Paints & Textures · Sri Lanka
Cracked, weathered exterior render doesn't just look tired — it lets heat and moisture into the building fabric. Mapeflex Therm RP is a cement-free, fibre-reinforced, highly elastic heat insulation wall coating that C&S Projects applies to restore cracked or uneven exterior walls before a final heat-reflective topcoat — giving Colombo buildings crack repair and genuine thermal insulation in one process.
The system
Applied in two coats with a special reinforcing net between the layers, Mapeflex Therm RP bonds strongly to old but well-adhered painted walls, skimming mortars and traditional render, with a bonding strength of 2.05 N/mm². Its fibre reinforcement and elasticity let it bridge existing surface cracks and equalise imperfections left by old plaster — without needing full render removal.
It also carries a Euroclass A2-S1-D0 reaction-to-fire classification and requires no curing period, which keeps project timelines shorter than traditional wet-render repair.
The sequence matters. Once this base coat is applied, a premium three-coat silicon-based, waterproof, elastic, heat-reflective paint system goes over it as the final finish. Therefore the insulation and crack repair happen at base-coat stage, while the heat reflective waterproof paint above delivers the weatherproofing and reflective performance.
Avoiding render removal is the practical win. Traditional render repair means hacking off, re-rendering and waiting weeks to cure. For an occupied apartment block in Colombo that is disruptive and expensive, whereas a bonded base coat keeps residents in place.
The thermal benefit works differently from the reflective topcoat above it. Reflection turns solar energy away at the surface, while an insulating layer slows the heat that does get absorbed from moving through the wall. As a result the two work together rather than duplicating each other.
Moisture is the other reason cracked render matters. Fine cracks draw rainwater into the wall fabric by capillary action, and that trapped moisture then drives further deterioration and interior damp. Sealing and bridging those cracks therefore protects the structure, not just the appearance.
Impact resistance is a practical bonus in shared buildings. Corridor walls and baseboards take trolleys, furniture and daily knocks, and an elastic layer absorbs that contact where a brittle skim would chip.
Fibre reinforcement and elasticity span surface cracks and equalise old plaster imperfections.
Applied in two coats with a net between them, which is what gives long-term crack resistance.
Cement-free and thermally insulating, reducing heat transfer through the wall fabric.
Carries a Euroclass A2-S1-D0 reaction-to-fire classification and needs no curing period.
Where it's applied
It suits buildings where the render has aged rather than failed structurally — the common case in Colombo apartment blocks and older houses. Impact-prone areas such as baseboards and shared corridors benefit too, since the elastic layer absorbs knocks that crack a rigid finish.
Insulation panels and skimming mortars also need a compatible base coat before finishing. Applying a standard render over them risks debonding, whereas a cement-free elastic layer bonds and moves with the panel system beneath it, which protects the insulation investment underneath.
Where a wall needs levelling or genuine structural repair first, our surface preparation range covers those products, and our surface preparation service covers the remedial work before any base coat is applied.
Explore the range
Mapeflex Therm RP sits within our wider paints & textures range — functional coatings, exterior systems, enamels, low-VOC interiors and decorative textures, with application by our own teams.
How we work
C&S Projects assesses the extent of existing cracking and render condition before quoting, since the reinforcing net layer is what gives long-term crack resistance. Application is by trowel, and the manufacturer's overcoat interval of 24–48 hours is followed depending on humidity.
Full completion therefore spans several days rather than a single-coat repaint. However, because no curing period is required, the programme is still materially shorter than hacking off and re-rendering a wall the traditional way.
Access is priced into the programme from the start. Upper elevations need scaffolding or gondola access, and treating that as a separate surprise later is how façade budgets get derailed. Therefore the quotation shows the true installed cost rather than a material rate alone.
We are also honest about limits. Live structural movement — a settling foundation or a genuine structural crack — needs engineering attention, not a flexible coating. As a result some surveys end with us recommending investigation first, and our consultation service covers that assessment.
How it compares
Standard crack fillers patch visible damage but do not address ongoing wall movement, so cracks frequently reopen within a year or two. That is why a repainted wall often looks tired again so quickly.
This system's fibre-reinforced, elastic structure is designed to move with the substrate rather than resist it, giving genuinely long-term crack resistance rather than a cosmetic fix. That is why we specify it as a base coat system for buildings with recurring crack issues, then finish with our silicon exterior paint where reflection is not required.
Local coverage
We restore exterior walls across Colombo and the surrounding suburbs — Rajagiriya, Nugegoda, Battaramulla, Nawala, Dehiwala and Kotte — as well as apartment blocks in Colombo 05 and 07. Because our stores sit on Buthgamuwa Road in Rajagiriya, surveys across Sri Jayawardenepura Kotte are easy to arrange before a monsoon season starts, which is the sensible time to deal with cracking.
Older stock benefits most. Many Colombo buildings from the 1980s and 1990s carry decades of patch repairs and repaints, and the render beneath is uneven rather than unsound. For example, a corridor wall in a 1990s block often needs equalising more than it needs replacing.
Timing matters as well. Because the overcoat interval stretches in humid weather, we plan these programmes for drier windows where possible. As a result the base coat and topcoat both cure properly instead of being rushed between showers.
Having assessed and coated exteriors across the Western Province since 2022, we can usually tell from a survey whether a wall is a coating job or a structural one. Therefore clients get a straight answer before committing budget, rather than a coating quote for a problem that needs an engineer. See our completed projects for context.
Quick answers
It resists reopening far better than filler, because the fibre-reinforced layer and net move with the wall instead of fighting it. Where cracking comes from live structural movement, though, that needs engineering attention first.
No. It is the base coat that restores and insulates. A silicon-based, heat-reflective topcoat system is applied over it to provide the colour, weatherproofing and reflective performance.
Considerably less than re-rendering. There is no curing wait and no hacking off, so residents stay in place. Work is phased elevation by elevation with access agreed with management upfront.
“We had repainted twice and the cracks came back both times. They put the reinforced base coat on first and it has held through two monsoons. No residents had to move out.”
Our work
Premium coatings, repairs and finishes delivered for landmark residential and commercial developments across Colombo and Sri Lanka.
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Visit our showroom at 53/3 Buthgamuwa Road, Rajagiriya, or call to arrange a wall survey. Mon–Sat · 10:30 am – 5:30 pm · Sun closed.
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