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Adheseal Matt Seal S-250: A Product Overview
For tilers and waterproofers, the finish is everything. Adheseal Matt Seal S-250 is a professional-grade, neutral cure sanitary silicone engineered specifically for wet areas where both aesthetics and performance are non-negotiable. Its distinctive matt finish provides a modern, seamless look that elevates the appearance of tile, glass, and joinery, moving beyond the standard glossy sealants.
Underneath its unique finish is a high-performance formula. Packed with a powerful fungicide, it delivers exceptional resistance to mould and mildew growth, even in the hot and humid conditions of Australian bathrooms and laundries. As a neutral (oxime) curing silicone, it offers superior adhesion to a vast range of materials without the risk of corrosion, making it the reliable choice for sealing everything from porcelain tiles and acrylic shower bases to Colorbond® and aluminium frames. Get the job done right, first time, with a sealant that looks as good as it performs.
Core Features & Specifications
- Distinctive Matt Finish: Delivers a contemporary, low-sheen appearance that complements modern tiles and tapware, eliminating the harsh reflections of traditional silicones.
- Advanced Anti-Fungal Formula: Actively inhibits the growth of mould and mildew, ensuring a clean, professional finish that lasts in steamy showers and humid laundries.
- Neutral Cure System: Non-corrosive and low-odour, making it safe for use on sensitive surfaces like Zincalume®, galvanised steel, and laminated benchtops.
- Permanent Flexibility (±30% Movement): Accommodates significant joint movement and thermal expansion without cracking or losing adhesion, crucial for dissimilar materials like tile and glass.
- Excellent Adhesion Profile: Bonds tenaciously to glass, ceramic tiles, porcelain, aluminium, PVC, and treated wood, providing a versatile solution for the entire job site.
- UV & Temperature Stable: Withstands permanent UV exposure and service temperatures from -50°C to +150°C without degrading, making it suitable for both internal and external applications.
The Matt Seal S-250 Advantage
- Eliminate Callbacks from Mould: The potent fungicide gives you the confidence to stand behind your work in wet areas, preventing costly and reputation-damaging mould issues.
- Achieve Modern Aesthetics: Offer your clients a premium, architectural finish that sets your work apart from the competition and aligns with contemporary design trends.
- Work with Confidence on Any Surface: The neutral cure formula and broad adhesion profile mean you can carry one cartridge that handles virtually every sealing task in a bathroom or kitchen fit-out.
- Guarantee Long-Term Performance: Deliver a tough, waterproof, and flexible seal that won't shrink, crack, or peel, ensuring the job is done right, first time, every time.
Proactive Troubleshooting
Scenario: Applying to Damp Surfaces
Potential Outcome: The sealant fails to cure properly, resulting in poor adhesion, bubbling, and ultimately, a failed joint that will leak and require a complete re-do.
Adheseal Best Practice: Ensure all substrates are completely dry before application. For non-porous surfaces like tiles and glass, use the two-wipe process with a solvent like White Spirits to remove any invisible moisture or residue. It’s a simple step that guarantees a professional outcome.
Scenario: Three-Sided Adhesion in a Joint
Potential Outcome: The sealant is bonded to the back of the joint as well as the sides, restricting its ability to move. This leads to high stress at the bond line, causing the sealant to tear and the joint to fail prematurely.
Adheseal Best Practice: Always use a closed-cell backing rod or bond-breaker tape in the base of the joint. This ensures the sealant only adheres to two sides, allowing it to stretch and compress as designed. This is the sure way to achieve the specified ±30% movement capability and prevent callbacks.
Applications in Practice: Trade Scenarios
For Tilers & Waterproofers: Sealing a Frameless Shower
The Professional's Challenge
Ensuring a perfectly waterproof and mould-free seal in the high-movement corner joints of a shower and along the base of a frameless glass screen, while delivering a high-end finish that matches modern decor.
The Adheseal Solution
Use Matt Seal S-250 for all perimeter and corner joints. Its ±30% movement capability easily handles the differential movement between the tiles and glass screen. The powerful anti-fungal agent provides certainty against mould growth, while the distinctive matt finish blends seamlessly with matt-finish tiles and tapware for a flawless architectural look.
Best Practice Note
For sharp, clean lines, mask both sides of the joint with painter's tape. Tool the sealant off within 5-10 minutes of application and remove the tape immediately while the sealant is still wet for a perfect edge.
For Plumbers & Cabinet Makers: Kitchen & Laundry Fit-Outs
The Professional's Challenge
Sealing around a new sink on a laminated benchtop and along a tiled splashback, requiring a sealant that is waterproof, mould-resistant, non-corrosive, and safe for a food preparation area.
The Adheseal Solution
Matt Seal S-250 is ideal. It is safe for food preparation areas once cured and provides excellent adhesion to both the laminated bench and the glazed tiles. The neutral cure chemistry ensures it won't damage the benchtop or metal sink, and its anti-fungal properties keep the area hygienic and easy to clean.
Best Practice Note
When sealing a benchtop, ensure a continuous bead is applied and tooled to shed water effectively. Pay close attention to corners and tap bases to ensure no voids are left for water to penetrate.
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
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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.
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