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For modern tiled wet areas, shower walls, commercial kitchens, and laundries where standard glossy sealants clash with contemporary finishes, Matt Seal S-250 Sanitary Silicone Sealant provides a clean matt finish. This neutral-curing, anti-fungal silicone contains a fungicide to inhibit mould and biological growth in hot, humid environments, including steam and spa rooms.
Matt Seal S-250 is a single-part polysiloxane silicone utilizing a neutral oxime curing system that reacts with atmospheric humidity. It cures to a permanently elastic, dustproof rubber joint. Its high elasticity accommodates ±25% joint movement, allowing it to absorb expansion and contraction between different building elements without adhesive or cohesive failure. Because it is non-corrosive, it will not degrade galvanised steel, zinc-coated steel, colourbond, zincalume, or concrete substrates. It is UV stable and colourfast, making it suitable for both indoor and outdoor service.
Suitable for internal and external joint sealing on the following substrates:
For optimum performance, design joints with a 2:1 width-to-depth ratio. Internal joints must have a minimum width and depth of 5mm. External joints require a minimum width of 10mm. The maximum joint width is 30mm with a maximum depth of 15mm. For joints deeper than 10mm, install a backing rod 25% larger than the joint width to control depth and prevent three-sided adhesion.
Apply the sealant between 5°C and 40°C on clean, dry, structurally sound substrates. For damp or porous substrates, allow concrete to cure for at least 28 days to prevent adhesion failure and subsequent mould growth. Use a two-wipe process with Acetone or 100% White Spirits on non-porous surfaces before application. Tool the joint with a moistened spatula within 15 minutes of application before the skin forms.
Yes, Adheseal Matt Seal S-250 is a sanitary grade anti-fungal silicone sealant specifically designed for wet areas including bathrooms, showers, laundries, steam rooms, and commercial kitchens. Its mould and mildew resistant formulation helps maintain a hygienic seal in humid environments.
No. Matt Seal S-250 is a silicone sealant and is not paintable. Applying paint over cured silicone may result in poor paint adhesion, peeling, or surface failure.
Adheseal Matt Seal S-250 accommodates joint movement up to ±25% of the original joint width. This flexibility helps absorb normal building movement, thermal expansion, and substrate shifts while reducing the risk of cracking or joint failure.
A stain and compatibility test is recommended before using Matt Seal S-250 on natural stone surfaces. Some stone materials may experience staining or discolouration when used with silicone sealants.
Yes. Matt Seal S-250 is UV stable and colour fast, making it suitable for both interior and exterior applications including construction joints, shopfitting, metal fabrication, and exposed architectural sealing applications.
Matt Seal S-250 adheres well to glazed and unglazed ceramic tiles, porcelain, aluminium, timber, glass, fibreglass, laminated kitchen benches, stainless steel, Colorbond, Zincalume, galvanised metal, and most common building materials.
No. Matt Seal S-250 is not recommended for permanent underwater immersion or swimming pool applications.
| Application | Key benefit | Primary trades |
|---|---|---|
| Wet area sealing in bathrooms, showers, laundries, steam rooms, and commercial kitchens | Anti-fungal sanitary-grade formulation helps resist mould and mildew growth in humid environments while maintaining a clean matt finish. | Tilers, Builders, Plumbers |
| Internal and external movement joints in construction applications | ±25% movement capability helps absorb building movement, reducing the risk of cracking, delamination, and joint failure. | Builders, Shopfitters, Contractors |
| Sealing around aluminium, Colorbond, Zincalume, galvanised steel, and stainless steel | Neutral oxime curing system will not corrode zinc-coated metals or sensitive construction materials. | Roofers, Plumbers, HVAC Installers |
| Marine and vehicle fabrication applications | Flexible silicone formulation maintains adhesion and elasticity under vibration, movement, UV exposure, and varying temperatures. | Marine Fabricators, Vehicle Builders, Contractors |
| Architectural sealing and shopfitting applications | Distinctive matt finish blends seamlessly with contemporary tiles, porcelain, laminated surfaces, and modern architectural materials. | Shopfitters, Joiners, Cabinet Makers |
| Exterior joints exposed to permanent UV conditions | UV stable and colour fast formulation helps maintain long-term appearance and flexibility outdoors. | Builders, Facade Installers, Sign Installers |
Proper preparation is essential for achieving maximum adhesion and long-term sealant performance. All surfaces must be structurally sound, dry, clean, and free from dust, grease, oils, curing compounds, loose material, and contaminants that may interfere with adhesion.
For impervious surfaces such as glass, aluminium, porcelain, stainless steel, and tiles, use the two-wipe cleaning method with Acetone or 100% White Spirits. Wipe with a solvent-soaked lint-free cloth, then immediately wipe dry using a separate clean cloth before the solvent evaporates.
For optimal movement performance, joints should ideally maintain a 2:1 width-to-depth ratio. Internal joints should be a minimum of 5mm wide, while external joints should be at least 10mm wide. For joints deeper than 10mm, install a backing rod approximately 25% larger than the joint width to control depth and prevent three-sided adhesion.
Apply Matt Seal S-250 between +5°C and +40°C. Cut the nozzle at a 45° angle to suit the required bead size. Insert the cartridge into a quality caulking gun and apply using steady, continuous pressure.
Hold the caulking gun at approximately 45° and push the sealant ahead of the nozzle. This forces the silicone firmly into the joint and improves adhesion to both sides of the substrate.
Tool the sealant immediately after application using a moistened spatula or sealant tool to create a smooth, concave finish. Proper tooling improves substrate contact, appearance, and long-term weather resistance.
Clean finishing improves both appearance and long-term seal performance. Remove excess sealant promptly while the product is still uncured.
While still wet, excess sealant and application tools can be cleaned using White Spirits and a clean cloth.
Once fully cured, Matt Seal S-250 must be removed mechanically using a scraper, blade, or specialised silicone removal tool.
Use in well-ventilated areas during application and curing. Avoid inhaling vapours, aerosols, or mists generated during use. Maintain adequate airflow, particularly in enclosed environments.
Store in a cool, dry, well-ventilated area between 10°C and 35°C, away from direct sunlight, ignition sources, and incompatible chemicals. Keep cartridges sealed until use and store upright where possible.
Uncured sealant and tools can be cleaned using White Spirits or suitable solvents. Once cured, the sealant must be removed mechanically. Dispose of waste material in accordance with local regulations.
Proper surface preparation is essential for achieving maximum adhesion, long-term flexibility, and reliable sealant performance. All substrates should be structurally sound, stable, dry, and free from contaminants before application.
Suitable substrates include glazed ceramic tiles, porcelain, glass, aluminium, stainless steel, Colorbond, Zincalume, galvanised steel, fibreglass, and laminated kitchen benches.
Surface preparation: Remove all dust, grease, oils, curing compounds, loose material, and contaminants. For impervious surfaces, use the two-wipe cleaning method with Acetone or 100% White Spirits, replacing cloths frequently to avoid contamination transfer.
Primer: Priming is generally not required due to the high bond strength of S-250. For highly stressed joints or difficult non-porous surfaces, Adheseal 50A Surface Prep may improve adhesion. Always perform adhesion testing before full application.
Suitable porous substrates include timber, concrete, masonry, and other absorbent building materials.
Surface preparation: Ensure surfaces are fully dry, clean, and free from loose particles, dust, oils, and friable material. Timber and porous substrates must be structurally sound and free from continual dampness.
Primer: For improved adhesion on porous materials, Everflex Supaprime Sealant Primer is recommended. Allow primer to flash off and dry before sealant application.
Surface preparation: Concrete must be cured for a minimum of 28 days before applying Matt Seal S-250. Surfaces should remain dry and free from dust, laitance, curing compounds, moisture, and contamination that may reduce adhesion.
Primer: Everflex Supaprime Sealant Primer may be used where additional adhesion performance is required on porous concrete substrates.
For optimal performance, sealant joints should ideally maintain a 2:1 width-to-depth ratio. Internal joints should be a minimum of 5mm wide and external joints a minimum of 10mm wide.
For joints deeper than 10mm, use a backing rod approximately 25% larger than the joint width to control sealant depth and prevent three-sided adhesion.
| Property | Value |
|---|---|
| Product Type | Polysiloxanes |
| Curing System | Neutral Oxime |
| Density | 1.03 g/cm³ |
| Shore A Hardness | 20 |
| Elongation at Break (ISO 8339) | 300% |
| Application Temperature | +5°C to +35°C |
| Temperature Resistance | -50°C to 150°C |
| Movement Capability | ±25% |
| Elastic Recovery (ISO 7389) | >90% |
| Skin Time | Approx. 20 minutes |
| Cure Rate | 2mm per 24 hours at 25°C & 50% RH |
| VOC Content | 43g/L |
| Storage Temperature | 10°C to 35°C |
| Shelf Life | 18–24 months |
| Clean Up | Uncured: White Spirit or Acetone |
| Packaging | 300ml cartridge |
Here are some common examples on where Adheseal Matt Seal S-250 Sanitary SIlicone Sealant used by our customers.
