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Keraflex Maxi S1: A Technical Overview
Keraflex Maxi S1 is a deformable, high-polymer cement adhesive (ISO 13007-1 C2TE S1) engineered for modern large-format tiles. Its high thixotropy eliminates vertical slip, allowing heavy panels to be set from the top down without spacers. An extended open time (>30 min) and long adjustability (~60 min at 23 °C) give installers the working window needed for precise alignment. On floors, the formulation accommodates up to 15 mm bed thickness to correct unevenness without pre-levelling. Once cured, the system provides high tensile adhesion (initial ~2.6 N/mm²) and S1 deformability to handle thermal cycling and substrate movement, including heated screeds. Pot life exceeds 8 hours; light foot traffic is possible after ~24 hours and full service after ~14 days.
Core Features & Specifications
- Classification: ISO 13007-1 C2TE S1 — improved, slip-resistant, extended open time, deformable adhesive.
- Bed thickness: up to 15 mm on floors — corrects uneven substrates without pre-levelling.
- High thixotropy — no vertical slip on walls, even with large/heavy tiles.
- Extended workability — open time >30 min; adjustability ~60 min at 23 °C.
- Pot life >8 h (23 °C); set to light foot traffic ~24 h; ready for use ~14 days.
- Deformable (S1) — accommodates movement and thermal cycling, incl. heated floors.
- Service temperature: −30 °C to +90 °C — suits Australian climate variations.
- Low VOC contribution — supports Green Star™ outcomes when specified correctly.
- Colours: Grey & White; Packaging: 20 kg; Coverage: ~1.2 kg/m² per mm bed.
The Keraflex Maxi S1 Advantage
- Reliable panel control on walls — high thixotropy keeps large-format porcelain in place without sag.
- Fewer prep steps — thicker bed capability reduces separate levelling passes on uneven floors.
- Installer-friendly timing — generous open/adjustability windows reduce stress and rework.
- System compatibility — designed to work over Mapelastic membranes; pairs with Keracolor/Ultracolor/Kerapoxy grouts and Mapesil AC for movement joints.
- Durability under load — high adhesion and S1 flexibility support heavy-traffic areas.
Proactive Troubleshooting
Scenario: Bonding to gypsum/anhydrite without priming
Potential Outcome: Reduced adhesion, powdery interface, debonding under load.
Adheseal Best Practice: Ensure substrates are dry (≤0.5% moisture), hard and dust-free; prime with Primer G or Mapeprim SP as specified before trowelling the adhesive.
Scenario: Setting large tiles in hot/windy conditions
Potential Outcome: Skinning drastically reduces open time, causing poor wetting and voids.
Adheseal Best Practice: Work in smaller areas, shade/cool surfaces, re-comb if skin forms, and use back-buttering on large tiles to ensure full coverage.
Applications in Practice: Trade Scenarios
For Tilers (On-site Installer): Large-format porcelain on vertical walls
The Professional's Challenge
Preventing slip on heavy 1200×600 mm panels while keeping alignment true and grout joints consistent under time pressure.
The Adheseal Solution: Engineered Certainty in Practice
Use a 10×10 mm notch on sound, plumb walls. Trowel a contact layer, then comb fresh ribs and press panels in with full back-butter to achieve >95% coverage. High thixotropy prevents creep; the extended adjustability (~60 min at 23 °C) supports fine tuning.
Best Practice Note
Stage your spread to match conditions; if a skin forms, re-comb the bed rather than misting with water to avoid anti-adhesion films.
For Builders (Specifier/Supervisor): Floors over heated screeds
The Professional's Challenge
Managing differential movement and thermal cycling without grout cracking or debonding.
The Adheseal Solution: Engineered Certainty in Practice
Specify Keraflex Maxi S1 (S1 deformability) over compliant screeds. Commission heating per standard, then set tiles with full-bed coverage. Grout after 24 h (floors) and allow ~14 days before full service; seal movement joints with Mapesil AC.
Best Practice Note
Use perimeter and intermediate movement joints as per tile layout and traffic class; consider Kerapoxy in chemically aggressive zones.
For Waterproofers/Tilers (System Work): Over Mapelastic membranes
The Professional's Challenge
Bonding large tiles over compliant waterproofing without shearing under load or moisture exposure.
The Adheseal Solution: Engineered Certainty in Practice
Once the Mapelastic membrane cures, trowel Keraflex Maxi S1 with an appropriate notch and back-butter profiled backs. For pools/basins and heavy-duty areas, ensure complete coverage and observe curing windows before immersion or service.
Best Practice Note
Use a larger notch and directional trowelling to collapse ribs; periodically lift a tile to verify coverage.
Frequently Asked Questions
What bed thickness can I achieve on uneven floors?
Up to 15 mm in a single pass on floors. This allows minor levelling while fixing large tiles, reducing separate prep steps and keeping schedules tight. Always verify coverage and compress ribs for solid support.
Does it slip on walls with heavy porcelain panels?
The adhesive is highly thixotropic and rated “T” (no vertical slip), allowing top-down setting without spacer pegs. Use back-buttering and correct notch size to maintain coverage and control.
When can I grout walls and floors?
Walls: 4–8 hours. Floors: ~24 hours, depending on tile size and conditions. Choose Keracolor FF/GG or Ultracolor Plus; for chemical resistance, specify Kerapoxy.
Is it suitable over waterproofing membranes?
Yes—apply over Mapelastic AquaDefense/Smart or Mapegum WPS once cured. Ensure full coverage (back-butter), especially for profiled backs and immersed areas.
What are the application temperature limits?
Apply between +5 °C and +35 °C. Service range is −30 °C to +90 °C. In hot/windy weather, reduce spread size and re-comb if a skin forms.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Large-format porcelain on walls | No vertical slip; extended adjustability for precise alignment | Tilers, Builders |
| Uneven screeds (floor) | Up to 15 mm bed reduces separate levelling steps | Tilers, Builders |
| Heated floors | S1 deformability manages thermal movement | Tilers, Builders |
| Over waterproofing membranes | Compatible system approach with Mapelastic membranes | Waterproofers, Tilers |
| Overlay on existing tiles | High adhesion to stable, properly prepared finishes | Tilers |
Applying Keraflex Maxi S1: Enhanced Protocols & Best Practices
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Mixing
Pour powder into clean water while mixing at low speed; rest 5 min and re-mix to a smooth paste.
Grey
5.6–6.0 L water per 20 kg (28–30%).
White
5.4–5.8 L water per 20 kg (27–29%).
Timing: Pot life >8 h at 23 °C (shorter in hot/dry/windy conditions).Pro Tip: Use a clean bucket and paddle; avoid over-watering which reduces strength. -
Trowelling & Coverage
Key in a contact coat, then comb fresh ribs with a suitable notch. Back-butter large or profiled tiles to achieve ≥95% contact (wet areas/immersed) and ≥80% minimum elsewhere.
Floors (uneven)
Use larger notch; up to 15 mm bed to correct minor irregularities.
Walls (heavy panels)
Exploit high thixotropy; set from top-down without spacers, checking plumb.
Timing: Open time >30 min; adjustability ~60 min at 23 °C.Pro Tip: If a skin forms, re-comb; do not wet the bed—water creates an anti-adhesive film. -
Curing, Grouting & Service
Protect fresh work from rain, frost, and strong sun. Honor movement joints and seal appropriately.
Grouting
Walls 4–8 h; floors ~24 h. Use Keracolor FF/GG, Ultracolor Plus, or Kerapoxy where chemical resistance is required.
Movement Joints
Seal with Mapesil AC; consult for heavy-traffic joint design.
Timing: Light foot traffic ~24 h; ready for use ~14 days.Pro Tip: Lift a tile periodically to verify coverage and collapse of ribs, especially over membranes.
Limitations & Safety
Product Limitations
Not for wood/wood-based boards, metals, rubber, PVC or linoleum. Use a system adhesive designed for those substrates.
Avoid moisture-sensitive or stain-prone stones. Confirm stability/compatibility, or select an alternative system adhesive.
Do not expose fresh installations to rain/running water for ~24 h; protect from frost/strong sun for 5–7 days.
Not suitable where immediate trafficking is required. Allow proper curing windows.
Safety & Handling Requirements
Personal Protective Equipment
Cement-containing powder is alkaline when wet. Wear chemical-resistant gloves, eye protection, long sleeves and appropriate footwear. Wash skin after use.
Ventilation Requirements
Provide adequate ventilation in enclosed spaces during mixing and application. Avoid dust generation; use extraction where practical.
Fire & Handling Precautions
Store dry in unopened bags; shelf life ~12 months in cool conditions. Keep away from moisture and incompatible materials.
Emergency First Aid
Eyes:
Rinse cautiously with water for several minutes; remove contact lenses if present and easy; continue rinsing and seek medical attention.
Skin:
Wash with water; remove contaminated clothing and launder before reuse.
Inhaled:
Move to fresh air and rest. Seek medical advice if symptoms persist.
Swallowed:
Rinse mouth; do not induce vomiting; seek medical attention immediately.
Seek medical attention immediately in all cases of serious exposure.
Keraflex Maxi S1 Application Guide
Cementitious Screeds & Renders (incl. heated)
Surface Preparation
Cured, sound, clean, and dry; remove laitance and contaminants. Typical cure: screeds ~28 days; renders ~1 week/cm (unless using special fast-track binders). Honor movement joints.
Primer Requirements
No primer typically required
Prime only if dusty/porous as part of site control.
—Gypsum Board & Anhydrite Screeds
Surface Preparation
Substrate must be perfectly dry (≤0.5% moisture), hard, dust-free. Sand anhydrite skin and vacuum thoroughly.
Primer Requirements
Primer required
Apply a uniform primer coat and allow to dry before trowelling the adhesive.
Primer G or Mapeprim SPExisting Tiles / Marble (Sound)
Surface Preparation
Ensure existing finish is firmly bonded, degreased and abraded if glossy; rinse and dry. Check for hollows and rectify.
Primer Requirements
Primer recommended for optimal adhesion
Use a suitable adhesion promoter where contamination risk is high.
Consult Adheseal for primer optionsWaterproofed Substrates
Surface Preparation
Membrane fully cured and compatible; clean and dry; no ponding. Verify film integrity.
Primer Requirements
No primer typically required
Ensure complete adhesive coverage; back-butter profiled tile backs.
Mapelastic AquaDefense / Smart; Mapegum WPS (substrate systems)Insulation & Acoustic Panels (Spot-Bonding)
Surface Preparation
Flat, clean substrates. Plan spot pattern to suit panel stiffness and weight.
Primer Requirements
Primer optional
Use primer only if substrate is dusty/porous.
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