Solutions
Wood and walls that survive Indian monsoon, sun, and salt.
Validated by
DIN 18550·EN 1062-3·ift Rosenheim·WESSLING
The pain — diagnosed
In Mumbai by August, the new wooden deck has black streaks. By the next March, the lime-plastered facade has peeling sheets. By the third monsoon, the cedar shutters have cracked at every joint. The wood and the wall are sound — the failure is in the layer on top of them.
What the substrate endures
Monsoon
8-12 weeks of horizontal rain at 85%+ humidity. Surface temperature drops; substrate stays warm. Vapour pressure pushes water under any sealed film.
Summer UV
Index 9-11 for four months across most of India. Plastic films chalk, oxidise, and microcrack year after year.
Salt aerosol
Coastal sites receive 50-200 mg/m² of NaCl deposited weekly. Salt is hygroscopic; it draws moisture into every microcrack it finds.
Diurnal cycling
Hill stations swing 35 °C by day to 8 °C at night. The substrate flexes; the film does not flex enough and lets go at the bond line.
Film-forming coatings — acrylic emulsion on walls, polyurethane on wood — seal the substrate from the room side. Vapour rising from below cannot escape upward through the film. It condenses behind the film. The bond fails from the inside. By the time the bubble or the crack appears, the wood or the wall has already absorbed weeks of trapped water.
The cycle
bubble → scrape → repaint → bubble. Twelve to eighteen months between repaints in the worst monsoon zones.
The mechanism
Mechanism · 01
LEINOS 150, 236, and 260 are linseed-oil-based. They soak into the wood pores and cure inside the wood — not on top of it. There is no separate film to crack, peel, or trap moisture. The surface greys naturally as a thin oxidised layer; the oil-saturated wood underneath stays sound for years.
Mechanism · 02
LEINOS 622 primer and 665 lime paint stay open-pored after curing. Water-vapour transmission is an order of magnitude higher than acrylic emulsion. Monsoon vapour passes through the wall to the room air, where ventilation handles it. The bond line never gets wet from behind.
Mechanism · 03
Slaked lime in 665 reacts with atmospheric CO₂ to form calcium carbonate — the mineral limestone is made of. The surface hardens with age, not softens. New limewash bonds chemically with the previous coat as both continue to carbonate. Heritage buildings have used this mechanism for two thousand years.
Open-pore impregnation primer with IPBC sapstain barrier — for untreated softwood and absorbent hardwood before LEINOS varnish or glaze topcoats.
View productPenetrating oil-resin finish for exterior wood, designed for terraces, decking, and outdoor timber.
View productPenetrating oil-resin treatment for tropical hardwood furniture and weathered exterior timber — refreshable without sanding.
View productOpen-pore wood stain for timber facades, cladding, windows, and doors — vapour-permeable.
View productAlso in this hub: Mineral Plaster Primer (622) · Lime Paint (665)
Application
For wood: sand to bare timber, brush off dust, allow to reach moisture content below 18%. For lime/mineral walls: remove any existing film coating mechanically, expose sound substrate, dampen surface lightly before priming.
Wood: flood-coat 150 sealer or thinned 236 stain; wipe excess after 20 minutes so oil enters the grain, not just the surface. Walls: apply 622 mineral primer with a brush, working into the substrate; allow 24 hours.
Wood: two coats of 236 stain or 260 oil with 24 hour intervals. Walls: two coats of 665 lime paint with 12-24 hour intervals; mist the wall lightly between coats in dry weather to support carbonation.
Wood: inspect after one monsoon; spot-refresh any sun-bleached or salt-exposed zones with a single thin coat over a cleaned surface. Walls: allow the full carbonation cycle (6-12 months) before any repair patching.
Per-product TDS sheets are the authoritative source for coverage, drying intervals, and tool selection. Use these steps as the system-level shape, then download the relevant TDS from each product page.
Lab evidence
Independent labs, named standards, batch-traceable certificates.
Breathable plaster
Water permeability
Weather cycling
Independent lab
Compare
Conventional path
What fails
Film seals the wall. Monsoon vapour gets trapped behind it. Bond fails inside-out. Bubbling appears within 18-36 months. Biocide leaches; mould returns.
With LEINOS instead
Why it holds
622 primer + 665 lime paint — open-pored, chemically lime-bonded to the substrate, hardens through carbonation over years instead of degrading.
Conventional path
What fails
UV chalks the film; salt cracks it; water enters cracks; wood greys under an intact-looking film. Refresh requires full sanding back to bare timber.
With LEINOS instead
Why it holds
236 stain / 260 oil / 150 sealer — penetrate the wood, no film to fail. Refresh is a single thin coat over a cleaned surface, no sanding needed.
Conventional path
What fails
Biocide leaches out within 18-24 months. Mould returns. The paint itself becomes mould food once the biocide is spent. Repaint cycle repeats with rising biocide load indoors.
With LEINOS instead
Why it holds
665 lime — pH 12+ naturally suppresses spores. No biocide added, no biocide to leach, no re-bloom cycle. Mineral chemistry, not chemical suppression.
Specifier questions
Yes — LEINOS 236 wood stain or 260 wood oil, applied in 2-3 coats, gives 3-5 year exterior durability on hardwoods like teak. Refresh interval is shorter (12-18 months) on softwoods like cedar. Refresh is single-coat oil over a cleaned surface — no sanding required.
No — wood and mineral substrates need different chemistry. Wood takes penetrating linseed oils (236, 260). Mineral walls take the 622 primer + 665 lime paint system. They share a philosophy (breathable, no film, naturally weathered) but the binder is different.
Yes — 665 is mineral with no biocides and no VOC. Rainwater runoff is mildly alkaline (lime) but not toxic; it dilutes harmlessly. The 665 is documented under DIN 18550 breathable plaster standards, and the lime carbonation chemistry is a natural antimicrobial.
