11
Trade quote
Custom pricing available
Tell us what you need and we'll come back with a quote.
Custom trade quote
Share your quantity and project details for a tailored quote.
Sealant Calculator
Not sure on how much sealant you'll need? Use our calculator to find out.
Adheseal Matt Seal S-250 Sanitary Silicone Sealant is a high-performance polysiloxane sealant engineered for modern wet area tiling and specialized fabrication. Featuring a unique matt finish and a neutral (oxime) curing system, it provides a non-corrosive, UV-stable bond that accommodates ±30% movement while eliminating the high-gloss shine of standard silicones.
This professional-grade formulation is fortified with fungicides to inhibit mould growth in steam rooms and commercial kitchens, meeting Green Star low-VOC criteria for indoor air safety. To prevent delamination and adhesive failure, ensure concrete is cured for 28 days and use backing rods to avoid three-sided adhesion.
Frequently Asked Questions
How long until I can use the shower after applying Matt Seal S-250?
Matt Seal S-250 cures at approximately 2mm per 24 hours. While it will be touch dry in about 10 minutes, we recommend allowing a full 72 hours (3 days) for a standard 5-6mm bead to cure completely before exposing it to direct water pressure in a shower. This ensures maximum adhesion and long-term durability.
Is priming necessary for glazed tiles or acrylic shower bases?
For most common wet area surfaces like glazed ceramic tiles, porcelain, glass, and acrylic, priming is typically not required. However, the surface must be impeccably clean and dry. For critical applications or aged/unusual substrates, conducting a small adhesion test is always best practice to ensure certainty on the job.
Will the matt finish stain or discolour from common bathroom cleaners?
Matt Seal S-250 is formulated to be tough and chemically resistant once fully cured. However, you should avoid harsh, abrasive, or solvent-based cleaners as they can affect any silicone sealant over time. For best results, clean the area with a pH-neutral or mild detergent to maintain the integrity and appearance of the matt finish.
What is the ideal joint size for a shower corner?
For internal joints, the width and depth should be a minimum of 5mm. The ideal joint design is a 2:1 width-to-depth ratio. For example, a 10mm wide joint should have a sealant depth of 5mm. Use a backing rod to control the depth in wider joints. This ensures the sealant has the correct shape to accommodate movement without failing.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Sealing shower walls, floors, screens, and trays | Provides a long-lasting, waterproof, and mould-resistant seal with a modern matt finish. | Tilers, Waterproofers, Plumbers, Glaziers |
| Joints in kitchens, laundries, and bathrooms | Non-corrosive and safe for food prep areas once cured; resists mould in humid environments. | Cabinet Makers, Shopfitters, Plumbers |
| General construction and roofing joints | Excellent UV stability and adhesion to Colorbond®, Zincalume®, and galvanised steel. | Builders, Roofers, Plumbers |
| Marine, boat building, and vehicle fabrication | Withstands extreme temperatures (-50°C to +150°C) and remains permanently flexible. | Boat Builders, Fabricators |
Applying Matt Seal S-250: Best Practice Guide
-
Joint Design & Preparation
Correct joint preparation is the foundation of a durable, waterproof seal. All surfaces must be structurally sound, clean, dry, and free of all contaminants.
Cleaning Non-Porous Surfaces
Use the two-wipe process: wipe the surface with a lint-free cloth soaked in White Spirits, then immediately wipe dry with a separate clean cloth before the solvent evaporates.
Joint Configuration
Ensure the joint depth is half the joint width (2:1 ratio). For joints deeper than 10mm, install a closed-cell backing rod to control sealant depth and prevent three-sided adhesion.
Pro Tip: Use a high-quality painter's tape to mask off the edges of the joint. This guarantees a sharp, professional-looking sealant line and makes clean-up significantly faster. -
Application & Tooling
Apply between +5°C and +40°C. Cut the nozzle at a 45° angle to a size slightly larger than the joint. Ensure a continuous bead is applied with consistent pressure.
Gun Application
Hold the caulking gun at a 45° angle and push the sealant ahead of the nozzle. This forces the silicone into the joint, ensuring full contact with both surfaces for maximum adhesion.
Tooling Off
Immediately after applying, tool the sealant with a spatula or wetted finger to create a smooth, concave finish. This ensures good contact and a neat appearance.
Timing: You have approximately 5-10 minutes to tool the sealant before a skin begins to form. Work in manageable sections to avoid the sealant skinning over before you can finish it. -
Finishing & Clean-up
A clean finish is critical for a professional job. Any excess sealant should be dealt with immediately for the best results.
Uncured Sealant
While still wet, excess sealant and tools can be cleaned easily with a cloth soaked in White Spirits.
Cured Sealant
Once cured, the sealant must be removed mechanically by carefully scraping with a blade or using specialised silicone removal tools.
Pro Tip: If you have masked the joint, remove the tape immediately after tooling, pulling it away from the joint at a 45° angle. This will leave a perfectly sharp, clean edge.
Limitations & Safety
Product Limitations
Not suitable for totally confined spaces; sealant requires atmospheric moisture to cure.
Do not use for structural glazing, adhering mirrors, or on composite panels.
Not for permanent underwater applications such as swimming pools or aquariums.
Not suitable for horizontal walkways or other trafficable joints.
Not to be used on natural stone (e.g., marble, granite) without stain testing first. May discolour copper and brass.
This silicone is not paintable.
Safety & Handling Requirements
Personal Protective Equipment
Avoid eye and skin contact. It is recommended to wear safety glasses and chemical-resistant gloves. Wash hands thoroughly after handling.
Ventilation Requirements
Use in a well-ventilated area to maintain air concentrations below exposure standards. Ensure adequate fresh air during application and curing.
Emergency First Aid
Eyes:
Rinse immediately with plenty of water for at least 15 minutes. If irritation persists, consult a specialist.
Skin:
Wipe off excess paste with a paper towel. Wash affected area with soap and water. If irritation persists, call a physician.
Inhaled:
Move to fresh air. If symptoms develop, get medical attention.
Swallowed:
Do not induce vomiting. Wash mouth with water and give some water to drink. Contact a Poisons Information Centre or a doctor.
Seek medical attention immediately in all cases of serious exposure. Refer to the SDS for full details.
Adhesion & Substrate Guide
Ceramic, Porcelain & Glazed Tiles
Surface Preparation
Surfaces must be dry, clean, and free of dust, grout haze, soap scum, and oils. Use a two-wipe process with a clean, lint-free cloth and a suitable solvent like White Spirits to ensure no residue remains.
Primer Requirements
No primer typically required
Excellent adhesion is achieved on clean, non-porous tile surfaces without a primer.
Glass & Shower Screens
Surface Preparation
Glass must be impeccably clean and free from all manufacturing residues, fingerprints, or cleaning agents. The two-wipe cleaning process is critical for achieving a strong, waterproof bond.
Primer Requirements
No primer typically required
Adhesion to clean glass is exceptional. Ensure the surface is completely dry before application.
Aluminium, PVC & Metals
Surface Preparation
For shower screen frames and fixtures (including Colorbond® and Zincalume®), ensure the surface is clean and free from oils or protective coatings. A light scuff with a non-woven abrasive pad can improve adhesion on some coated metals.
Primer Requirements
Primer recommended for critical applications
While adhesion is generally excellent, using Primer 50A on non-porous metals is recommended for maximum long-term durability, especially in high-stress or permanently damp areas.
Laminated Benchtops & Treated Wood
Surface Preparation
Ensure surfaces are clean, dry, and free of dust and any polishing compounds. For timber, ensure it is sealed or painted and that the coating is fully cured and well-bonded.
Primer Requirements
Primer recommended for porous surfaces
For cut edges or porous materials, sealing with a suitable primer like Primer 2001 will prevent moisture absorption and guarantee a strong bond.
Downloads & technical resources
- Choosing a selection results in a full page refresh.