UltraTech Seal & Dry
Single-component, polymer-modified cementitious waterproof coating — CFTRI-approved for potable water tanks and a dependable workhorse for bathrooms, chhajjas and wet areas. Genuine UltraTech stock with applicator support from Space Arc Engineering, Delhi NCR and Pan-India.
What is it?
A grey, single-component polymer-modified cementitious powder that mixes with plain water into a brushable waterproof slurry for concrete and masonry surfaces.
Where is it used?
Overhead and underground water tanks (including potable), bathrooms, sunken slabs, chhajjas, small terraces, basements and damp-prone external walls.
Why use it?
Resists 5–7 bar water pressure from the positive side, stays breathable so it resists blistering, carries CFTRI approval for drinking-water contact, and needs nothing but water on site.
How is it applied?
Brush or spray applied in two coats of 0.6–0.8 mm each, the second laid perpendicular to the first, over a clean, pre-dampened (saturated surface dry) substrate.
About UltraTech Seal & Dry
UltraTech Seal & Dry is the base grade of UltraTech Cement’s waterproof coating range: a factory-blended powder of cement, selected polymers, graded fillers and sand that becomes a waterproof coating the moment clean water is stirred in. There is no liquid component to pair, no ratio to get wrong at site — a genuine advantage on Indian job sites where a mason, not a chemist, does the mixing. Laid on by brush or spray in two thin coats, it cures into a hard, breathable membrane that bonds tenaciously to concrete, brick and block, and holds back water at pressures of five to seven bar from the water-facing side.
What sets it apart from generic cementitious coatings is its CFTRI approval, which clears it for drinking-water contact — the reason it has become a default choice for coating the inside of overhead and underground tanks in housing societies and institutions. Its resistance to UV, fungus and moss also lets it work on exposed chhajjas and parapets where many coatings chalk and fail. Space Arc Engineering supplies Seal & Dry in 1 kg, 5 kg and 25 kg packs across Delhi NCR and Pan-India, with applicator crews available for tank and wet-area jobs where workmanship decides the outcome.
The technical insight
The chemistry is straightforward but effective. When the powder is mixed with water, cement hydration and polymer film formation happen together: as the cement matrix hardens, dispersed polymer particles coalesce into a continuous film threading through the capillary network. The result is a coating that blocks liquid water — the pores are plugged and lined with hydrophobic polymer — yet remains vapour-permeable, because water vapour molecules can still migrate through. That breathability matters more than most site engineers realise. Moisture trapped behind an impermeable film builds vapour pressure and pops the coating off in blisters; Seal & Dry lets that vapour escape, which is why it holds up on tank interiors and rising-damp-prone walls. The polymer content also gives modest flexibility, enough to bridge static hairline cracks up to 0.5 mm, though not the elongation of a true elastomeric grade.
Where it is used
- Interior coating of overhead and underground potable water tanks (CFTRI-approved for drinking-water contact)
- Bathrooms, toilets and sunken slab portions before brickbat or filler and tiling
- Chhajjas, small balconies and terrace patches exposed to sun and rain
- Positive-side waterproofing of basement and retaining walls
- External walls and parapets suffering dampness and moss growth
- Water-retaining structures such as fountains and utility tanks
- Re-waterproofing of old cementitious surfaces during renovation and society repair work
Key advantages
- Single-component — only water is added at site, so batching errors are practically eliminated
- Withstands 5–7 bar water pressure from the positive side; rated 1.5 bar from the negative side
- CFTRI approval permits use inside drinking-water tanks
- Breathable membrane releases trapped vapour, so it resists blistering and delamination
- UV and infrared resistant — suitable for sun-exposed chhajjas and parapets, unlike many coatings
- Strong bond to concrete, brick and block; applies by ordinary brush or spray equipment
- Non-toxic and resistant to fungus and moss growth
- 1 kg, 5 kg and 25 kg packs suit everything from a single bathroom repair to a full tank contract
Limitations & considerations
- Crack-bridging is limited to about 0.5 mm static cracks — for substrates with live movement, step up to Seal & Dry Flex or Hi-Flex
- It is a rigid-leaning cementitious coating, not an elastomeric membrane; it needs a sound, stable substrate to perform
- The grey cementitious finish needs a protective screed or tiling in trafficked areas — it is not a wearing surface
- Application in direct summer sun needs shading or light misting after about an hour, or the coat dries too fast and weakens
- It waterproofs, but does not repair — cracks, honeycombs and cold joints must be treated before coating
- Negative-side capability (1.5 bar) is modest; always coat the water-facing side wherever access allows
Selection & best practice
Surface preparation decides most failures, so spend the time there: remove laitance, oil, curing compound and loose material; cut open and repair cracks and honeycombs with a polymer-modified mortar; then pre-wet the substrate to a saturated surface dry condition — damp, with no standing water. Mix by adding powder into measured water (never the reverse) using a slow-speed stirrer until the slurry is uniform and lump-free, and mix only what the crew can place within the working time. Apply the first coat by brush or spray at 0.6–0.8 mm, working it into corners, junctions and around pipe penetrations. Allow it to set, then lay the second coat perpendicular to the first for full coverage. Allow roughly 48 hours before overcoating, tiling or screeding. In hot weather, shade the fresh coating or mist it lightly after an hour. For potable tanks, cure fully, then fill, drain and flush before putting the tank into service.
Specifications
| Composition | Single-component, polymer-modified cementitious powder (grey) |
| Coverage | 10–12 sq ft per kg (approx. 1.0–1.1 m² per kg) in two coats |
| Thickness per coat | 0.6–0.8 mm; two coats recommended |
| Positive-side pressure resistance | 5–7 bar |
| Negative-side pressure resistance | 1.5 bar |
| Crack bridging | Up to 0.5 mm (static cracks) |
| Recoat / readiness | Approx. 48 hours before subsequent application |
| Certification | CFTRI-approved for potable water contact |
| Pack sizes | 1 kg, 5 kg and 25 kg |
Industry use cases
Housing societies & RWAs
Recoating overhead and underground tank interiors during annual maintenance — the CFTRI approval satisfies residents and auditors that drinking water stays safe.
Residential developers
Standard specification for bathrooms and sunken slabs across towers, where a one-pack material keeps quality consistent between labour gangs and floors.
Institutions & hospitals
Water tanks, kitchens and wet areas where non-toxicity and fungus resistance matter as much as waterproofing itself.
Commercial & industrial
Positive-side protection of basements, utility tanks and plant-room floors on stable RCC substrates.
Repair & renovation contractors
Small packs and brush application make it practical for chhajja repairs, damp external walls and one-bathroom jobs without mobilising heavy equipment.
Frequently asked questions
Is Seal & Dry actually safe for drinking-water tanks?
How much material should I order for my job?
Seal & Dry, Flex or Hi-Flex — which grade do I need?
Does it need water curing like plaster?
Can tiles be fixed directly over the coating?
Will it hold back water coming from the far side of the wall?
How we position UltraTech Seal & Dry
Seal & Dry is the entry point of UltraTech’s waterproof coating family, and the right pick when the substrate is sound and the budget is tight. Where movement is expected — large terraces, podiums, structures with thermal cycling — step up to UltraTech Seal & Dry Flex or Hi-Flex for real elongation, and pair repairs with UltraTech Seal & Dry SBR as the bonding and mortar-modifying latex. Consultants who prefer a two-component acrylic system with a long infrastructure track record often nominate Fosroc Brushbond, which Space Arc also stocks, so like-for-like comparison across brands is straightforward.
Fosroc Brushbond — Specifiers wanting a two-component acrylic-cementitious coating with a controlled liquid-to-powder ratio and an established record on large water-retaining structures often choose Brushbond over a single-component grade.
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