Applying silicone masonry paint is mostly a sequence of waits: wait for the render to season, wait for the diluted first coat to dry, wait for the weather to sit inside the limits the manufacturer sets. Get those three right and the rest is roller work. This guide follows the ATLAS SALTA technical data sheet dated 6 May 2024, fetched for this update, and covers the two tinting bases Renders World stocks in the silicone masonry paints range — Base White for pale SAH shades, Base Grey for deep ones.
Where Applying Silicone Masonry Paint Begins — Seasoning the Substrate
Applying silicone masonry paint starts with one number from the 2024 Atlas Salta sheet: five days, the minimum a thin-coat mineral render seasons before the first coat goes anywhere near it. Miss that window and colour evenness suffers rather than adhesion, which is why the seasoning table below governs the programme more than any other line on the sheet. Older surfaces get a second clock: the sheet asks for a minimum 48 hours of drying after rainfall stops before painting an old render, and longer as humidity rises.
| Substrate | Minimum seasoning before painting | What sets the wait |
|---|---|---|
| Thin-coat mineral render | 5 days | Above +5 °C and under 65% humidity; slower in poor conditions |
| Thin-coat dispersion render | 7 days | Binder cure rather than moisture loss |
| Traditional mineral plaster | 2–4 weeks | Alkalinity and moisture stabilising |
| Old render, after rain | 48 hours dry weather | Extend the period the higher the air humidity |
Priming is not a required stage here — the sheet states plainly that the substrate does not need priming, because the first coat primes it. That saves a product and a drying day on sound walls. Where a wall is chalky, patched or unevenly absorbent, a consolidating product from the Renders World exterior render primers range is a trade decision taken on the condition of the wall, not a manufacturer requirement, and no consumption figure is quoted for it on this page.
One check belongs before the order, not after delivery. The substrate table on this sheet routes certain surfaces — among them lime and renovation plasters, gypsum finishes, board substrates and some existing paint coatings — to SALTA S, SALTA N or SALTA E instead of the paint sold here. The column alignment in the fetched copy cannot be resolved row by row with certainty, so the mapping is not reproduced; send the substrate description through with the colour code and it gets confirmed against the current Atlas table before anything is tinted.
How to Dilute and Roll the Two Coats
The sheet gives one dilution figure and one recoat interval, and both are tighter than the numbers that circulate in general decorating advice. Follow them and a two-coat elevation fits inside a single daylight window at 20 °C.
- Mix the bucket mechanically first. High-binder paints settle in storage — that sedimentation protects the paint from drying out — so a slow-speed mixer and a paint paddle restore an even consistency. The sheet is explicit that the paint is not combined with any other material.
- Dilute the first coat by 5% — 0.5 litres of clean water per 10-litre bucket — and hold that same ratio across the whole elevation so suction and sheen stay consistent.
- Apply by roller, brush or airless spray. Spray is fully supported: the sheet names a Wagner HC 950 with a 517 nozzle at 150–170 bar, or an HEA 517 nozzle at 100–120 bar, laid on as a thin even film. Sprayed work is undiluted throughout.
- Recoat after about 6 hours at 20 °C and 50% relative humidity, with drying running 2 to 6 hours depending on substrate, temperature and humidity.
- Apply the final coat undiluted, working continuously and planning the breaks in advance — corners, building returns, under downpipes, at colour changes.
Key Takeaway: Two coats, the first diluted with exactly 0.5 litres of water per 10-litre bucket and the second undiluted about six hours later, is the whole method — and in poor weather the sheet allows a third coat to even the surface out, so the honest bucket count for a marginal week is one more than the arithmetic gives.
When to Apply in Cold, Wet or Bright UK Weather
The working envelope is +5 °C to +30 °C with relative humidity under 80%, measured for the paint, the substrate and the surrounding air. Adding ATLAS ESKIMO — named on this sheet as the reduced-temperature additive — extends use down to 0 °C and up to around 80% humidity, which covers most frost-free UK winter days. No dose per bucket is published here, because the Salta sheet states none; take the rate from the Eskimo packaging or confirm it with us before mixing.
- Protect the surface while it dries: the sheet asks for the painted face to be shielded from sun, wind and precipitation during work and through the drying period, which on scaffold means keeping sheeting up rather than dropping it early.
- Fresh render needs sheeting throughout: where a newly rendered facade is being painted, the netting stays on from the start of rendering until 24 hours after painting finishes.
- Uniform drying drives uniform colour: the sheet ties shade consistency directly to how evenly the substrate has dried, so a wall that dries in patches reads in patches.
- Cold-weather rendering has its own rulebook: the render below sets the seasoning clock, and NHBC Standards 2026 — applying to registered homes whose foundations begin on or after 1 January 2026 — updated their Chapter 3.2 guidance on rendering in cold weather in that revision.
How Decorators Keep a Large Elevation Reading Evenly
Most of the difference between a good facade and an acceptable one is batch and break discipline rather than technique. Painting a surface with paint of one production date is the sheet's own instruction, and it matters most on long unbroken walls under raking afternoon light.
- Order the full quantity in one go so every bucket shares a production date, and mix buckets for one elevation together before starting.
- Expect a slight smoothing of the texture: painting naturally levels a render face a little, and coating two areas of differing texture or technical parameters can read as two shades of the same colour.
- Repair before you coat: minor cracks and damage are made good first — the sheet names a fast-setting levelling mortar of the ATLAS ZW 330 type for the job — and old, weakly bonded coatings are removed back to sound material.
- Clean tools with clean water immediately, before the paint dries on them.
- Watch the shelf clock: the paint carries a 12-month usability period from the production date on the pack, so part-used stock from last season is worth checking before it goes on a wall.
Performance-wise, both bases sit on one sheet, so the base choice is a colour decision rather than a technical one. The declared figures are W3 low water permeability, under 0.1 kg/m²·h0,5, against V2 medium vapour transmission, 15 to 150 g/m²·d, with an equivalent air layer Sd of 0.14 m to 1.4 m per coat. Medium is the operative word: rain stays out reliably, and where a wall must remain as vapour-open as physically possible that specification is worth taking deliberately rather than by default. Hiding power is declared as class 2 at an 8 m² yield, film thickness E3, 100 to 200 µm, gloss G3 matt, density 1.42 g/cm³, and the palette runs to 406 SAH colours including six whites.
How Much Paint to Order, and What a Square Metre Costs
Consumption is scoped to the surface, and the sheet's three figures are not interchangeable — the difference between the mineral render row and the smooth plaster row is nearly double. A trial area remains the accurate way to confirm consumption on textured work.
- Thin-coat mineral renders: about 0.25 l/m² per coat, roughly 4.0 m² from one litre.
- Thin-coat dispersion renders: about 0.22 l/m² per coat, roughly 5.0 m² from one litre.
- Smooth plasters: about 0.15 l/m² per coat, roughly 7.0 to 8.0 m² from one litre.
- A 100 m² elevation, two coats on mineral render: 100 m² × 0.25 l × 2 = 50 litres, so five 10-litre buckets, or six once cutting-in and the possible third coat are allowed for.
- The same wall on smooth plaster: 100 m² × 0.15 l × 2 = 30 litres, three buckets.
- A 35 m² semi-detached front elevation on mineral render: 35 m² × 0.25 l × 2 = 17.5 litres, so two buckets.
On price, both tinting bases read £57.50 per 10-litre bucket at the Renders World product endpoints in August 2026; no VAT figure was displayed there, so none is stated here. At 0.25 l/m² per coat one bucket covers 20 m² in two coats, giving £57.50 ÷ 20 m² = £2.88/m² — material only, before labour, access or preparation. Choose the base from the shade: Atlas Salta Base White 10 L for pale and off-white SAH colours, Atlas Salta Base Grey 10 L for charcoal, slate and deep saturated tones. Both sit inside the wider Renders World rendering materials catalogue alongside the renders these paints are specified over.
Two closing points worth carrying into the order. The assessments printed on the sheet — four European Technical Assessments and five ITB national assessments, among them ATLAS ETA-06/0081 and ATLAS ROKER ETA-06/0173 — describe named Atlas ETICS systems that the paint forms a component of, not the bucket standing alone. And the substrate-variant check comes before tinting, since a lime-plastered, gypsum-based, board-faced or previously coated wall may be routed to a different Salta variant. Send the substrate description with the colour code and the Atlas Salta base pairing gets confirmed before mixing.
Written by Mariusz Saja. Technically reviewed by Renders World Team. Last reviewed Aug 2026.
Applying Silicone Masonry Paint — Your Questions Answered
How many buckets does a house elevation need?
Work from the consumption row that matches the surface. On thin-coat mineral render at 0.25 l/m² per coat, a 60 m² elevation in two coats needs 60 × 0.25 × 2 = 30 litres, three 10-litre buckets. On smooth plaster the same wall needs 60 × 0.15 × 2 = 18 litres, two buckets. Add one bucket where the weather is marginal, because the sheet permits a third coat to even the surface out.
Is a primer needed underneath?
Not as a rule — the sheet states that priming is not required, because the first diluted coat primes the substrate. Chalking, powdery or unevenly absorbent walls are a separate judgement, made on the wall itself, and a consolidating product is sensible there. Loose or poorly bonded old coatings come off first either way.
Can it go on in cold or humid weather?
Standard work runs from +5 °C to +30 °C below 80% relative humidity. Adding ATLAS ESKIMO takes the range down to 0 °C and up to about 80% humidity, which keeps a shoulder-season programme moving on frost-free days. Confirm the additive rate from its own packaging, as the Salta sheet gives no dose.
Can it go over an existing painted facade?
Existing paint coatings appear among the substrates on the sheet, and sound, firmly bonded film is a workable base once chalking, flaking and biological growth have been dealt with. Some coated substrates route to another Salta variant, and that routing could not be read off the fetched copy unambiguously — worth confirming with your colour code rather than assuming this base suits every previously painted wall.
What keeps the finish looking good afterwards?
The coating is formulated to resist dirt adhesion — a compact, smooth film that lets settled dust and fungal spores lose their grip and wash off with rain and wind — and to resist algae development. Shaded north elevations still repay an occasional wash, and treating growth early keeps any future recoat to a straightforward paint-on-paint job rather than a strip.
How breathable is the cured film?
Declared at V2, medium vapour transmission between 15 and 150 g/m²·d, with an equivalent air layer Sd of 0.14 m to 1.4 m per coat. That suits render and masonry that needs to release moisture steadily while shedding driven rain at W3. A wall required to stay maximally vapour-open is a specification conversation before the colour is chosen, not after. Both bases share these figures, so the grey base performs as the white one does.
What is the VOC content?
Category A/c/FW with a maximum VOC content of 39.9 g/l against a permitted 40 g/l, so it sits just inside the limit for its category — relevant on occupied buildings and on schemes with environmental reporting attached.