Fosroc Thioflex 600 PG (Pouring Grade)
The pouring-grade version of Fosroc’s two-part polysulphide sealant, formulated for horizontal expansion and construction joints in floors, pavements, bridge decks and water-retaining structures.
What is it?
A two-component, self-levelling polysulphide joint sealant (pouring grade) that cures to a tough, rubber-like seal with 25% movement capacity on butt joints.
Where is it used?
Horizontal movement joints only – floor expansion and stress-relief joints, bridge decks, canal linings, reservoir bases and other trafficked or ponded surfaces.
Why use it?
It stays flexible for decades and resists fuels, oils and dilute chemicals, making it a dependable choice where PU or acrylic sealants would fail early.
How is it applied?
Mix the base with the curing-agent sachet, install a bond breaker over a foam backing rod, prime porous surfaces with Fosroc Primer 7, then pour the sealant directly into the joint and tool level.
About Fosroc Thioflex 600 PG (Pouring Grade)
Thioflex 600 PG is the pouring (self-levelling) grade of Fosroc’s long-established Thioflex 600 polysulphide sealant system. Where the gun grade is engineered to stay put on vertical and overhead joints, the pouring grade is deliberately flowable so it can be dispensed straight from the tin into horizontal slots and find its own level. It is supplied as a base with the curing agent in a separate sachet; once the two are combined and mixed, a chemical reaction converts the liquid polymer into a solid, elastic rubber that bonds tenaciously to primed concrete and to metals, glass and stone.
For engineers and contractors working across Delhi NCR and the rest of India, the appeal is proven longevity in demanding service. Polysulphide chemistry has a decades-long track record in civil works, and Thioflex 600 carries recognised approvals including BS 4254 and ASTM C920 Class 25. It is the sealant you reach for on floor joints in warehouses and chemical plants, on bridge and flyover decks, and on the horizontal joints of dams, canals and treatment tanks – anywhere the joint must move repeatedly, shrug off spilled fuel or effluent, and remain watertight long after the contractor has left site.
The technical insight
The performance comes from the polysulphide backbone itself. Liquid polysulphide polymers cure through a chemical (not evaporative) reaction, so the sealant develops its properties uniformly through the full depth of the joint rather than skinning over while staying soft underneath. The cured rubber is genuinely elastic – it recovers its shape after being stretched and compressed – which is why it can safely accommodate 25% of the joint width in movement on a butt joint (and up to 50% on a lap joint) cycle after cycle, per BS 6093. The same sulphur-rich chemistry gives Thioflex 600 its standout resistance to hydrocarbons: petrol, diesel, kerosene, aviation fuels and lubricating oils that swell or dissolve ordinary sealants leave it largely unaffected. Curing is temperature-driven, so it firms up in about a week at 25 C but needs a fortnight at 15 C and four weeks near 5 C – a detail that matters when planning winter or high-altitude work.
Where it is used
- Floor expansion and stress-relief joints in warehouses, factories and car parks
- Bridge, flyover and elevated-deck movement joints on horizontal running surfaces
- Horizontal joints in dams, reservoirs, canals and irrigation channels
- Base and floor joints in sewage and effluent treatment tanks
- Joints in industrial floors exposed to fuel, oil or dilute chemical spillage
- Runway, apron and hardstanding joints where aviation fuel resistance is needed
- Basement and subway slab joints requiring a durable watertight seal
- Narrow horizontal joints under 15 mm, gun-applied from a Fosroc ‘G’ Gun
Key advantages
- Self-levelling flow lets it be poured straight into horizontal joints and finish flat
- Accommodates 25% joint movement (50% on lap joints) with genuine elastic recovery
- Outstanding resistance to petrol, diesel, kerosene, aviation fuels and lubricating oils
- Meets recognised international standards – BS 4254, ASTM C920 Class 25, TT-S-00227E
- Bonds firmly to primed concrete plus metals, glass and stainless steel
- Cures uniformly through full joint depth via chemical reaction, not surface drying
- Proven long service life in properly designed and installed joints
- 100% solids with no shrinkage on cure, so the seal profile stays as tooled
Limitations & considerations
- Strictly a horizontal-joint product – use the Thioflex 600 GG gun grade for vertical, inclined or overhead joints
- Not suitable for contact with potable (drinking) water – specify Nitoseal MS600 instead
- Not resistant to chlorinated solvents, aromatic solvents or dilute oxidising acids
- Must not touch pitch- or bitumen-based materials, which can stain and soften it
- Slow to cure in cold conditions – roughly four weeks at 5 C versus one week at 25 C
- Over-painting is not recommended, as paint films crack over a moving joint
Selection & best practice
Success depends on joint design and preparation, not just the sealant. Design the slot to a 2:1 width-to-depth ratio for cyclically moving joints, respecting the minimum sealant depths (10 mm on porous surfaces, 20 mm for trafficked or hydrostatically loaded joints). Surfaces must be dry, clean and frost-free – wire brush, grind or grit blast off all laitance, dust and curing compound. Fit a closed-cell polyethylene backing rod (Hydrocell or Expandafoam) to control depth and act as a bond breaker; where a foam filler is absent, use bond-breaker tape so the sealant bonds only to the two joint faces. Always prime porous surfaces with Fosroc Primer 7 and apply the sealant while the primer is tack-free (re-prime if more than three hours elapse). Mix the full base and sachet together with a slow-speed paddle for the stated time, pour within the two-hour pot life, and tool to a smooth finish. Keep application between 5 C and 50 C and protect fresh joints from water until fully cured.
Specifications
| Product type | Two-part, pouring (self-levelling) grade polysulphide sealant |
| Standards compliance | BS 4254:1983; ASTM C920-87 Type M, Grade NS, Class 25; US Fed. Spec. TT-S-00227E; DTp Highway Works clause 1017 |
| Movement accommodation factor | 25% on butt joints, 50% on lap joints (per BS 6093) |
| Joint width range | 5 mm to 50 mm (pour directly; gun-apply if under 15 mm) |
| Pot life / setting time | 2 hours pot life at 25 C; sets in 18 hrs at 25 C, 36 hrs at 15 C, 72 hrs at 5 C |
| Full cure time | 1 week at 25 C, 2 weeks at 15 C, 4 weeks at 5 C |
| Application / service temperature | Apply 5 C to 50 C; operating range -20 C to +60 C |
| Colour / hardness | Grey; Shore A hardness 15-23 (pouring grade) |
| Pack size | 5 litre tin with curing agent supplied in a sachet inside the tin |
Industry use cases
Industrial & warehouse flooring
Seals floor expansion and stress-relief joints in factories, warehouses and multi-storey car parks where forklift traffic and occasional oil or fuel spillage demand a tough, chemically resistant joint.
Bridges & infrastructure
Handles the repeated thermal and traffic-induced movement on horizontal deck joints of bridges, flyovers and elevated corridors while resisting fuel drips from vehicles.
Water & irrigation structures
Provides a durable watertight seal on horizontal joints in dams, reservoirs, canals and irrigation channels (non-potable), fully cured before permanent immersion.
Sewage & effluent treatment
Withstands dilute acids, alkalis and biologically active effluent in the base and floor joints of treatment tanks and channels at STPs and industrial ETPs.
Airports & fuel-exposed pavements
Its resistance to aviation fuel, diesel and kerosene suits horizontal joints on aprons, hardstandings and fuel-handling areas where hydrocarbon exposure is routine.
Frequently asked questions
What is the difference between Thioflex 600 PG and GG?
How much Thioflex 600 PG do I need per joint?
Do I have to use a primer?
Can Thioflex 600 PG be used with drinking water?
How long before the joint can take water or traffic?
Does it need a backing rod and bond breaker?
How we position Fosroc Thioflex 600 PG (Pouring Grade)
Choose Thioflex 600 PG when the joint is horizontal and needs proven polysulphide durability against fuel, oil and dilute chemicals. For the same performance on vertical, inclined or overhead joints, switch to its sibling Thioflex 600 GG (gun grade). Where a joint carries potable water, Fosroc directs you to Nitoseal MS600 – a low-modulus MS-polymer sealant – rather than a polysulphide. For heavy-duty trafficked expansion joints that need a nosing and armouring rather than a simple sealant, look at Fosroc’s Nitoflor and expansion-joint systems. Within our wider catalogue, comparable polysulphide and PU joint sealants from Sika (Sikaflex range) and STP can also suit specific approvals or budgets – our technical team can match the sealant to your standard, joint movement and exposure.
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