Best sealant for old lath plaster walls

Old lath plaster walls are a classic feature in many older homes, but they can be prone to cracks, chips, and crumbling over time. To preserve their beauty and ensure their longevity, it’s important to find the best sealant for these walls.

When choosing a sealant for old lath plaster walls, it’s crucial to select a product that is specifically designed for this type of surface. Ordinary sealants may not adhere properly or provide adequate protection. Look for sealants that are specially formulated with the unique characteristics and needs of lath plaster in mind.

One of the best options for sealing old lath plaster walls is a latex-based sealant. Latex sealants are flexible and durable, making them ideal for filling in cracks, gaps, and imperfections in the plaster. They also offer excellent adhesion and can be easily applied with a brush or caulking gun.

Another great choice for sealing old lath plaster walls is a silicone sealant. Silicone sealants provide a strong and long-lasting bond, ensuring that the seal remains intact for years to come. They are also resistant to moisture and mold, which is especially important in areas such as bathrooms and kitchens.

Best Sealant for Old Lath Plaster Walls

Old lath plaster walls can often develop cracks and gaps over time, making it essential to find a suitable sealant to repair and protect the surface. There are several options available that can effectively seal these walls and extend their lifespan.

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Polycell Crack-Free Ceilings is a popular choice for sealing old lath plaster walls. Formulated specifically for use on ceilings and walls, this sealant is designed to fill and cover cracks and gaps, providing a smooth and durable finish. It is easy to apply and dries quickly, making it a convenient option for repairing old walls.

Toupret Fibacryl Flexible Filler is another excellent sealant for old lath plaster walls. This flexible filler is specially formulated to bridge cracks and gaps while remaining flexible to accommodate any movement in the wall. It is easy to sand and paint over, allowing for a seamless repair that blends with the existing wall finish.

SikaBond Construction Adhesive is a reliable sealant for old lath plaster walls that require a stronger adhesive solution. This construction adhesive provides a strong bond and can be used to fill gaps, repair loose plaster, or secure loose lath. It is important to note that this adhesive may require additional finishing, such as plastering or painting, to achieve a seamless look.

When selecting a sealant for old lath plaster walls, it is crucial to consider the specific needs of the wall, including the severity of cracks and gaps, as well as the desired finish. It is recommended to consult with a professional or conduct a small patch test before applying any sealant to ensure compatibility and optimal results.

Understanding Old Lath Plaster Walls

Old lath plaster walls are a common feature in many older homes. These walls consist of wooden laths that are nailed to the structural framing of the house and then covered with multiple layers of plaster. The laths provide a base for the plaster to adhere to, giving the walls strength and durability.

Over time, however, lath plaster walls can show signs of wear and damage. The plaster may crack, crumble, or develop holes, while the laths themselves can become loose or deteriorate. This can be especially problematic if you are trying to maintain the original character and aesthetic of an older home, as repairing or replacing these walls can be a challenging and time-consuming process.

When it comes to sealing old lath plaster walls, it’s important to choose the right product that will effectively seal and protect the surface. Look for a sealant specifically designed for use on plaster walls, as it will have the necessary properties to adhere to and protect the porous surface.

A good quality sealant will fill in any cracks or holes in the plaster, providing a smooth and even surface. It should also provide a barrier against moisture, preventing further damage and deterioration. Additionally, the sealant should be easy to apply and dry quickly, allowing you to complete the project efficiently.

Before applying the sealant, it’s essential to properly prepare the walls by removing any loose or crumbling plaster and cleaning the surface. This will ensure proper adhesion and a long-lasting seal. Once the sealant is applied and dried, you can paint or decorate the walls as desired, knowing that they are protected and sealed for years to come.

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In conclusion, understanding the unique characteristics of old lath plaster walls is crucial when deciding on the best sealant. By selecting a high-quality product and properly preparing the walls, you can effectively seal and protect these historic features in your home.

Importance of Sealants for Old Lath Plaster Walls

Old lath plaster walls offer a unique charm and character to any building, but they require proper care and maintenance to ensure their longevity. One crucial aspect of preserving these walls is the use of high-quality sealants.

Protection against moisture: Sealants are vital in preventing moisture penetration that can cause significant damage to old lath plaster walls. Moisture can lead to the breakdown of the plaster, causing it to crumble, crack, or develop mold. A reliable sealant acts as a barrier, forming a protective layer that helps keep moisture out and maintain the structural integrity of the walls.

Enhanced durability: Old lath plaster walls may have weakened over time due to age and wear. Applying a suitable sealant can help reinforce and strengthen the plaster, preventing further deterioration. It fills in any gaps, cracks, or holes, creating a smoother surface and providing additional support to the underlying layers. A well-sealed wall is more resilient and less likely to experience further damage.

Improved insulation: Sealants not only help protect the walls from moisture and damage, but they also contribute to better insulation. Old lath plaster walls often lack the insulation properties of modern materials, leading to energy inefficiency and high heating or cooling costs. By sealing the walls properly, you can reduce drafts, prevent heat loss, and create a more comfortable and energy-efficient living or working environment.

Preservation of historical architecture: Old lath plaster walls are often found in historical buildings or homes with architectural significance. Using appropriate sealants helps preserve the original aesthetics and character of these spaces. The sealant acts as an invisible shield, allowing the walls to retain their authentic appearance while protecting them from further damage. This preservation is essential in maintaining the historical value and unique charm of the property.

Cost-effective solution: Investing in high-quality sealants for old lath plaster walls is a cost-effective solution in the long run. By preventing moisture damage, reinforcing the plaster, improving insulation, and preserving historical architecture, you can avoid expensive repairs and prolong the lifespan of your walls. Regular inspection and maintenance, along with the use of quality sealants, will save you time, money, and the hassle of extensive renovations down the line.

Factors to Consider When Choosing a Sealant

When it comes to selecting a sealant for old lath plaster walls, there are several important factors to consider. These factors can help ensure that you choose the right product to effectively seal and protect your walls, while also providing a long-lasting and visually appealing finish.

1. Compatibility: It is crucial to check if the sealant is compatible with lath plaster walls. Some sealants may not adhere well to the specific materials used in these walls, potentially leading to ineffective sealing or damage to the existing plaster. Look for sealants that are specifically formulated for use on lath plaster walls to ensure compatibility.

2. Durability: The durability of the sealant is another important factor to consider. Lath plaster walls can be prone to cracking, peeling, and other forms of deterioration over time. Therefore, it is essential to choose a sealant that offers long-lasting protection against these issues, helping to extend the lifespan of your walls.

3. Moisture Resistance: Lath plaster walls are more susceptible to moisture damage compared to other types of walls. Moisture can cause the plaster to soften, crack, and deteriorate over time. Therefore, it is important to select a sealant that provides excellent moisture resistance, helping to prevent water infiltration and protecting the integrity of the plaster.

4. Ease of Application: Considering the age and condition of old lath plaster walls, selecting a sealant that is easy to apply can make the sealing process smoother and more efficient. Look for sealants that come with clear application instructions and require minimal preparation, such as sanding or priming, to ensure a hassle-free application process.

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5. Aesthetic Appeal: While the primary purpose of a sealant is to protect and seal the walls, it is also essential to consider the aesthetic appeal of the product. Look for sealants that offer a smooth and visually pleasing finish, complementing the existing plaster and enhancing the overall appearance of the walls.

In conclusion, choosing the right sealant for old lath plaster walls involves considering factors such as compatibility, durability, moisture resistance, ease of application, and aesthetic appeal. By carefully evaluating these factors, you can select a sealant that effectively protects and enhances your walls, ensuring their longevity and visual appeal for years to come.

5 Best sealant for old lath plaster walls

Everbuild General Purpose Silicone Sealant, White, 280 ml

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  • WATERPROOF SEAL – Provides a strong waterproof seal in kitchens and bathrooms around sinks, showers, baths, toilets, work surfaces, and laminates.
  • ANTI-FUNGAL – Includes anti-fungal ingredients for mould prevention in high-humidity areas like bathrooms and kitchens.
  • VERSATILE – This adaptable sealant can be used as an adhesive to secure PVCu trims, cladding, and panels.
  • CERTIFIED – Meets the European standard EN15651 for façade, cold climate and sanitary applications in compliance with the Construction Product Regulation.
  • EASY TO APPLY – Apply using a caulk, sealant/adhesive cartridge application gun such as the Everbuild Power Pro Heavy Duty Sealant / Professional Sealant Gun.

UniBond Outdoor Extreme Repair Sealant, Polymer Based Outdoor Sealant Ideal for Window and Door Frames, Weather Resistant and Waterproof Sealant, Brown, 1 x 389g Cartridge

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  • High Performance - This neutral curing silicone sealant for windows and doors provides a durable, permanently flexible seal on wooden and metal* frames, uPVC windows and cladding
  • Long-lasting – Provides a durable waterproof seal, resistant to the most extreme weather conditions. Resistant to UV and temperatures between -30°C and +120°C
  • Use indoors or outdoors - This polymer window sealant bonds to most common surfaces. It is formulated to emit lower odour levels than silicone sealants, so you're home and garden stay fresh
  • Colour co-ordinated - The brown colour allows the sealant to blend into wood and uPVC doors and window frames for professional-looking results with a lifetime guarantee**
  • Package contents - UniBond Outdoor Window and Door Frame Sealant, brown, for window and door fixtures, multi-material, waterproof, and UV resistant silicone, 1 x 392g cartridge

Everbuild Everflex 500 Bath and Sanitary Silicone, Anti-Fungal Silicone Sealant, Ivory, 295 ml

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  • IDEAL FOR BATH AND SANITARY WARE – Formulated for bathroom applications, showers, toilets and kitchens, this sealant is certified for use in high-humidity areas where sanitation is key.
  • HIGHLY FLEXIBLE – Adapts to expanding materials from temperature changes and remains permanently flexible over time.
  • PROTECTS AGAINST MOULD FORMATION – Contains a powerful anti-mould formulation that inhibits its growth to deliver a long-lasting, clean look.
  • WATERPROOF – This formula can flex and move up to 20% of the joint design and dries to provide a waterproof seal.
  • QUICK CURING TIME – cures at a rate of 3mm per 24 hours and develops a skin in just 10 minutes for a smooth, dirt-free finish.

UniBond Outdoor Extreme Repair Sealant, Polymer Based Outdoor Sealant Suitable for Use on Various Materials*, Weather Resistant and Waterproof Sealant, White, 1 x 389g Cartridge

as of July 16, 2024 7:54 pm


  • Bonding & Sealing - This premium polymer-based sealant is suitable for bonding and sealing joints indoors and outdoors. Ideal for windows, doors, and facades
  • Durable - This waterproof and weather-resistant joint sealant cures in approximately 24 hours. Suitable for indoor and outdoor use achieving long-lasting results
  • Wet surface adhesion - When fully cured, this polymeric sealant is highly resilient and it provides stronger adhesion to a wide range of damp and wet surfaces than silicone sealants
  • Polymer technology - Thanks to unique technology, the joint filler is impact and shock-resistant for the toughest repair jobs, and will not shrink over time
  • Package contents - UniBond Outdoor Extreme Repair Sealant, for sealing inside and outside, UV and weather-resistant, with polymer technology, white, 1 x 389g cartridge
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Everbuild External Frame Acrylic Sealant, Stone, 290 ml

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  • DESIGNED FOR INTERIOR AND EXTERIOR USE – Use to complete internal and external sealing around timber and metal window and door frames, plus the internal sealing of PVCu windows and doors.
  • LONG-LASTING – A no-slump formula that remains permanently flexible and has mould-resistant components for a long-lasting seal.
  • ALSO SUITABLE FOR SEALING CRACKS AND GAPS – An acrylic-based sealant that you can use for sealing cracks and gaps in brickwork, stone and concrete.
  • OVERPAINTABLE – Apply this ready-to-use thixotropic paste to most surfaces and paint over it for a seamless finish, overpainting is recommended externally to prolong the working life of the product.
  • EASY TO APPLY – Simply insert the cartridge into a sealant application gun, such as the Everbuild Power Pro Heavy Duty Sealant Gun, snip the tip and go.


What factors should be considered when choosing a sealant?

When choosing a sealant, it is important to consider factors such as the type of surface you are sealing, the intended use of the sealant, its durability, compatibility with other materials, and ease of application.

How does the type of surface affect the choice of sealant?

The type of surface you are sealing will determine the type of sealant you should use. For example, a silicone sealant is suitable for sealing glass and ceramic surfaces, while an acrylic sealant is better suited for sealing wood and concrete surfaces.

Why is durability an important factor to consider when choosing a sealant?

Durability is important because it determines how long the sealant will last and provide effective sealing. A durable sealant will withstand various weather conditions, temperature changes, and exposure to chemicals or moisture without deteriorating or losing its effectiveness.

Why is compatibility with other materials important in a sealant?

Compatibility with other materials is important to ensure that the sealant will adhere properly and form a strong bond. It is important to choose a sealant that is compatible with the materials it will come into contact with, such as metal, glass, plastic, or wood.

Why is ease of application a factor to consider when choosing a sealant?

Easy application is important as it determines how quickly and efficiently you can apply the sealant. It is important to choose a sealant that is easy to work with, spreads evenly, and can be applied using common tools such as a caulking gun.

What are some factors to consider when choosing a sealant?

When choosing a sealant, it is important to consider factors such as the type of material being sealed, the desired level of flexibility, the environmental conditions the sealant will be exposed to, the application method, and the expected lifespan of the sealant.

How do environmental conditions affect the choice of sealant?

Environmental conditions such as temperature extremes, exposure to UV radiation, and contact with chemicals or water can all affect the performance of a sealant. It is important to choose a sealant that is specifically designed to withstand the particular environmental conditions it will be exposed to, in order to ensure its longevity and effectiveness.


In conclusion, when choosing a sealant, it’s important to consider several factors. First, the type of project and the materials being used will dictate the type of sealant needed. Additionally, the durability and longevity of the sealant should be taken into account, as well as its resistance to moisture, UV rays, and chemicals. Cost is also an important factor to consider, as some sealants may be more expensive upfront but offer long-term savings. Finally, it’s crucial to follow proper application instructions and choose a reputable brand to ensure the best results. By considering these factors, individuals can make an informed decision and select the most suitable sealant for their specific needs.

Harrison Clayton

Harrison Clayton

Meet Harrison Clayton, a distinguished author and home remodeling enthusiast whose expertise in the realm of renovation is second to none. With a passion for transforming houses into inviting homes, Harrison's writing at brings a breath of fresh inspiration to the world of home improvement. Whether you're looking to revamp a small corner of your abode or embark on a complete home transformation, Harrison's articles provide the essential expertise and creative flair to turn your visions into reality. So, dive into the captivating world of home remodeling with Harrison Clayton and unlock the full potential of your living space with every word he writes.

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