Bio-wash Roof Cleaner - Professional Algae & Moss Removal  

Bio-wash Roof Cleaner - Professional Grade Roof Cleaning Solution

Stop the green algae, save the roof!

Bio-Wash Roof Cleaner is a deeply penetrating, aqueous biocidal solution formulated specifically for professional roof cleaning to target the problem of damaging green algae and mould growth on various external mineral surfaces, including manufactured roof tiles, slates, and profile sheeting.

Supplied as a concentrated liquid, one 5-litre container diluted makes 25 litres of ready-to-use roof cleaner, which will treat up to 125 sq m of roof tiles. This roof tile cleaner is easy to use and can be applied as a stand-alone treatment or as a companion pre-treatment before surface repair and coating.

Bio-Wash Roof Cleaner is a synergistic "broad-spectrum biocide" that simultaneously targets moss, as well as a range of other organisms that grow on roofs, including green mould, black mould, lichens, and algae. This professional roof cleaning solution is typically used in conjunction with other cleaning methods, including pressure washing and mechanical removal (such as scraping or scrubbing). For optimal application, we recommend using our Moss & Weed Sprayer 5Ltr for even coverage.

Applications include:

• Neutralising and removal of heavy green algae from concrete roof tiles

• Roof tile cleaning & restoring clay roof tiles

• Surface sanitising after pressure washing roofs

• Cleaning slate roofs for green algae removal, especially north-facing elevations

• Asbestos cement (AC) roof maintenance

• Restores the colour of organically stained roofing materials

• Improves the adhesion quality of waterproof coatings

• Prevents moss regrowth under new coatings

How does it work?

Green algae are a particularly insidious roof invader because they play "the long game", and the damage they inflict can go unnoticed until quite far into the deterioration cycle. A few clumps of moss appearing on a roof might seem innocuous enough, but this little plant has an appetite, and your roof is now its food source!

Once established, it can spread remarkably quickly, especially with the second essential ingredient: moisture. Green algae thrive in our rainy climate and will flourish in damp, shaded conditions. As a result, if you look closely, you will notice that the north elevation of most roofs typically exhibits more organic growth than south-facing surfaces.

The root system of the moss gradually loosens the surface, allowing the organism to retain moisture up to 16 times its dry weight. Additionally, this semi-permanent moisture encourages the emergence of corrosive salts (which might otherwise have remained locked away for years) from concrete tiles, clay tiles, mortar joints and even asbestos cement sheets. The release of these corrosive chlorides further contributes to the porosity of the roof material, weakening it.

Freeze/thaw erosion exacerbates the deterioration of the roof surface. In winter, the moisture-laden moss freezes along with the humidity it has trapped. This has the effect of micro-rupturing the surface of the roof, as the freezing water expands to form ice, which in turn allows deeper water penetration, worsens frost cracks, and eventually renders some roofs completely porous.

Frustratingly, attempting to clean roof surfaces by pressure washing or scraping alone can exacerbate the issue. This apparent paradox arises because: a) Removal of organic growth reveals a degraded, more absorbent surface, b) Simple removal leaves behind spores and roots, invisible to the naked eye.

This is why people observe, "I cleaned my roof, but the moss grew back twice as fast". The process may be likened to cultivating a field for a new crop!

It is therefore helpful to think of the roof cleaning process in terms of kitchen hygiene. You can wipe spilt food with a damp cloth, but if you want to sanitise the surface safely, you also need an anti-bacterial spray. Bio-Wash Roof Cleaner is a surface sanitiser that kills the invisible roots and spores embedded in the porous surface of your roof, suppressing regrowth.

Used as an annual maintenance treatment, this professional roof cleaner prevents green algae from building up to concentrations that can damage a roof.

However, it is more commonly used as a roof cleaning pre-treatment for:

• Kingfisher Kolourseal (Preventing re-growth underneath coating)

• Kingfisher Pointing Solution (Re-pointing of ridge tiles and verges)

• Kingfisher Asbestos sealer and primer

• Kingfisher Asbestos roof coating

• Kingfisher Extreme Climate (re-sealing roof tiles invisibly)

• Liquid Roof Repair Compound for comprehensive roof restoration

In all of the above scenarios, the correct application of Bio-Wash Roof Cleaner improves adhesion and longevity of the protective treatment or repair by effectively sanitising the surface.

How to use

Surface Preparation

No preparation is necessary, but make sure that the roof surface to be treated is relatively dry.

Application

Bio-Wash roof tile cleaner concentrate should be diluted 1 part Bio-Wash with four parts clean water. Apply using a brush or a low-pressure pump sprayer (such as a typical garden weed sprayer) and ensure thorough surface coverage.

There are two ways of using the product:

a) As a surface neutraliser (After pressure washing).

With the growing popularity of and wide access to powered pressure washing equipment, surface biocides are frequently used as a post-cleaning surface sanitiser. Even the most thorough pressure washing leaves microscopic roots and spores within the substrate, joints, and crevices, which can rapidly re-grow into moss or mould if left untreated.

Liberally apply Bio-Wash using a brush or low-pressure pump spray (not an atomiser) to render the surface organically inert as a pre-treatment for subsequent application of the appropriate Kingfisher surface coating or repair.

DO NOT RINSE OFF. Leave until the Bio-Wash has dried or for a minimum of one to two hours before applying the subsequent coating.

Note: NEVER load Bio-Wash Roof Cleaner into the pressure washer soap reservoir for application under pressure.

b) As an effective green algae & mould treatment (without pressure washing)

For very heavily contaminated surfaces with green algae or mould, which cannot be pressure washed, e.g., asbestos-cement roof sheets. Bio-Wash roof cleaner kills the organism, undermining its structural adhesion to the substrate, making it easier to remove heavy accumulations.

Apply liberally over the entire area by brush or low-pressure spray (not atomiser) and leave for 7 days (DO NOT RINSE OFF), before brushing, scraping or soft hosing the surface clean.

DO NOT apply at air or surface temperatures below + 6 °C.

How much will I need?

It depends on the project's size. One 5-litre container will dilute to treat up to 125 sq m, which would generally cover the roof of an average 3-bedroom detached home, offering superior coverage compared to other roof cleaning products on the market.

IMPORTANT!

a) Avoid contact with metal or anodised finishes. b) This class of biocides relies on the activation of UV light. You will therefore achieve more consistent roof tile cleaning results with a spring/summer application than with a winter application. c) Never load Bio-Wash Roof Cleaner into the pressure washer soap reservoir for application under pressure. d) If working at height, always seek the advice of a competent roofing professional or a Health and Safety (H&S) adviser before commencing work.

Technical Support

As always, we recommend that you read the Technical Data Sheet & Safety Data Sheet thoroughly before starting any roof cleaning work. If you have any questions, please don't hesitate to call us for advice. We are here to help.

Two primary delivery options for smaller U.K MAINLAND orders (Typically under 100 Kg):

Standard 3-day service: £6.25 plus VAT (Note: Highlands Postcodes may be up to 5 working days)

Next Working Day*: £13.95 plus VAT (Not available to Highlands Postcodes)
*Excludes weekends and public holidays

Cut-off time for “Next Working Day” orders to be processed is 12:00 noon. Once your goods have been despatched, you will normally receive a confirmatory e-mail with tracking details so that you can check the progress of your order. Details

Bio-wash Roof Cleaner is specifically formulated for the UK climate and is designed to tackle both moss and algae without the harsh chemicals found in traditional roof cleaners. Unlike pressure washing or acidic cleaners, which can damage roof tiles, Bio-wash uses biological action to safely and effectively break down organic growth. Our professional grade formula is trusted by roofing contractors across the UK for its gentle yet powerful cleaning action.

Pressure washing can seriously damage roof tiles, dislodge pointing, and force water under tiles, leading to leaks and costly repairs. Bio-Wash Roof Cleaner eliminates the need for high-pressure cleaning by utilising advanced biocide technology that naturally dissolves moss and algae. Apply Bio-wash, allow it to work for 24-48 hours, then rinse with a gentle garden hose - no pressure washer required and no risk of damage.

Professional roof cleaning services in the UK typically cost £300-800, depending on roof size and condition. Bio-wash Roof Cleaner provides professional results at a fraction of the cost - one 5L container treats up to 50m² and costs significantly less than hiring contractors. Plus, you can re-treat problem areas as needed without scheduling appointments or additional call-out fees.

Bio-wash is designed for both professional contractors and confident DIY users. The product is safe for use when following instructions, requires no special equipment beyond basic safety gear, and comes with clear application guidelines. However, if you\'re uncomfortable working at height or have a particularly steep roof, we recommend hiring a professional who can apply Bio-wash safely for you.

Those black stains are typically caused by algae (Gloeocapsa magma), which feed on the limestone filler in asphalt shingles, or lichen growth on clay or concrete tiles. Bio-wash Roof Cleaner is specifically formulated to break down these organic stains without bleaching or damaging the roof surface. Apply Bio-wash evenly, allowing 24-48 hours for the biological action to take effect, then rinse. Stubborn stains may require a second application to remove.

Unlike temporary roof sprays that only clean the surface, Bio-wash penetrates deep into moss and algae roots, providing longer-lasting results. Many roof sprays contain harsh chemicals that can damage plants below or require frequent reapplication. Bio-wash is biodegradable, effective in a single treatment, and typically provides 2-3 years of protection when applied correctly.

While wet-and-forget products rely on rain and time (often 6-12 months for full results), Bio-wash delivers visible results within 24-48 hours through targeted biological action. Bio-wash is also more concentrated, covering larger areas per container, and works effectively even in dry conditions. For UK weather patterns, Bio-wash provides more predictable and faster results.

Bio-wash utilises advanced biocide technology that targets the cellular structure of moss, algae, and lichen specifically. The active ingredients disrupt the organisms\' ability to photosynthesise and maintain cell walls, causing them to break down and die naturally. This biological approach is gentler on roof materials than steam cleaning while being more thorough than surface-only treatments.

Bio-wash is formulated to be safe for all common UK roofing materials, including clay tiles, concrete tiles, slate, and asphalt shingles. When diluted according to instructions, it won\'t harm gutters, downpipes, or established garden plants. However, we recommend covering delicate plants during application and ensuring that you use the proper dilution rates for your specific roof material.

For comprehensive roof rejuvenation, apply Bio-wash during dry weather (ideally in spring or early autumn), allow the full processing time, and then rinse thoroughly. To prevent regrowth, consider annual maintenance applications in problem areas, ensure proper roof ventilation, and trim overhanging branches that create damp, shaded conditions. Bio-wash treatments typically provide 2-3 years of protection, making it an excellent long-term roof maintenance solution.