Commercial jet washing guide
Can you jet wash a fence?
Yes, for most fence materials. But wood, vinyl, metal and composite fences all have different tolerances for pressure, distance and detergent. Getting it wrong on timber splinters the wood, raises the grain and saturates panels leading to rot and premature failure. This guide covers the correct approach for every fence type.
Fences on commercial premises and domestic properties across London accumulate algae, moss, lichen, weathered timber staining, traffic film and general urban grime over time. Jet washing is often the most efficient way to restore their appearance and remove growth before it causes deterioration of the fence material itself. However, a fence is not a concrete forecourt. Wood, vinyl, metal and composite all behave differently under pressure washing, and the settings that deliver excellent results on one material will cause significant damage on another. Understanding the specific tolerance of each fence type is essential before starting any cleaning programme on a commercial or residential fence.
500 to 800
PSI for softwood fences such as pine, spruce and standard featheredge panels. Lower than most people expect
Along the grain
always wash wood fences along the grain direction, never across it — cross-grain pressure raises fibres and splinters the surface
Treat after
wood fences must be allowed to dry for 48 hours after jet washing before applying any stain, preservative or paint
Inspection before jet washing any fence
Before directing any water at a fence, inspect the structure first. Loose boards, cracked panels, lifting post caps, exposed end grain and any areas where the fence appears to be absorbing water and swelling should all be identified. Jet washing a fence with structural weaknesses can worsen existing damage considerably. Any loose fixings should be retightened, any cracked or split boards should be replaced, and any obvious areas of rot should be removed and replaced before cleaning begins. Protect adjacent plants and soil from runoff, particularly if any detergent is being applied.
By fence materialCorrect jet washing settings by fence type
Softwood timber (pine, spruce, standard featheredge panels)
Use 500 to 800 PSI with a 40-degree wide fan nozzle. Hold the nozzle at least 30 to 45 cm from the surface and always direct the spray along the grain direction. Spraying across the grain raises the wood fibres, creates a rough raised surface and forces water into the wood structure. Apply a wood-specific detergent if the fence is particularly dirty, working it in with a soft brush before rinsing. Cold water only. Allow 48 hours drying time before any paint, stain or treatment is applied.
Hardwood timber (oak, teak, iroko, hardwood close-board)
Hardwoods tolerate modestly higher pressure: 1,000 to 1,300 PSI with a 40-degree nozzle at 30 cm minimum. Still work along the grain direction. Hardwood fences are denser and less prone to grain raising but can still be damaged by concentrated pressure. After cleaning and drying, reapply a hardwood oil or UV-protecting treatment to prevent the characteristic greying that untreated hardwood develops on prolonged weather exposure.
Vinyl and uPVC fencing
Vinyl handles pressure washing well at up to 2,400 PSI with a 40-degree nozzle. It is resistant to grain raising and water ingress. Avoid bleach-based cleaners which can yellow or streak white uPVC over time. A pH-neutral all-purpose cleaner or specialist uPVC cleaner produces the best results. Focus on wipe-clean areas around post caps and rail channels where moss accumulates. Rinse thoroughly to avoid cleaning product residue drying as a film on the surface.
Metal fencing (steel, galvanised, powder-coated)
Metal fences handle medium pressure at 1,500 to 2,000 PSI. Apply TFR or a mild alkaline all-surface cleaner to remove traffic film and general grime before rinsing. Avoid directing the jet into hollow sections of hollow-section metal fencing as trapped water accelerates internal corrosion. After cleaning, inspect for rust spots, areas of chipped powder coating or failing paint and treat any exposed bare metal with a rust inhibitor before repainting.
Composite fencing
Composite fences (wood fibre and plastic polymer combination) are generally cleaned at 1,000 to 1,500 PSI with a wide fan nozzle at 30 cm or more. Always check the manufacturer's cleaning recommendations first as some composite products have surface coatings or finishes that are incompatible with certain cleaning chemicals or higher pressures. Never use hot water on composite fencing as it can distort the panels. Allow to dry before inspecting for any discolouration from cleaning product residue.
What to do after jet washing a wood fence
Jet washing removes the existing weathered surface layer from wood, exposing fresh timber beneath. This is exactly what is needed for a stain or treatment to bond properly. However, the fence must be completely dry before any treatment is applied — a minimum of 48 hours in dry warm weather, and potentially longer in the damp conditions typical of a London autumn or winter. Applying stain or paint over damp wood will cause it to lift, bubble and fail within months. Once the fence is dry, apply a suitable preservative treatment, fence stain or exterior paint appropriate for the timber species to protect it from the weather and significantly extend the period before the next professional clean is needed.
Commercial jet washing London
Fence and boundary cleaning across London by Cloud Nine
Cloud Nine cleans fences and boundary structures of all types across London commercial and residential premises using the correct pressure settings and products for each material. We never use excessive pressure on timber and always advise on post-clean treatment. Contact us for a free quote.
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