Bio-Wash Roof Cleaner (Green Algae & Mould Inhibitor)  

Bio-wash Roof Cleaner

Stop the green algae, Save the roof!

Bio-Wash Roof Cleaner is a deeply penetrating, aqueous biocidal solution, formulated specifically to target the problem of damaging green algae and mould growth on a variety of 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 cleaner, which will treat up to 125 sq.m.  It is easy to use and can be applied as a stand-alone treatment or as a companion pre-treatment, ahead of surface repair & coating.

Bio-Wash Roof Cleaner is a synergistic “broad spectrum biocide” which means it simultaneously targets and kills moss, plus a whole range of other organisms that grow on roofs, including: green mould, black mould, lichens and algae. It is generally used in concert with other cleaning methods, including pressure washing and mechanical removal (scraping/scrubbing).

Applications include:
•    Neutralising and removal of heavy green algae from concrete roof tiles
•    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 adhesion quality of water-proof coatings
•    Prevents moss re-growth under new coatings

 

How does it work?

Green algae is a particularly insidious roof invader because it very much plays “the long game” and the damage it inflicts can go un-noticed 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 loves our rainy climate and will thrive in damp, shaded conditions which is why, if you look carefully, you will notice that the north elevation of most roofs exhibit more organic growth than south facing surfaces.   

The root system of the moss gradually loosens the surface and the organism retains 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 contributes further to the porosity of the roof material and weakens it.  

Freeze/thaw erosion exacerbates deterioration of the roof surface.  In winter the moisture laden moss freezes along with the moisture 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 permits deeper water penetration, worsening frost cracks and eventually rendering some roofs completely porous.

Frustratingly, cleaning the moss by pressure washing or scraping alone can actually make matters worse.  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, more 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 anti-bacterial spray.   Bio-Wash Roof Cleaner is that surface sanitiser, killing the invisible roots and spores embedded in the porous surface of your roof, suppressing the re-growth.

Used as an annual maintenance treatment, it 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)

In all of the above scenarios, 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 fairly dry.

Application

Bio-Wash Roof Cleaner concentrate should be diluted 1 part Bio-Wash with 4 parts clean water. Apply using brush or low-pressure pump sprayer (typical garden weed sprayer) and ensure thorough surface wetting.

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/mould if left untreated.

Liberally apply Bio-Wash by brush or low-pressure pump spray (not 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 in or for a minimum of one to two hours before 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 green algae or mould contaminated surfaces 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 size of the project.  One 5 litre container will dilute to treat up to 125 sq m which would generally treat the roof of an average 3 bedroom detached home.

IMPORTANT!

a) Avoid contact with metal or anodised finishes.
b) This class of biocides relies on U.V light activation.  You will therefore achieve more consistent results with spring / summer application than in winter.
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 H&S adviser, before commencing works.

 

Technical Support

As always we recommend that you read the Technical Data Sheet & Safety Data Sheet thoroughly before commencing any work.  If in doubt please call us for advice, we are here to help.