GK Pro 5Ltr (Professional use only)

GK Pro is the professional cleaning solution of choice for landscapers, groundsworkers, and property maintenance contractors across the UK. A single 5-litre bottle dilutes to make up to 255 litres of product, treating approximately 1,250m² of outdoor surface, all with no harsh chemicals, no bleach, and no risk of surface damage.

The Professional's Choice for Biological Growth Removal

GK Pro has established itself as the go-to professional patio cleaner, driveway cleaner and roof cleaner for contractors who need consistent, predictable results across a wide range of surfaces and biological loading levels.

Its active ingredient, DDAC (didecyldimethylammonium chloride), is a biocidal compound that targets living cells with precision, eliminating algae, mould, lichen, biofilm, and 99.9% of bacterial matter on contact, while leaving any external hard surface completely unaffected.

Unlike bleach-based cleaners that oxidise, discolour, and degrade surfaces over time, GK Pro contains no bleach, ammonia, acids, or solvents. It will not oxidise metal, damage UPVC windows or seals, or strip paint finishes — it is formulated to only eradicate organic material.

For trade professionals working across varied properties and surface types, this means one product that can be used confidently across an entire job, without needing to assess compatibility surface by surface.

How It Works: Foam, Dwell, Weather

GK Pro uses a natural surfactant cleaning action. Upon application, the product foams vigorously, which is a visible indicator that the surface is receiving complete coverage. The active DDAC chemistry then kills biological matter on contact, with residual activity that continues to inhibit regrowth after the initial treatment.

The removal process works in conjunction with natural weather cycles. UV desiccates dead biological matter, while rainfall progressively removes the powdery residue from the surface. This means that on heavy biological loading, such as thick algae, established lichen and long-standing mould, visible results develop over weeks and months rather than immediately.

This is not a fault in the product: it is the process.

On mild staining, results are often visible within days. On heavier contamination, significant improvement is typically seen within two to three months. In severe cases, the full result may take six to twelve months, but the outcome is predictable, and subsequent maintenance treatments work progressively faster as biological loading reduces.

Extraordinary Surface Versatility

GK Pro is suitable for any hard outdoor substrate. It is one of the most versatile professional driveway cleaners and exterior surface treatments available in the UK, approved for use on:

• Driveways and hard-standing areas: block paving, tarmac, concrete, and resin bound surfaces
• Patios and paths: natural stone, sandstone, limestone, slate, porcelain, and concrete paving
• Render, brick, and masonry: including painted render and external wall finishes
• Roof tiles: clay, concrete, slate, and synthetic tiles (use at half dilution on tiled roofs)
• Decking: timber and composite, removing biofilm that contributes to slippery surfaces
• Solar panels, conservatories, and UPVC: safe on all non-living surfaces
• Fibreglass boats, caravans, and polytunnels
• Canvas, Astroturf, pool surrounds, and non-grass tennis courts
• Historic and sensitive surfaces: including thatch, where the low-pressure application method preserves material integrity
• Outdoor furniture, pots, and painted surfaces: without risk of damage to the paint film

The only surfaces excluded are green and sedum roofs.

Concentrated Formula: Outstanding Value for Trade

Each 5-litre bottle dilutes into 250 litres of product, giving a total of 255 litres ready-to-use solution per bottle. Applied via garden sprayer at standard dilution, this provides coverage of approximately 1,250m², or around 625m² on tiled roofs where a lower dilution is recommended.

Dilution can be adjusted to suit the job. Heavier biological loading benefits from a stronger concentration for faster results. Routine maintenance treatments on previously cleaned surfaces can be applied at lower concentration and still deliver effective results. In warmer weather, lower concentrations are often sufficient; in colder conditions, increasing concentration compensates for reduced dwell effectiveness.

No specialist equipment is required for smaller areas; a standard garden sprayer is sufficient. For larger professional applications, GK Pro is compatible with low-pressure spray rigs and soft-wash systems.

Application Conditions

Apply on a dry, relatively wind-free day when no rain is forecast for at least four to five hours and temperatures are above 5°C and rising. Optimum results are achieved in warmer conditions where evaporation is slow, allowing the product to remain wet on the surface for longer and maximise dwell time.

GK Pro can be applied year-round, though results may be slower in cold weather, but performance is maintained with appropriate concentration adjustment.

Once dry, GK Pro is safe around children and animals. It is plant-safe provided direct spraying onto foliage is avoided, and any overspray should be rinsed with clean water immediately. We recommend watering all plants and areas of grass prior to application, and again after completion.

HSE Approved Biocide: Professional Grade Assurance

GK Pro is licensed under HSE Licence Number 10766 and has been subject to routine HSE inspection confirming the product formulation is as stated. For trade professionals who need to evidence compliance or provide product data to clients, the full Safety Data Sheet (SDS) and dilution chart are available for download below.

Key Features

• Professional-grade DDAC biocide: kills algae, mould, lichen, biofilm, and 99.9% of bacterial matter with residual activity to inhibit regrowth
• Bleach, ammonia, acid, and solvent free: non-oxidising formula that will not damage surfaces, finishes, UPVC, seals, or lead works
• Exceptional dilution ratio: one 5-litre bottle makes 255 litres of product, covering approximately 1,250m²
• Suitable for virtually any hard substrate: from block paving and tarmac driveways to roof tiles, thatch, and fibreglass boats
• Adjustable concentration: increase for heavier loading or cold weather; decrease for routine maintenance cycles
• Low-pressure application: compatible with garden sprayers and soft-wash systems; no water blasting required
• HSE Licence No. 10766: UK-regulated biocidal product with independently verified formulation
• Professional use designation: the strongest cleaner in the GK range, trusted by landscaping, groundsworks, and property maintenance contractors across the UK