Description
Green film on a rendered wall is a moisture problem showing a biological symptom, so the order of work decides whether the clean holds: trace the damp, then treat the growth. This concentrate is the treatment step, and it works inside the substrate rather than on top of it.
Where Atlas Mykos Plus 5L Works on UK Facades, Terraces and Basements
Atlas Mykos Plus 5L clears algae, mould, lichen and basidiomycete fungi from rendered facades, terraces and basements under biocide authorisation No 7371/18, applied at 0.02 litres of concentrate per square metre per pass.
Stocked by Renders World within the facade and render cleaning range, it is the option to reach for when a surface-only wash has already been tried and the growth returned. The Atlas sheet is specific about why: the product penetrates a few millimetres into absorbable mineral substrates and acts within the material structure, which is where mycelium sits after a pressure-wash has taken the visible film off.
The sheet lists what it is intended for, and the list is wider than render alone:
- Facades with or without thermal insulation systems, renders, concrete, and cement or cement-lime plasters.
- Rough masonry — brick, hollow brick and blockwork — plus stone, limestone and gravestones.
- Horizontal and enclosed areas: terraces, roofs, basements, floors and screeds, and existing painted coatings.
- Not timber, which the sheet excludes by naming every other building material instead.
Why Trade Buyers Order a Biocide Concentrate Rather Than a Generic Wash
Four things separate this from a bucket of proprietary cleaner, and all four are on the manufacturer's sheet rather than on a shelf label.
- An authorisation number you can quote: biocide marketing authorisation No 7371/18, with the active substances declared as alkyl (C12-16)-dimethylbenzylamine at 2.40 g/100 g and 2-octyl-2H-isothiazol-3-one at 0.24 g/100 g.
- Dilution up to 1:5: the mix is matched to how far the growth has developed, so one container serves a range of jobs as a mould remover for render and adjacent hard surfaces.
- A stated preventive effect: Atlas records that treated surfaces are protected against the development of biological corrosion, which is the part a wash-and-rinse leaves out.
- Finishing work is allowed afterwards: paints, renders and ceramic tiles can go on from 48 hours after the final application, so the treatment sits inside a refurbishment programme rather than beside it.
Figures Taken From the Atlas Mykos Plus Data Sheet
Every value below is transcribed from the English technical data sheet, update date 5 March 2018, linked at the foot of this page.
| Property | Value as the sheet states it |
|---|---|
| Product type | Concentrated fungicide and algaecide, surfactant biocides |
| Biocide authorisation | No 7371/18 |
| Active substances | Alkyl (C12-16)-dimethylbenzylamine 2.40 g/100 g; 2-octyl-2H-isothiazol-3-one 0.24 g/100 g |
| Dilution | Maximum 1:5 with water; smaller ratio for strong growth |
| Consumption | 0.02 l concentrate per m² for a single application |
| Quantified biocidal effect | Min. 150 g/m², against algae and mould |
| Contact time | At least 6–12 hours per application |
| Break between applications | 12–24 hours |
| Before finishing work | Not earlier than 48 hours after application |
| Packaging | Plastic container, 1 l and 5 l |
| Storage | +10°C to +30°C, protect from freezing; 24 months shelf life |
Two of those lines pull in different directions, and reading them together is the practical benefit of having the sheet open. Concentrate consumption of 0.02 l/m² diluted at the maximum 1:5 gives about 0.12 litres of prepared solution per square metre, which — taking the solution at roughly a kilogram per litre, an assumption the sheet does not state — lands under the 150 g/m² at which the sheet places the biocidal effect. Mix richer than 1:5 on developed growth, apply until the surface is genuinely saturated rather than merely damp, and the stricter of the two figures is the one being satisfied.
How to Dilute It and Work Through Three Applications
Atlas recommends applying the product three times, because vegetative mycelium and germinating spores come off easily while resistant spore forms such as conidia do not. Following the full sequence is what makes one visit sufficient.
- Remove the moisture source first. The sheet names the work: reconstructing horizontal or vertical damp proofing, repairing roof flashing, or installing proper ventilation.
- Pre-clean the infected surface. Brush and vacuum limited growth; use mechanical means or a pressure washer where the infection is tough.
- Dilute with water to a maximum of 1:5, stirring the concentrate thoroughly before use, and mixing richer where growth is strongly developed.
- Apply uniformly and profusely by brush, roller or sponge until the surface is completely moist, then leave it for at least 6–12 hours.
- Repeat twice more with 12–24 hours between applications, removing any remaining stains mechanically, for example with water under pressure.
Working out quantity is straightforward from the sheet: 5 l ÷ 0.02 l/m² = 250 m² for a single pass, and 250 m² ÷ 3 applications ≈ 83 m² treated on the full three-pass protocol before allowing for a richer mix. Identifying what is actually growing sharpens that estimate, which is where the difference between red and green algae on rendered walls earns its keep.
Substrate Limits, Indoor Rooms, and the Finish That Follows
Atlas directs several situations to a different product in the same family, and a trial application on a less exposed area is recommended in every case, since it confirms how a particular surface responds before a full elevation is committed.
- Kitchens, bathrooms, laundries, swimming pools and grouts: Atlas recommends ATLAS MYKOS No. 1 for these instead.
- Indoor rooms treated with this product: back in use 48 hours after application, with respiratory protection where ventilation is insufficient.
- Appearance: the sheet states that surface mould and fungal efflorescence are removed without a change of colour, tarnish or gloss.
For the finish afterwards, Atlas recommends silicone or silicate paints — naming ATLAS SALTA N — because they reduce substrate absorptivity and limit the risk of further contamination. On a sound but weathered wall that points to the silicone masonry paints; where the render itself has reached the end of its life, a fresh silicone render goes onto a disinfected substrate instead. Keeping either finish clean afterwards is covered in washing down render without damaging the surface.
Matching the Cleaner to the Stain on a Rendered Wall
Three cleaners sit in this collection and each answers a different chemistry, so the diagnosis comes before the order. Renders World keeps all three so a single visit can carry the right one.
| What is on the wall | Which product | Why |
|---|---|---|
| Algae, mould, lichen, fungi | Atlas Mykos Plus | Authorised biocide, penetrating and preventive |
| Cement, lime or salt residue | Atlas Cement Away SZOP | Formulated for mineral deposits |
| Resin and polymer marks | Resin Away SZOP 2000 | Formulated for organic binder residues |
White bloom is the one most often misread as growth, and treating it as biological wastes a pass; identifying efflorescence and white staining on render separates the two before anything is mixed.
Is This the Right Treatment for Your Elevation?
- A strong fit: algae, mould, lichen or fungal growth on render, insulated facades, terraces, basements or stone, where residual protection against recolonisation is wanted.
- Order a different product: indoor wet rooms and grouts take ATLAS MYKOS No. 1, and timber falls outside the substrate list entirely.
- Sequence it properly: treat before repainting or re-rendering, allowing the 48-hour interval, so the new coat goes over a disinfected wall.
- Deal with the damp first: resolving flashing, drainage or ventilation is what turns a clean into a lasting result, and it is step one on the manufacturer's own sheet.
Pack size, availability and current pricing sit in the order panel on this page; keeping a planned cleaning interval alongside the finish is set out in a maintenance routine for a rendered facade.
FAQ — Quantity, Compatibility and Safe Use
How much surface will a 5 litre container treat?
At the sheet's 0.02 l/m², 5 litres of concentrate covers 250 m² for one application, or roughly 83 m² across the recommended three. Strongly developed growth calls for a richer mix than 1:5, so allow margin on a badly weathered elevation.
Can it be used on render over external wall insulation?
Yes — the sheet names building facades including those of thermal insulation systems, alongside renders, concrete and cement-lime plasters. Two habits keep it predictable:
- Run a trial application on a less exposed part of the elevation first.
- Keep to the dilution and the 6–12 hour contact time rather than raising strength arbitrarily.
How does it differ from the Cement Away cleaner?
They answer opposite problems. This is an authorised biocide for living growth; Cement Away is the product for cement, lime and salt residues. Diagnosing the stain decides which one goes on the order, and the cleaning collection carries both.
How soon can the wall be painted or re-rendered?
Not earlier than 48 hours after the final application. Atlas recommends silicone or silicate paints for the new finish, ATLAS SALTA N among them, since lower substrate absorptivity limits the conditions growth needs.
What precautions does the concentrate need?
Protective gloves, clothing and eye protection are specified, and spillage is collected and disposed of through an authorised company, because the product contains 2-octyl-2H-isothiazol-3-one, may produce an allergic reaction and is very toxic to aquatic life with long-lasting effects. Store it sealed between +10°C and +30°C, away from frost and direct sunlight, and follow the label and safety data sheet in full.
Technical Documentation Behind the Figures on This Page
- ATLAS MYKOS PLUS technical data sheet, English edition — authorisation number, active substances, dilution, consumption, contact times, substrate and room list, storage and shelf life, hazard statements; update date 5 March 2018, and the source of every figure above.