Fosroc Nitoseal SC600
One-part, gun-applied, non-sag joint sealant engineered for expansion and construction joints exposed to strong acids, alkalis, chlorinated water and biological attack.
What is it?
A single-component, moisture-curing, gun-grade (non-sag) joint sealant from Fosroc that uses a specialised polymer chemistry to deliver outstanding resistance to aggressive chemicals while remaining flexible enough to absorb cyclic joint movement.
Where is it used?
Movement and construction joints in chemical bund areas, effluent and sewage treatment tanks, swimming pools, food/wine/citrus processing floors, and concrete exposed to acid spillage or chlorinated water.
Why use it?
It combines broad chemical and biological resistance with genuine elastomeric movement capability (around +/-25%), so a single sealant survives both the chemical exposure and the thermal/structural cycling that would degrade a standard polyurethane or polysulphide.
How is it applied?
Joints are cleaned and dried, faced with a bond-breaker/backer rod to control depth, primed with Fosroc Primer 13, then SC600 is gun-extruded from a 600 ml sausage and tooled within about 20 minutes to a controlled width-to-depth profile.
About Fosroc Nitoseal SC600
Fosroc Nitoseal SC600 is a one-part, gun-applied joint sealant built for a specific and demanding job: sealing moving joints that also have to live in chemically aggressive surroundings. Most general-purpose construction sealants are forced to choose between movement capability and chemical durability. SC600 is formulated around a specialised polymer that cures by reaction with atmospheric moisture to form a tough, flexible, elastomeric seal, and that cured film resists attack from the majority of aggressive chemicals encountered in the food, mining, water-treatment and chemical-processing industries. For Indian contractors and consultants, this means one product can be specified across a water-retaining structure, an effluent plant or a chemical bund, instead of juggling several incompatible sealant systems. It is supplied ready to use in 600 ml foil sausages, with no on-site mixing, batching or proportioning, which removes a common source of site error and waste. Because it is a non-sag grade, it holds its shape in vertical and overhead joints as well as horizontal floor joints. SC600 is independently relevant to potable-water work as well: the cured sealant is tested to comply with AS/NZS 4020 for products in contact with drinking water, making it a defensible choice for reservoirs, water-retaining tanks and treatment works where the sealant is in long-term contact with the stored water. It is distinct from Fosroc’s MS-polymer and polysulphide ranges in that its headline benefit is chemical and biological resistance rather than general weatherproofing, and Space Arc Engineering positions it accordingly – as a specialist sealant for the joints other sealants fail in.
The technical insight
The defining property of SC600 is that it pairs elastomeric movement with chemical durability in a single moisture-cure chemistry. The cured sealant carries a Shore A hardness of approximately 32 (+/-5), which is soft enough to keep stresses on the joint arrises low while still resisting indentation and trafficking on floors. It accommodates roughly +/-25% of joint movement, so a correctly designed 20 mm joint can absorb about +/-5 mm of cyclic expansion and contraction. The practical key is joint geometry: Fosroc specifies an optimum width-to-depth ratio of about 2:1 for moving joints, overridden by minimum sealant depths of 10 mm on non-porous substrates, 12 mm on porous substrates such as concrete and masonry, and 15 mm where the joint is subject to hydrostatic pressure. Cure proceeds at roughly 3 mm in the first 24 hours and around 1 mm per day thereafter at 25 degrees C / 65% RH, which is a meaningful planning factor on deep joints – a 15 mm seal is not fully cured for several days and should be protected from immersion or chemical contact until it is. The cured seal performs across a wide service window of about -50 degrees C to 150 degrees C. Priming with Fosroc Primer 13 is integral, not optional, for durable adhesion; SC600 must be applied while the primer is still within its working window (apply within roughly 8 hours of the primer becoming touch-dry).
Where it is used
- Expansion and construction joints in concrete water-retaining structures (reservoirs, clear-water tanks, sumps)
- Floor and movement joints in chemical processing plants and chemical bund / containment areas
- Concrete joints exposed to acid or alkali spillage
- Sewage and effluent treatment tanks and channels subject to biological attack
- Swimming pools and balance tanks (resistant to pool chlorine, salt-water chlorination and ozone treatment)
- Food, beverage, wine, dairy and citrus processing floors where hygiene and chemical wash-downs apply
- Potable-water structures where the sealant must comply with drinking-water contact requirements (AS/NZS 4020)
Key advantages
- One-part, ready-to-use – no on-site mixing, proportioning or pot-life management
- Broad chemical resistance to strong acids and alkalis encountered in processing and treatment plants
- Highly resistant to biological attack, making it suitable for sewers and effluent works
- Resistant to pool chlorine, salt-water chlorination and ozone treatment
- Tested to comply with AS/NZS 4020 for contact with potable water
- Fast rate of cure for reduced back-to-service times versus many two-part systems
- Gun-grade non-sag consistency works in vertical, overhead and floor joints
- Tough, flexible cured seal accommodating roughly +/-25% joint movement
- Long-life UV and weathering resistance
- Wide service temperature range (approx. -50 degrees C to 150 degrees C)
Limitations & considerations
- Not designed to resist organic solvents – confirm the specific chemical exposure against Fosroc’s resistance data before specifying
- Requires priming with Fosroc Primer 13 for durable adhesion; skipping the primer risks bond failure
- Limited colour range (typically Concrete Grey, Pool Blue and White) compared with decorative facade sealants
- Deep joints cure slowly (about 1 mm/day after the first 24 hours), so full chemical/immersion service must be delayed until cure is complete
- Joint design is critical – incorrect width-to-depth ratio or insufficient depth leads to premature sealant failure
- Supplied only in 600 ml sausages, so large-volume floor-joint works need careful material planning
- As a chemical-resistance specialist it is more costly than general-purpose joint sealants and is over-specified for ordinary external movement joints
Selection & best practice
Design the joint before you order the sealant. Aim for an optimum width-to-depth ratio of about 2:1 for moving joints, but never go below the minimum sealant depths: 10 mm on non-porous substrates, 12 mm on porous substrates such as concrete and masonry, and 15 mm where the joint is under hydrostatic pressure. Keep joint widths within the usable 8 mm to 50 mm range. Control the depth and create a bond-breaker with a closed-cell polyethylene backer rod (or bond-breaker tape on shallow joints) so the sealant adheres only to the two joint faces, not the base – three-sided adhesion is the most common cause of cohesive splitting. Saw, grind or wire-brush the joint arrises to sound, clean, dry concrete and remove laitance, dust and curing-compound residue. Prime both faces with Fosroc Primer 13 and apply SC600 while the primer is still within its open time (within about 8 hours of touch-dry). Gun the sealant from the bottom of the joint upward to avoid trapping air, then tool firmly within roughly 20 minutes to consolidate the seal and wet out both faces. Protect deep joints from immersion and chemical contact until fully cured. Always check the actual chemical(s), concentration and temperature against Fosroc’s chemical-resistance schedule, and remember SC600 is not intended for organic-solvent exposure.
Specifications
| Product type | One-part, gun-applied, non-sag joint sealant |
| Chemistry / cure | Specialised moisture-curing polymer (cures by reaction with atmospheric moisture) |
| Grade | Gun-grade (non-sag) – vertical, overhead and floor joints |
| Movement accommodation | Approx. +/-25% of joint width |
| Shore A hardness | 32 +/- 5 |
| Service temperature | -50 degrees C to 150 degrees C |
| Usable joint width | 8 mm to 50 mm |
| Width-to-depth ratio (moving joints) | Approx. 2:1 (optimum) |
| Minimum sealant depth | 10 mm non-porous; 12 mm porous (concrete/masonry); 15 mm under hydrostatic pressure |
| Cure rate | ~3 mm in 24 h, then ~1 mm/day at 25 degrees C / 65% RH |
| Tooling time | ~20 minutes at 25 degrees C / 65% RH |
| Primer | Fosroc Primer 13 (apply sealant within ~8 h of primer touch-dry) |
| Colours | Concrete Grey, Pool Blue, White |
| Pack size | 600 ml foil sausage |
| Potable-water compliance | Tested to comply with AS/NZS 4020 (products in contact with potable water) |
| Chemical resistance | Strong acids and alkalis, pool/salt-water chlorine, ozone, biological attack (not organic solvents) |
Industry use cases
Water & Wastewater
Sealing expansion and construction joints in sewage treatment tanks, effluent channels and reservoirs where the sealant faces both biological attack and long-term water contact (AS/NZS 4020 compliant).
Chemical Processing & Bunds
Floor and movement joints in chemical plants and secondary-containment bund areas exposed to acid/alkali spillage, where standard polyurethane or polysulphide sealants would degrade.
Swimming Pools & Aquatics
Joints in pool shells and balance tanks that must withstand continuous chlorine, salt-water chlorination and ozone treatment without embrittling.
Food, Beverage & Dairy
Hygienic floor and movement joints in food, wine, dairy and citrus processing areas subject to acidic wash-downs and frequent cleaning chemicals.
Infrastructure & Industrial Floors
Trafficked floor joints in industrial facilities needing a tough, chemically durable, movement-accommodating seal across a wide temperature range.
Frequently asked questions
What type of sealant is Fosroc Nitoseal SC600?
Does Nitoseal SC600 need a primer?
How much movement can SC600 accommodate?
Is Nitoseal SC600 safe for potable water and pools?
What is the correct joint design for SC600?
What are the limitations of Nitoseal SC600?
How we position Fosroc Nitoseal SC600
Within Fosroc’s joint-sealant range, Nitoseal SC600 is the chemical-and-biological-resistance specialist rather than a general-purpose sealant. For routine external movement and construction joints, Fosroc’s MS-polymer sealants (the Nitoseal MS series, e.g. MS600) and polysulphide options such as Thioflex 600 are the standard, more economical choices, while two-part cold-applied or hot-poured systems such as Colpor 200PF suit heavily trafficked pavement and carriageway joints. SC600 earns its place specifically where the joint is exposed to strong acids/alkalis, chlorinated or ozone-treated water, effluent or biological attack – and where AS/NZS 4020 potable-water contact compliance matters. Among credible alternatives an Indian specifier may evaluate, Sika’s Sikaflex range and chemically resistant Sikadur/Sikaflex grades, BASF/MBCC MasterSeal joint sealants, and Pidilite/STP joint-sealing systems cover overlapping ground; the right pick depends on the exact chemical schedule, movement class and water-contact requirement. Space Arc Engineering, as an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, can review the joint design, chemical exposure and movement class with you and recommend whether SC600, a Nitoseal MS grade, Thioflex 600 or a competitor system is the most cost-effective fit before you commit to a specification.
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