What is ST Silicon used for?

ST Silicon is a neutral-cure, non-staining silicone sealant designed specifically for sensitive natural stones (marble, limestone, granite) and stone-look porcelain where conventional silicones can cause edge staining.

Will ST Silicon stain my stone?

No. ST Silicon is independently tested as non-staining on sensitive natural stones, making it the safe choice for marble, limestone, and other porous stone finishes.

Is ST Silicon mildew resistant?

Yes. ST Silicon contains a fungicide that resists mildew and mould growth in wet areas including showers, bathrooms, and around sinks.

Is ST Silicon suitable for wet areas?

Yes. ST Silicon is suitable for perimeter joints in showers, baths, and kitchens. It remains flexible and waterproof for the life of the joint.

What movement does ST Silicon accommodate?

ST Silicon accommodates up to plus or minus 25% joint movement, making it suitable for perimeter and expansion joints in tiled installations.

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Ardex ST Silicone

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Neutral cure silicone for natural stone. Won't stain, water resistant, works with ARDEX waterproofing membranes.

ARDEX ST is a neutral curing silicone sealant built for sensitive natural stone such as marble, sandstone and granite. Its formula is free of the ingredients in most silicones that cause staining, and it contains fungicides to fight mould. Once cured it forms a permanently elastic, water resistant seal that takes up to 20% joint movement.

Where to use it

Movement joints between tiles, corners, and connecting joints to bench tops, bath edges, cupboards and splashbacks
Bathrooms, showers and kitchens
Natural stone wall and floor tiling in living areas, balconies, patios and facades
Joints that will be immersed, such as swimming pools
Bond breaker with ARDEX waterproofing membranes

Why waterproofers buy it

Free of the standard ingredients that stain natural stone
Contains fungicides to combat mould growth
Water resistant once cured, handles up to 20% of the original joint width
Suitable for use with all ARDEX waterproofing membranes
Resistant to UV, common cleaners and disinfectants
Skin forms in 10 to 12 minutes, cures at approximately 1mm per day, 6mm per week
Misty Grey, Ultrawhite, Charred Ash, Alabaster, Slate Grey, Travertine and Clear

Coverage

310mL cartridge: 12 lineal m at a 5 x 5mm joint, 3 lineal m at 10 x 10mm, 1.5 lineal m at 20 x 10mm, 0.7 lineal m at 30 x 15mm.

Not for

Painting over or load bearing construction. Not suitable with bitumen and tar due to discolouration, or polyethylene, butyl, EPDM, rubber, neoprene and Teflon due to lack of adhesion. It is water resistant but not a waterproofing membrane, so the rules of undertile waterproofing still apply.

Skin forming and curing times at 23ºC and 50% RH.

Non staining - free of the ingredients that stain natural stone

Suitable for use with all ARDEX waterproofing membranes

Water resistant - suitable for showers and underwater joints such as swimming pools

Colour: Misty Grey

Quantity: 1

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Ardex ST Silicone

Misty Grey

The Waterproofing Shop

Pickup available, usually ready in 24 hours

22/872 Canterbury Road
Roselands NSW 2196
Australia

+61280213517

Product Details

Advantages:

Superior adhesion: Ensures a secure and durable bond, delivering long-lasting results.

Effortless application: Easy to apply and smooth, saving time and effort during installation.

Anti-mould properties: Contains special inhibitors to prevent the growth of unsightly mould.

Non-corrosive: Safely used on various surfaces without causing damage or discoloration.

Where it can be used:

Sensitive natural stones: Ideal for protecting and sealing delicate stones, preserving their beauty.

Immersed applications: Suitable for swimming pools, water features, and other submerged areas.

Bathrooms and kitchens: Perfect for sealing joints and gaps in wet areas, ensuring a waterproof seal.

HVAC systems: Can be used to seal gaps and joints in heating, ventilation, and air conditioning installations.

Choose ARDEX ST for its exceptional performance and remarkable versatility. With its unique formulation, this silicone sealant guarantees optimal results in various applications while providing the utmost protection against mould growth.

How to Use

Trim the nozzle to the correct bead width, gun a steady continuous bead with good contact on both sides of the joint, then tool off with a silicone applicator before a skin forms at approximately 10 minutesConfirm joints and surfaces are firm, sound, dry, clean and free from grease, oil, dirt, soap and old paints
Run a trial application on painted surfaces and plastic substrates before starting
Where the silicone will contact copper or brass, confirm air is able to circulate
Set the joint at a 2:1 width to depth ratio where possible, minimum 5mm wide and deep internally and 10mm externally, maximum 30mm wide and 15mm deep
Use a backing rod for joints greater than 10mm deep
On flat joints use a polyethylene tape or release agent to prevent three sided adhesion so the silicone is fixed to two surfaces only
Mask the joint edges with tape to avoid getting silicone on the tile or stone and to give a neater finish
Trim the end of the nozzle to obtain the correct bead width and place the cartridge in an applicator gun
Apply at temperatures between 5C and 40C
Apply the sealant in a steady continuous bead, ensuring good contact with both sides of the joint
Tool off with a silicone applicator to finish the joint smoothly before a skin forms, approximately 10 minutes
Clean off any excess while the silicone is still wet
Remove the masking tape while the sealant is still wet
Allow to cure at approximately 1mm per day, 6mm per week
Clean the joint and surrounding surfaces regularly with detergents and disinfectants to maintain the antifungal agent

Technical Specifications

Product Type: Neutral cure silicone sealant
Colours: Travertine, Clear, Slate Grey, Alabaster, Sand Beige, Charred Ash, Misty Grey, Ultrawhite
Form: Coloured paste silicone
Raw Material: Neutral curing system
Joint Width: Up to 30mm wall; up to 15mm floor*
Minimum Joint Size: 5mm wide and 5mm deep internal; 10mm external
Maximum Joint Size: 30mm wide and 15mm deep
Joint Ratio: 2:1 width to depth where possible
Movement Accommodation: Up to 20% of the original joint width
Floor Joints and Stair Treads: Suitable from 12-15mm
Skin Forming Time: 10 - 12 minutes at 23C and 50% RH*
Curing Time: approx. 1mm per day, 6mm per week at 23C and 50% RH*
Application Temperature: 5C to 40C
Underfloor Heating: Yes*
Coverage: 12 lineal m per cartridge at a 5 x 5mm joint; 3 lineal m at 10 x 10mm; 1.5 lineal m at 20 x 10mm; 0.7 lineal m at 30 x 15mm
VOC: Low VOC content, meets Green Building Council of Australia Green Star IEQ-13 requirements
Pack Size: 310mL plastic cartridge
Shelf Life: 15 months in the original unopened packaging, in a dry place at 23C and 50% relative humidity
Hazard Classification: Hazardous chemical, non-dangerous goods; signal word Warning; causes serious eye irritation; no Poisons Schedule
* Values published by ARDEX under Application Properties at 23C and 50% RH

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Technical overview

ARDEX ST is a neutral curing silicone sealant for sensitive natural stone. Its formula is free of the standard ingredients present in acetic and most neutral cure silicones that can cause staining of stone, and it contains antifungal agents to combat mould growth. Cured, it forms a permanently elastic, water resistant seal that accommodates movement up to 20% of the original joint width and resists UV, common cleaners and disinfectants. Being neutral cure it suits all ARDEX waterproofing membranes and can be used in underwater joints such as swimming pools. It has low VOC content and meets the Green Building Council of Australia Green Star IEQ-13 requirements. The data sheet claims no Australian Standard classification and publishes no accredited test report.

View full technical data sheet

Key applications

Movement joints between tiles
Corners in tiled walls and floors
Connecting joints between tiled surfaces and bench tops, bath edges, cupboards and splashbacks
Bathrooms, showers and kitchens
Doors, windows and fixtures
Natural stone wall and floor tiling in living areas, balconies, patios and facades
Joints that will be immersed, such as swimming pools
Bond breaker with ARDEX waterproofing membranes
Floor joints and stair treads from 12-15mm

Surface suitability

Moisture sensitive natural stone prone to staining, such as marble, gneiss, granite, sandstone and limestone
Glazed and unglazed tiles
Enamel
Laminated kitchen benches
Aluminium
Concrete
Glass
Porcelain
Waterproofing membranes (all ARDEX waterproofing membranes)
Wood
Sanitary acrylics
Copper or brass (only where air is able to circulate)
Painted surfaces and plastic substrates (trial application recommended)
Joints and surfaces must be firm, sound, dry, clean and free from grease, oil, dirt, soap and old paints

ARDEX ST is water resistant, however the rules of undertile waterproofing must still be maintained - it is not a waterproofing membrane. It is not suitable for painting over or for load bearing construction. It is not suitable for use with bitumen and tar due to discolouration, or with polyethylene, butyl, EPDM, rubber, neoprene and Teflon due to lack of adhesion, and discolouration may occur in contact with bituminous substrates. Bituminous, tar, oil or acrylic impregnated fillers must not be used. A trial application is recommended on painted surfaces and plastic substrates. Where the silicone is applied to copper or brass surfaces, ensure that air is able to circulate. Natural stone varies greatly by quarry and by position within a quarry. Apply only between 5C and 40C. Bond the silicone to two surfaces only, using polyethylene tape or a release agent on flat joints to prevent three sided adhesion. Regular cleaning of the joint and surrounding surfaces with detergents and disinfectants is needed to maintain the antifungal agent. Classified a hazardous chemical, non-dangerous goods; signal word Warning: causes serious eye irritation. Wear protective gloves, clothing, face and eye protection and ensure adequate ventilation.

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Technical Specifications

Product Type	Neutral cure silicone sealant
Colours	Travertine, Clear, Slate Grey, Alabaster, Sand Beige, Charred Ash, Misty Grey, Ultrawhite
Form	Coloured paste silicone
Raw Material	Neutral curing system
Joint Width	Up to 30mm wall; up to 15mm floor*
Minimum Joint Size	5mm wide and 5mm deep internal; 10mm external
Maximum Joint Size	30mm wide and 15mm deep
Joint Ratio	2:1 width to depth where possible
Movement Accommodation	Up to 20% of the original joint width
Floor Joints and Stair Treads	Suitable from 12-15mm
Skin Forming Time	10 - 12 minutes at 23C and 50% RH*
Curing Time	approx. 1mm per day, 6mm per week at 23C and 50% RH*
Application Temperature	5C to 40C
Underfloor Heating	Yes*
Coverage	12 lineal m per cartridge at a 5 x 5mm joint; 3 lineal m at 10 x 10mm; 1.5 lineal m at 20 x 10mm; 0.7 lineal m at 30 x 15mm
VOC	Low VOC content, meets Green Building Council of Australia Green Star IEQ-13 requirements
Pack Size	310mL plastic cartridge
Shelf Life	15 months in the original unopened packaging, in a dry place at 23C and 50% relative humidity
Hazard Classification	Hazardous chemical, non-dangerous goods; signal word Warning; causes serious eye irritation; no Poisons Schedule
* Values published by ARDEX under Application Properties at 23C and 50% RH

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Frequently asked questions

View all FAQs

What is ST Silicon used for?

Compatibility
ST Silicon is a neutral-cure, non-staining silicone sealant designed specifically for sensitive natural stones (marble, limestone, granite) and stone-look porcelain where conventional silicones can cause edge staining.
Will ST Silicon stain my stone?

Performance
No. ST Silicon is independently tested as non-staining on sensitive natural stones, making it the safe choice for marble, limestone, and other porous stone finishes.
Is ST Silicon mildew resistant?

Installation
Yes. ST Silicon contains a fungicide that resists mildew and mould growth in wet areas including showers, bathrooms, and around sinks.
Is ST Silicon suitable for wet areas?

Compliance
Yes. ST Silicon is suitable for perimeter joints in showers, baths, and kitchens. It remains flexible and waterproof for the life of the joint.
What movement does ST Silicon accommodate?

Performance
ST Silicon accommodates up to plus or minus 25% joint movement, making it suitable for perimeter and expansion joints in tiled installations.

Why trade professionals choose Ardex

Ardex is a global leader in high-performance building products, trusted by Australian trade professionals. The range spans liquid and sheet waterproofing membranes, primers, sealers, screeds and repair systems, engineered for lasting results on residential and commercial projects.

Shop all Ardex