building owners.

Lime plaster offers several benefits, including being waterproof and breathable, maintaining stable humidity levels, and being strong while maintaining flexibility.

Lime plaster is a versatile and cost-effective alternative to cement for exterior plastering due to its thermal insulation, excellent adaptability, long-lasting strength, and aesthetic appeal. It is more flexible and requires no expansion joints than cement plaster, making it a viable alternative for exterior projects.

However, lime plaster has some drawbacks, such as slow and unpredictable set times, being caustic in some forms, and being difficult to cooperate with.

To prepare for lime plaster, a professional plasterer can be hired, but DIY projects can result in significant cost savings. Wall preparation involves scraping off loose plaster and sweeping away dust, and regular maintenance is necessary.

Lime plaster hardens by drawing CO2 from the atmosphere, and as it dries, it contracts.

To apply lime plaster, thin layers are applied using a three-coat technique, with ample drying time between each coat. The first "scratch coat" is a rough, scratched finish on the substrate, which typically hardens after ten days.

The second layer, called the float coat, is flatter and lightly scraped, and the final 4mm thin finish layer, called the "skim coat," is applied. The setting time for lime plaster is approximately four days.

Products available to save time and effort when applying lime-based plaster can potentially eliminate the need for a foundation layer. Overall, lime plaster offers a versatile and cost-effective alternative to cement for exterior and interior applications.

Content Summary

• Lime plaster is a durable and adaptable material with many advantages.
• Lime plaster has been used for decorative and functional purposes for millennia.
• Lime, aggregate, and water are the main constituents of lime plaster.
• Lime acts as a binder made from limestone, providing cohesive characteristics to the plaster.
• Lime plaster can be divided into two categories: hydraulic and non-hydraulic.
• Hydraulic lime plaster sets well even in moist environments and cures in around 90 days.
• Non-hydraulic lime plaster is mild, malleable, and suitable for preserving fragile stonework.
• Lime plasters and washes add depth, personality, and insulation to walls.
• Lime plaster was historically used to coat buildings during a cholera epidemic to prevent the spread of the disease.
• Lime plaster can be used on architectural details like stairs for a sculptural look.
• Lime plaster can be applied on small-scale surfaces like a stove hood instead of paint.
• Lime plaster can be used on irregular surfaces like masonry and stone for a smooth finish.
• Different tools and techniques can create various textures while applying lime plaster or wash.
• Diluted lime plaster creates a wash, offering more customization possibilities.
• Lime plaster is suitable for creating wall murals behind fireplaces and for fireproofing.
• Lime plaster is great for outdoor use, adding personality to facades and exteriors.
• Lime plaster is recommended for older structures due to its many benefits.
• Lime plaster readily loses moisture through evaporation, preventing mold growth.
• Lime plaster is flexible, strong, and adaptable, making it ideal for structures that "move."
• Lime plaster serves as an effective thermal insulator, offering warmth compared to cement.
• Lime plaster has excellent adhesive capabilities and is easy to work with.
• Lime plaster dries and hardens to create long-lasting walls resistant to the elements.
• Lime plaster offers aesthetic appeal with customizable finishes and grain sizes.
• Lime plaster's alkaline composition resists bacterial growth and can eliminate mold.
• Lime plaster is environmentally friendly and carbon neutral.
• Lime plasters have a slow and unpredictable drying time, which may be a drawback.
• Lime plaster can be caustic and requires handling with protective gear.
• Lime plaster presents challenges during installation and requires constant dampness for curing.
• Finding skilled workers familiar with lime plaster can be challenging.
• Proper wall preparation is essential before applying lime plaster.
• Scraping loose plaster and cleaning the walls are necessary steps for preparation.
• Timber lath walls require regular maintenance before applying lime plaster.
• Lime plaster is typically applied in thin layers using a three-coat technique.
• The first coat, called the "scratch coat," provides a rough key for subsequent coats.
• The second coat, known as the "float coat," is flatter and lightly scraped for adhesion.
• The final layer, the "skim coat," provides a smooth and refined finish to the plaster.
• Lime-based plaster products on the market can save time and effort in application.
• Lime plaster can take up to three to four weeks to dry depending on the situation.
• Lime plaster offers waterproof and breathable properties, maintaining stable humidity levels.
• Lime plaster is a long-lasting material that has survived for millennia.
• Lime plaster is more flexible than cement plaster and requires no expansion joints.
• Lime plaster can be used to create unique and textured finishes.
• Lime plaster can be used to insulate against extreme temperatures.
• Lime plaster's molecular structure allows for the natural release of moisture.
• Lime plaster is suitable for use on fireplaces, surrounds, and fireproofing.
• Lime plaster can be used to add personality to architectural elements like stonework.
• Lime plaster is an alternative to modern gypsum-based plasters for historic buildings.
• Lime plaster is aesthetically appealing and can be customized to individual preferences.
• Lime plaster contributes to a healthier indoor environment by reducing health risks.
• Lime plaster offers an eco-friendly and sustainable choice for construction and renovation.