Dr. Fixit Repairite
One bag, two jobs: a polymer-modified cementitious compound that upgrades ordinary plaster into waterproof render and doubles as a patch-repair mortar for spalled concrete and cracked masonry.
What is it?
A single-component, polymer-modified cementitious powder from Dr. Fixit (Pidilite), blending Portland cement, graded fine aggregate and polymer modifiers. It works both as a waterproofing additive for site-mixed plaster and as a standalone repair mortar.
Where is it used?
Rain-exposed external plaster, bathroom and kitchen renders, retaining wall finishes, spalled concrete patches and crack filling from hairline up to 5 mm on buildings across Delhi NCR and pan-India.
Why use it?
The polymer dose is factory-controlled, so every batch of plaster gets consistent water resistance and bond — no site-dosed liquid admixture to get wrong. As a mortar it reaches a minimum 20 MPa at 28 days with 0.8 MPa pull-off bond.
How is it applied?
Blend 1 part Repairite with 3 parts OPC and 12 parts sand by volume for waterproof plaster, or gauge 1:1 with OPC at a 0.25–0.30 water-powder ratio for repair mortar. Trowel-apply onto a prepared, pre-wetted substrate and moist-cure.
About Dr. Fixit Repairite
Most plaster failures on Indian sites trace back to the same two gaps: plain cement-sand render that drinks water through its capillary network, and repair patches that debond because ordinary mortar has poor grip on old concrete. Dr. Fixit Repairite closes both gaps with one material. It is a ready-to-use dry powder in which Portland cement, graded fine aggregate and polymer modifiers arrive pre-blended from the factory, so the polymer content — the ingredient that actually delivers the waterproofing and adhesion — is never left to a helper’s judgement at the mixing platform.
Used as an additive at roughly 1:3:12 with OPC and sand, it converts routine plaster into a dense, low-absorption render for facades, wet areas and retaining walls. Gauged 1:1 with fresh OPC and water, it becomes a trowelable repair mortar for spalled cover concrete and cracks up to 5 mm wide. Space Arc Engineering stocks Repairite in 25 kg bags and supports contractors and consultants with mix guidance, BOQ estimation and trained applicators across Delhi NCR and pan-India.
The technical insight
The chemistry at work is polymer co-matrix formation. As the cement in the mix hydrates, the polymer particles dispersed through the mortar coalesce into a continuous film that interpenetrates the growing network of hydration products. This co-matrix does three things a plain cement-sand mix cannot. First, it plugs and narrows the capillary pores that would otherwise wick rainwater through the render — the source of the lower permeability and reduced absorption. Second, the polymer film acts as an adhesive bridge at the substrate interface, which is why pull-off bond strength holds at a minimum 0.8 MPa instead of the patch simply ringing hollow after a season. Third, the film gives the hardened mortar a measure of internal restraint and flexibility, reducing the plastic and drying shrinkage cracking that plagues site-mixed renders in North Indian summers. Because the polymer is pre-dosed into the powder, this mechanism performs identically bag after bag.
Where it is used
- External waterproof plaster on rain-exposed walls, parapets and facades
- Internal renders in bathrooms, kitchens, utility balconies and other wet areas
- Renders and protective finishes on retaining walls and basement perimeter walls
- Patch repair of spalled and honeycombed cover concrete on columns, beams and slabs
- Filling of static cracks in plaster and masonry, from hairline up to 5 mm width
- Renovation and re-plastering of aged, deteriorated renders during society repairs
- Re-profiling of chipped edges, sills and jambs before painting or texture coating
Key advantages
- Dual-purpose material — one 25 kg bag serves both waterproof plastering and patch repair, simplifying site inventory
- Factory pre-dosed polymer removes the most common site error: inconsistent liquid admixture dosing
- Noticeably lower water permeability and surface absorption than plain cement-sand plaster
- Strong substrate adhesion (minimum 0.8 MPa pull-off), so patches and renders resist hollowing and debonding
- Reduced plastic and drying shrinkage cracking compared with conventional site-mixed render
- Reaches a minimum 20 MPa compressive strength at 28 days in repair-mortar mode — adequate for most cover-concrete patches
- Uses ordinary OPC and local sand, so crews work with familiar tools and methods
Limitations & considerations
- Not a structural-grade repair mortar — for load-bearing repairs to beams, columns or pre-stressed members, specify a fibre-reinforced R3/R4 class product such as Dr. Fixit Repair Polymer Mortar instead
- Crack filling is limited to static cracks up to 5 mm; live or moving cracks need an elastomeric sealant, not a cementitious fill
- It densifies plaster but is not a membrane — roofs, podiums and water-retaining structures under hydrostatic pressure still require a dedicated waterproofing system
- Being cementitious, it demands proper moist curing; skipping curing in hot, dry weather will crack any polymer-modified render
- Performance depends on substrate preparation — applied over laitance, dust or loose plaster, no polymer chemistry will hold
- Published data on this page covers strength and bond only; for project specifications requiring standard compliance certificates, ask Space Arc for current manufacturer documentation
Selection & best practice
Start with the substrate, because that is where these jobs are won. Cut back loose plaster and defective concrete to a sound base, rake out cracks to a clean V, and remove dust, oil and curing-compound residue. Pre-wet the surface to saturated-surface-dry — damp, with no standing water. For waterproof plaster, dry-blend 1 part Repairite with 3 parts OPC and 12 parts clean, well-graded sand by volume before adding water; mixing the powders first is what guarantees an even polymer distribution. For repair work, gauge 1:1 with OPC and hold the water-powder ratio at 0.25–0.30 — resist the urge to over-water for easier trowelling, since excess water is what kills both strength and impermeability. Apply in controlled layers, compact well against the substrate, and close the surface with a wooden float rather than over-polishing with steel. Moist-cure for several days, especially on sun-facing elevations. In peak summer, plaster in the cooler hours and shade fresh work from direct wind and sun.
Specifications
| Form | Single-component polymer-modified cementitious powder |
| Composition | Portland cement, graded fine aggregate, polymer modifiers |
| Mix ratio — plaster additive | 1 : 3 : 12 (Repairite : OPC : sand, by volume) |
| Mix ratio — repair mortar | 1 : 1 (Repairite : OPC) |
| Water-powder ratio (repair mortar) | 0.25 – 0.30 |
| Compressive strength (repair mortar) | Minimum 20 MPa at 28 days |
| Pull-off bond strength | Minimum 0.8 MPa |
| Crack-filling range | Hairline up to 5 mm width |
| Packing | 25 kg bag |
Industry use cases
Housing Societies & Redevelopment
During structural repair programmes in NCR societies, Repairite handles the bulk quantum of work — re-plastering weathered facades in waterproof render and patching spalled chajjas, sills and cover concrete — with one material the contractor already has on site.
Residential Construction
Builders specify it in external plaster and bathroom renders of new villas and floors, getting factory-consistent integral waterproofing without policing admixture dosing across multiple plastering gangs.
Commercial & Institutional Buildings
Schools, hospitals and office buildings use it for wet-area renders and periodic facade renovation, where low absorption keeps paint and texture finishes from peeling off damp plaster.
Industrial Facilities
Plant maintenance teams keep bags on hand for running repairs — cracked wall renders, chipped plinths and minor spalls — where mobilising a full repair-mortar system is not justified.
Infrastructure & Boundary Structures
Retaining walls, compound walls and basement perimeter walls receive Repairite-modified renders to resist the constant moisture exposure that destroys plain cement-sand finishes.
Frequently asked questions
How is Repairite different from adding an SBR liquid like Pidicrete URP to my plaster?
Can Repairite alone stop an active leak?
What are the mixing ratios?
How much area will a 25 kg bag cover?
Is it suitable for structural repairs to beams and columns?
Does polymer-modified plaster still need curing?
How we position Dr. Fixit Repairite
Repairite sits at the general-repair and waterproof-plaster end of the Dr. Fixit range. Within the same family, step up to Dr. Fixit Repair Polymer Mortar or Polymer Mortar HB for structural-grade patching, use Pidicrete URP where a liquid SBR bonding agent or slurry coat is needed, Crack-X Paste for fine surface cracks, and Roofseal or Newcoat where the real problem is roof waterproofing rather than plaster. For consultant-specified structural rehabilitation packages, Space Arc also supplies Fosroc Renderoc and Sika MonoTop repair systems, so the same purchase order can cover both the engineered repair mortar and the Repairite render that finishes the job.
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