What’s the difference between GRG and Jesmonite?
Posted on 9th June 2020
This is a question we regularly come across, so it is worth outlining some of the unique properties and benefits of each building material. Glass Reinforced Gypsum (GRG) and Jesmonite are both great materials that lend themselves to interior design and exterior architectural features. If you are an architect or specifier that has worked on large scale commercial projects, such as shopping centres, office buildings and transport terminals the chances are you have come across one or both of these materials. Design and Visual Concepts has over twenty years’ experience with both GRG and Jesmonite, producing moulded products such as wall cladding, column covers, ceiling domes/bulkheads and lighting troughs. Choosing between Jesmonite and GRG comes down to the material properties and benefits that best suit your application. We are perfectly positioned to assist you with choosing between GRG and Jesmonite and we welcome the opportunity to discuss your project or design in detail.
Glass Reinforced Gypsum (GRG) is made from a combination of gypsum casting plaster and glassfibre matting to add strength. It is typically used for creating bespoke interior design features.
Some notable benefits of GRG include:
- Good strength and surface hardness – impact resistant and requires little maintenance
- Excellent reproduction of fine detail – perfect for complex interior shapes and patterns
- Low expansion ensures dimensional accuracy avoiding cracking and breakage
- Large items can be constructed without the excessive weight of traditional fibrous plasterwork
- Requires minimal structural support when installing the panels
- Ideal for interior architectural features: walls, column covers, ceilings and concealed lighting
- Panels can be formed into complex shapes and curves unachievable with plasterboard
- Non-combustible (Class 0 fire rated)
Jesmonite is available as a family of materials which have applications in both interior and exterior building design. As we explain on our Jesmonite Castings page, the most popular products are AC100 and AC730, with AC100 often used for interior architectural features – it is an acrylic-modified gypsum composite. AC730, an acrylic-modified cementitous composite, can be used both internally and externally without the application of a sealer or paint system for long-term protection.
Some notable benefits of Jesmonite include:
- Excellent strength and durability, with high impact resistance
- Finishes replicating both interior (plaster) and exterior (stone) materials
- Lighter than stone, glass-reinforced concrete, sand and cement products
- Easily replicates the very finest-grain surface detail
- Water-based not solvent-based, making it kinder to the environment
- Solvent free with no VOCs
- Independently fire rated in accordance with European Fire Classification EN 13501-1
- Can be pigmented to any colour or RAL reference. It can also mimic any texture and reproduce the effect of materials such as stone, metal, wood, leather and fabric
Both Jesmonite and GRG can deliver some beautiful design features and surface finishes, some examples of which are explained on our Projects page. Each has benefits over more traditional building materials, especially when it comes to common themes like weight saving, speed of manufacture, practicality of installation and cost.
If you would like to learn more about the application of each material, receive a sample or pricing estimate please get in touch.
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