The problem on site
Few site issues cause as much friction between clients, main contractors, and finishing teams as white salt blooms appearing on newly finished external walls. On projects across India, external cement plaster often develops powdery white patches, crusts, or streaks shortly after the monsoon or following seasonal changes in temperature. Site teams typically respond by dry brushing the surface, washing it down, and applying fresh coats of primer and exterior paint.
Within weeks, the white deposit reappears. As the crystalline deposits expand beneath the paint film, the finish blisters, flakes, and peels away. Repainting over the affected area without addressing the movement of moisture simply traps the salt layer temporarily. The cycle repeats, leading to repeated rectification costs, site delays, and disputes over plastering quality and paint specifications.
Why it happens
The appearance of white powder on masonry is efflorescence. It requires three conditions: soluble salts within the wall assembly, moisture to dissolve those salts, and a transport path that allows the salt-laden moisture to migrate to an evaporation surface.
In Indian building practices, soluble salts are commonly present in red clay bricks, concrete blocks, sand, or unwashed aggregate, as well as within the Portland cement matrix itself. In some cases, site mixing water containing high dissolved solids contributes additional salt content. When external masonry or render is dry, these salts remain inert within the pore structure.
When external walls are exposed to driving rain, rainwater penetrates the porous plaster and masonry substrate. This water dissolves the free salts, primarily calcium, sodium, and potassium sulphates or carbonates. As weather conditions change and ambient heat warms the wall, capillary action draws the moisture toward the exterior surface to evaporate. When the water evaporates into the air, it leaves the solid salts behind at the surface. If an impermeable paint film is present, the crystals form behind the film, creating subflorescence that shears the paint away from the plaster substrate.
How Space Arc Engineering approaches it
Treating recurrent efflorescence requires stopping liquid water ingress while preserving the ability of the substrate to release internal moisture vapour. Applying an impermeable barrier coat often worsens the problem by trapping existing moisture inside the brickwork, forcing it to travel sideways toward interior living areas or pushing off decorative finishes under vapour pressure.
Space Arc Engineering acts as a technical solution provider and distributor for specialist construction chemicals. Rather than recommending superficial paint touch-ups, Space Arc Engineering evaluates the complete building envelope. Our technical team works with project managers, site engineers, and contractors to locate how moisture is entering the masonry. Common entry points include driving rain absorption across porous render, unsealed window perimeters, cracked parapets, and capillary absorption through poorly detailed copings.
Once moisture pathways are identified and structural defects addressed, Space Arc Engineering supplies high-performance hydrophobic impregnations that stop rainwater absorption without creating a vapour barrier.
The system we supply
To provide a reliable efflorescence on walls treatment, Space Arc Engineering supplies Fosroc Nitocote SN522, manufactured by Fosroc. As an authorised project distributor, Space Arc Engineering delivers factory-fresh material directly to commercial, residential, and infrastructure sites.
Fosroc Nitocote SN522 is a colourless silane-siloxane water repellent formulated specifically for plastered, rendered, and porous masonry substrates. Unlike conventional film-forming sealers or acrylic paints, silane-siloxane treatments do not form a skin on the surface. Instead, the material penetrates deeply into the capillary pores of the plaster and masonry.
Within the substrate, the active silane and siloxane components react with atmospheric and substrate moisture to line the capillary walls with an invisible hydrophobic network. This reaction delivers distinct technical advantages on site:
- Reduces efflorescence and staining: By preventing wind-driven rain from soaking into the plaster, it eliminates the liquid water needed to dissolve and transport interior salts to the surface.
- Lets the wall breathe: The microscopic pores of the masonry remain open to water vapour. Internal moisture can escape naturally as vapour without pushing off the treatment or causing internal dampness.
- Invisible on the finish: Fosroc Nitocote SN522 does not alter the surface texture, sheen, or natural colour of the plaster, render, or stone, preserving the intended architectural finish.
What to check before you order
Before ordering and applying a silane-siloxane water repellent system on your site, our technical team recommends verifying several site conditions:
- Surface cleaning: Remove all existing efflorescence mechanically using a stiff, dry bristle brush. Do not wash salts away with excess water immediately before treatment, as this drives the salts back into the pores.
- Substrate moisture: The plaster or render must be allowed to dry thoroughly before application. Silane-siloxane relies on capillary absorption to penetrate; water-logged pores prevent the active ingredients from entering the substrate.
- Crack remediation: Inspect the wall for structural or shrinkage cracks. Water repellents line pores but cannot bridge cracks wider than hairline fractures. Fill all visible cracks with appropriate repair mortars or sealants prior to application.
- Substrate porosity: The treatment requires a porous, uncoated mineral surface such as sand-cement plaster, exposed brickwork, or concrete. It cannot be applied over existing film-forming plastic emulsions, oil-based paints, or non-porous glazed surfaces.
- Defect rectification: Ensure external drip moulds, parapet copings, and window sill projections are correctly detailed so standing water does not run continuously over the treated facade.
Talk to our technical team
Space Arc Engineering works alongside site engineers and procurement teams across North India to deliver verified technical solutions for difficult masonry and waterproofing challenges. As an authorised distributor, we supply authentic materials manufactured by industry leaders such as Fosroc, backed by direct technical guidance for site application.
If you are facing persistent salt blooms on your external walls, speak with our technical team to discuss material quantities, surface preparation guidelines, and project specifications. You can review our full range of construction chemical systems by visiting our solutions.
For immediate technical assistance or commercial inquiries, contact Space Arc Engineering directly by telephone at +91 99991 55255 or +91 72900 89007, or visit our website at www.space-arc.in.