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Bio-Wash Moss Remover
Stop the moss, Stop the damage!
Bio-Wash Moss Remover is a deeply penetrating, aqueous biocidal solution, formulated specifically to target the problem of damaging moss and mould growth on a variety of external mineral surfaces, including walls and paving.
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 for water-seal, masonry paint and paving resins.
Bio-Wash Moss Remover is sometimes equated to “weed killer”, but this is an error as the biocide you need to kill a dandelion is completely different to that needed to eradicate moss. Nevertheless Bio-Wash Moss Remover is a synergistic “broad spectrum biocide” which means it simultaneously targets, kills moss and a whole lot more, including; green mould, black mould, lichens and algae.
• Removal of moss, algae and lichens from external walls & paving
• Cleanses: concrete, brickwork, cement mortar joints, man-made paving, concrete blocks
• Tarmac driveways, paths and roadways
• Sandstone walls, limestone, slate & granite
• Halts the deterioration of mortar joints, caused by invasive moss
• Restores the colour of organically stained brickwork and stone
• Improves adhesion quality of decorative coatings
How does it work?
As with so many aspects of property maintenance, “a stitch in time” really does “save nine” when it comes to controlling moss and mould growth.
Moss, mould and algae are persistent and often destructive house guests, as they all contribute to either decorative or physical deterioration, of the surface to which they have attached themselves.
Left unchecked in mortar joints for example, moss breaks down the mortar in two ways:
a) Chloride erosion
The root system of the moss gradually loosens the surface and the organism retains moisture up to 16 times its dry weight, so that the mortar joints take much longer to dry out. Additionally, this semi-permanent moisture encourages the emergence of corrosive salts which are naturally present in the damp mortar and adjacent brick or stonework. These salts are corrosive to mortar and accelerate the erosion of mortar joints, which might otherwise have survived for decades.
b) Freeze/thaw erosion
In winter the moisture laden moss freezes along with the moisture it has trapped in the mortar joints underneath. This has the effect of rupturing the surface of the mortar joint as the freezing water expands to form ice, which in turn permits deeper water penetration, worsening frost cracks and ultimately leading to complete failure of the mortar joint.
Used as an annual maintenance treatment, Bio-Wash Moss Remover prevents moss from building up to concentrations that can damage buildings and hard landscaping. It can be spray applied with a low-pressure pump sprayer, just as used for garden weed spraying, which allows very large areas to be treated in a short space of time. This approach is highly recommended for tarmac and paved areas with low traffic or under tree canopy where green mould in particular thrives.
However, it is more commonly used as a pre-treatment to remove organic materials including moss, mould and lichens from stone walls, brickwork and paving in preparation for:
• Water-seal or surface water repellent coating on walls
• Re-pointing of weathered and organically contaminated masonry
• Re-rendering of earth-retaining walls
• Re-decoration with masonry paint
• Refinishing paving with a resin sealer
In all of the above scenarios, correct application of Bio-Wash Moss Remover improves adhesion and longevity of the protective treatment or repair, by effectively sanitising the surface. It enhances the substrate stability and in that sense is an absolutely essential part of the preparation required to make the paint, resin, mortar or water seal, bond to the substrate. Nobody wants to see lichen or moss de-laminating a costly paint finish, 6 months after application!
How to use
No preparation is necessary but make sure that the surfaces to be treated are fairly dry and free from “ponding” water or puddles.
For paved or tarmac areas, if there are weeds (broadleaf/grass) as well as moss, these should be sprayed first with a premium grade weed-killer as directed.
Bio-Wash Moss Remover 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 mortar.
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 Moss Remover into the pressure washer soap reservoir for application under pressure.
b) As an effective moss & mould treatment (without pressure washing)
For very heavily moss or mould contaminated surfaces which cannot be pressure washed, e.g. asbestos cement roof sheets, friable sandstone walls, soft bricks etc.
Apply liberally over the entire area by brush or low-pressure spray (not atomiser) and leave for 7 days 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 is approximately two average U.K driveways.
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 Moss Remover into the pressure washer soap reservoir for application under pressure.
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.
Kingfisher Bio-Wash is a deep penetrating, broad spectrum biocide (of a category sometimes described as fungicidal
wash), designed to give quick and efficient removal of all moss, green mould, algae or lichen from a wide range of
outdoor, mineral based surfaces such as walls, paving, patios, roofs and driveways. 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.
Bio-Wash is easy to use and an essential pre-treatment, prior to the application of any of the Kingfisher range of
masonry water seal, paving resin, roof coating and masonry paint. It is available in either READY TO USE or
Companion / Related Products:
• Kingfisher Kolourseal
• Kingfisher Asbestos Roof Coating
• Kingfisher K-Seal, Restore-A-Drive, Ultimate Topcoat, Imprintseal, Blockstar, Indian Sandstone Sealer
• Kingfisher Extreme Climate, Stormseal, Superseal
• Kingfisher Weatherflex
• Kingfisher Coloured Pointing Mortar
• Kingfisher Eco-brick Cleaner
Refer to these individual product data sheets for detailed application guidance published on our website
To eradicate damaging moss and other organic matter from, and also to retard its re-growth onto, the following
• Concrete & Clay Roof Tiles
• Asbestos cement roof sheet
• Slate roofs
Product Data Sheet / Product code 72 REV03 13.12.2021
• Sandstone & Limestone
• Concrete paths & yards
• Paving including: man-made flags, blocks and natural stone
• Wall both brick & stone
• Mortar joints
If in doubt, please call our technical services department on 01229 869 100 for guidance.
• Ease of application by brush or low-pressure spray (non-atomising)
• Versatile application
• No rinsing required
• Kills the moss and mould spores/roots which weed-killers do not
Hard surface biocides are increasingly used in conjunction with powered pressure washers in both commercial and
domestic settings, to clean or prepare surfaces for various types of decorative or protective coating. In that sense
therefore Kingfisher Bio-Wash is THE surface preparation! Often no preparation is necessary, providing the surfaces
to be treated are fairly dry and free from “ponding” water.
For paved or tarmac areas, if there are weeds(broadleaf/grass) as well as moss, these should be sprayed first with
a premium grade weed killer as directed.
Asbestos cement roofs contaminated with moss are often at significant height above ground and should typically
be surveyed by a competent industrial roofing professional before treatment. They can be fragile and require nondestructive cleaning methods (precludes pressure washing), as well as the expertise to identify potential structural
issues and establish safe working protocols including access for the surface preparation phase.
The concentrate should be diluted 1 part Kingfisher Bio-Wash with 4 parts clean water. Also available as Ready to
Use. Apply using a brush or a low-pressure pump sprayer (typical garden weed sprayer) and ensure thorough
a. As a Surface Neutraliser (after pressure washing): Even through pressure washing leaves microscopic roots and
spores within the substrate, joints and crevices, which can rapidly re-grow if unchecked. Liberally apply Kingfisher
Bio-Wash by brush or low-pressure spray (not atomiser) to thoroughly sanitise the surface as a pre-treatment for
subsequent application of the appropriate Kingfisher surface coating. DO NOT RINSE OFF. Leave until the Bio-Wash
has dried in or for a minimum of 1 to 2 hours before subsequent coating.
b. As an Aggressive Moss & Mould Inhibitor (without pressure-washing): For very heavily moss or mould
contaminated surfaces, which cannot be pressure washed, e.g asbestos cement roof sheets, soft sandstone walls,
soft bricks etc. Apply liberally over the entire area by brush or low-pressure spray (not atomiser) and leave to
activate or at least 7 days before brushing scraping or soft hosing the surface clean. NOTE: If scraping dead moss
from asbestos cement roof sheets, ensure the surface is damped with water to prevent fibre release and wear the
recommended PPE for WORKING WITH ASBESTOS, including gloves, face mask and coveralls.
DO NOT apply at air or surface temperatures below +6°C.
Product Data Sheet / Product code 72 REV03 13.12.2021
There are some situations where a surface has been contaminated for a protracted period of time and this can
result in deep staining of the substrate. Some lichens for example will resist even powerful pressure washing with
turbo or rotary jet nozzles. In such cases we recommend contacting our technical services department as there are
too many variations to list here.
Brushes and sprayers can be cleaned in warm soapy water.
5 litres of Concentrate treats: 125 sq.m (when diluted with 20 litres of clean water)
1 litre of Concentrate treats: 25 sq.m (when diluted with 4 litres of clean water)
5 litres of Ready to Use treats: 25 sq.m
25 litres of Ready to Use treats: 125 sq.m
Kingfisher Bio-Wash is supplied in 5 & 25 litre plastic containers
SHELF LIFE & STORAGE
The product has a shelf life of 12 months unopened from the date of manufacture, subject to correct storage
conditions. Store upright in original sealed packaging in a cool dry place, out of direct sunlight Keep out of reach of
a) Whilst Kingfisher Bio Wash is not a weed-killer, in very dry conditions it may temporarily burn or discolour grass
& broadleaf vegetation. Take care to avoid overspray when treating paths or driveways adjacent to lawns. A simple
protection is to lay a broad plank of wood along the grass edge to catch the overspray.
b) Avoid contact with metal or anodised finishes.
c) This class of biocides relies upon U V light activation. You will achieve more consistent results with spring/summer
application than in winter.
d) Never load Bio-Wash into the pressure washer soap reservoir for application under pressure.
HEALTH & SAFETY
This product is classified as an irritant and users should avoid splashing when handling the product and wear
appropriate protective clothing, impervious glove and eye protection during application. Inc case of contact with
skin or eyes rinse the affected area immediately with copious amounts of clean water. Repeated/prolonged contact
with the skin may cause sensitisation. Should irritation persist seek medical attention. Keep children and pets away
from treated area until the Bio Wash has fully dried.
• If applying by spray wear a face mask, disposable gloves and coveralls
• Avoid contact with skin and eyes
• If contact occurs wash immediately with plenty of water
• Keep out of reach of children
• Ensure good ventilation during application and drying
• Always dispose of empty packaging responsibly
This product is non-flammable
Product Data Sheet / Product code 72 REV03 13.12.2021
Before using this product read the Material Safety Data Sheet which can be obtained at
by calling the Kingfisher Technical Dept. Tel: 01229 869 100.
The information given in this product data sheet is given in good faith, based on current knowledge and experience.
It relates only to the specific material designated and may not be valid for such material used in combination with
any other materials or in any process. Such information is to the best of the company’s knowledge and belief,
accurate as of the date indicated.
All recommendations are made without warranty or guarantee, as to accuracy, reliability, completeness since the
conditions of use are beyond our control. It is the user’s responsibility to satisfy themselves as to the suitability and
application of such information for their own use
Used this product for a number of years. Highly effective.
Reviewed by Michael Richards
Worked very well on my garden shed despite raining an hour later
Reviewed by Mrs S A Martin