Fosroc Brushbond TGP
Crystalline capillary waterproofing that grows inside the concrete — sealing pores and hairline cracks against water pressure from either side, and safe for potable water contact per ANSI/NSF Std 61.
What is it?
A single-component crystalline waterproofing powder from Fosroc (formerly Tegraproof C) — a blend of Portland cement, graded quartz and active chemicals that reacts with free lime inside concrete to grow insoluble, pore-blocking crystals.
Where is it used?
Water tanks and reservoirs, sewage and water treatment plants, basements and foundations, tunnels and manholes, sunken slabs, terraces and balconies — anywhere cementitious substrates face hydrostatic water.
Why use it?
It waterproofs the concrete itself rather than sitting on it, so it resists water from both positive and negative sides, cannot delaminate, and keeps reactivating whenever moisture returns. Chloride-free and NSF 61 compliant for drinking-water structures.
How is it applied?
Mix 3 parts powder to 1 part clean water, brush-apply two coats at 1.0–2.0 kg/m² per coat onto damp, prepared concrete, then moist-cure for 48 hours with fog spraying.
About Fosroc Brushbond TGP
Brushbond TGP takes a fundamentally different route to waterproofing than membranes and coatings. Instead of forming a barrier over the surface, its active chemicals migrate into damp concrete and react with the free lime left over from cement hydration, producing needle-like insoluble crystals within the capillary network. Those crystals choke off the pathways water uses to travel through concrete and fill non-structural hairline cracks up to 0.25 mm wide. Because the treatment becomes part of the concrete, it works whether water pushes from the outside (positive side) or from behind the treated face (negative side) — a decisive advantage for basements and below-ground tanks where external access is impossible.
For Indian water-retaining and wastewater structures, the compliance story matters as much as the mechanism. Brushbond TGP is chloride-free, resists the chemical attack typical of sewage and industrial effluent, and meets ANSI/NSF Std 61 requirements for potable water contact, which lets consultants specify one product across drinking-water tanks and STP structures alike.
The technical insight
The crystalline reaction is moisture-triggered and self-renewing. When water enters the treated zone — during service, not just at application — the residual reactive chemicals reactivate and grow fresh crystals precisely where the leak path is. This is why the system is described as self-sealing for fine shrinkage cracks, and why moist curing is non-negotiable: the TDS requires the applied coating to stay wet for a minimum of 48 hours (fog spraying 3–4 times daily) because crystal formation simply stops without water. Full activation develops over 2–3 weeks after application, so ponding tests scheduled too early can show misleading results. Measured film properties are respectable in their own right — tensile strength above 1.5 N/mm² and adhesion above 1.0 N/mm² — but the real performance sits in the capillary network, not the surface film.
Where it is used
- Underground and overhead water tanks, reservoirs and other water-retaining structures
- Sewage treatment and water treatment plant structures exposed to effluent attack
- Basements, rafts and foundations under positive or negative hydrostatic pressure
- Tunnels, manholes and below-grade utility chambers
- Sunken slabs of toilets and utility areas before finishing
- Roof slabs, terrace gardens, balconies and sunshades
- Repairing hairline cracks, plugging holes and sealing wall–floor junctions
- Industrial and office buildings needing damp-proofing of cementitious surfaces
Key advantages
- Works from both positive and negative sides of hydrostatic pressure — treat basements from inside without external excavation
- Becomes integral to the concrete, so there is no membrane to puncture, blister or delaminate
- Self-seals hairline non-structural cracks up to 0.25 mm as crystals regrow on contact with water
- Meets ANSI/NSF Std 61 for potable water suitability — specifiable for drinking-water tanks
- Chloride-free, protecting embedded reinforcement
- Resists chemical attack from sewage and industrial wastes
- Simple brush application by site labour after standard surface preparation
- Suitable for both internal and external cementitious surfaces
Limitations & considerations
- Seals only non-structural hairline cracks up to 0.25 mm — moving, live or structural cracks need a flexible membrane or injection system instead
- Demands strict moist curing for 48 hours; skipping the fog-spray regime undermines crystal growth and system performance
- Full activation takes 2–3 weeks, so leak testing and water immersion must wait (minimum 7 days air curing before filling)
- Not to be applied when temperature is at 5°C and falling
- Requires a damp, sound, mechanically prepared substrate — water blasting or acid etching adds a preparation step some coatings skip
- Short working window: pot life is 40 minutes, and mixed material should be used within about 20 minutes at 27°C
Selection & best practice
Surface preparation decides the outcome. On old concrete, water-blast to remove laitance, oil and contamination — blasting also leaves the surface saturated, which is exactly the condition Brushbond TGP needs. On new concrete, acid-etch or sand/water-blast after striking formwork so crystals can penetrate. Cut construction joints, cold joints and any static crack wider than 0.25 mm into a V-groove and fill with Brushbond TGP mixed to mortar consistency before coating. For the slurry, add 3 parts powder to 1 part clean potable water and mix with a slow-speed drill and paddle; if it stiffens, re-stir — never add extra water. Batch small: mix only what the gang can place in about 20 minutes at 27°C. Brush on two coats at 1.0–2.0 kg/m² each, then fog-spray the finished work 3–4 times daily for 48 hours, keeping it off foot traffic for 48 hours and heavy traffic for 7 days. Where active leaks are running, stop the water first — polyurethane injection with Fosroc Nitofill UR63 is the standard pre-treatment.
Specifications
| Form | Single-component cementitious powder (Portland cement, quartz aggregate, active chemicals) |
| Mixing ratio | 3 parts powder : 1 part clean water |
| Coverage | 1.0–2.0 kg/m² per coat (brush); typically 2 coats |
| Pot life | 40 minutes (use within ~20 minutes at 27°C, 50% RH) |
| Specific gravity | 1.6–2.0 g/cc |
| Tensile strength | > 1.5 N/mm² |
| Adhesive strength | > 1.0 N/mm² |
| Crack sealing capability | Non-structural hairline cracks up to 0.25 mm |
| Pack size / shelf life | 15 kg bag; 12 months unopened in dry storage |
Industry use cases
Water & Wastewater Infrastructure
STP and WTP tanks, clarifiers and manholes benefit from the system’s resistance to sewage and industrial effluent, with no membrane edge for aggressive water to get behind.
Residential & Commercial Basements
Negative-side capability means occupied basements with rising damp or seepage can be treated from inside, avoiding excavation of the external face.
Drinking Water Storage
ANSI/NSF Std 61 compliance and chloride-free chemistry make it a clean specification for municipal reservoirs, society OHTs and underground sumps.
Tunnels & Below-Grade Utilities
Crystalline treatment handles the persistent hydrostatic heads and inaccessible external faces typical of tunnels, lift pits and utility chambers.
Building Terraces & Sunken Slabs
A thin, brush-applied treatment for roof slabs, terrace gardens and toilet sunken portions before brickbat coba, screed or tile finishes go down.
Frequently asked questions
Can Brushbond TGP stop water coming from behind the wall (negative side)?
Is it safe for drinking-water tanks?
How much material do I need?
Why does the applied coating need to be kept wet?
When can the tank be filled after application?
Will it seal an actively leaking crack?
How we position Fosroc Brushbond TGP
Brushbond TGP is Fosroc’s economical crystalline option: choose it when the substrate is stable and the enemy is capillary seepage or hydrostatic pressure, especially on the negative side. Where the structure moves — exposed terraces with thermal cycling, or slabs with live cracking — a flexible film serves better, and the polymer-modified Fosroc Brushbond membrane is the natural companion specification; the two are often combined, TGP inside the tank and Brushbond on the exposed face. Active leaks call for Fosroc Nitofill UR63 PU injection before any coating work. For projects standardised on other brands, Space Arc also supplies comparable crystalline systems such as Dr. Fixit Krystalline, and our applications team can match a system to your bill of quantities across brands.
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