Plastic & uPVC Cleaning

Plastic is deceptive. It's non-porous, so contamination sits on the surface and lifts off easily — in principle one of the simplest surfaces we clean. But it's also chemically vulnerable in a way that stone and metal aren't, and the damage from getting it wrong is instant and permanent.

The specific risk is crazing. Certain solvents attack the polymer itself, producing a network of fine cracks in the surface that turn the plastic cloudy and brittle. It happens in seconds, it can't be cleaned or polished out, and the affected panel or section has to be replaced. It's the reason we test on plastic even when the job looks trivial.

Know which plastic you're dealing with

The differences matter because their chemical tolerances aren't the same.

uPVC — windows, doors, fascias, soffits and guttering. Reasonably robust, but strong solvents dull it and abrasives scratch it. Older uPVC that's been in the sun for twenty years develops a chalky, degraded surface layer, which is a different problem from dirt.

Polycarbonate — canopies, shelter panels, rooflights, machine guards. Tough against impact and famously vulnerable to solvents; some products craze it on contact. It also scratches very easily.

Acrylic — signage faces, display panels, some glazing. Even more solvent-sensitive than polycarbonate and scratches at the slightest abrasion.

GRP — kiosks, planters, moulded seating, play equipment. Durable, but the gel coat fades and chalks with UV, and cleaning it back reveals uneven fading rather than fixing it.

How we clean plastic safely

Mildest first, always, and tested on a hidden section — behind a downpipe, under a lip, on the reverse of a panel. On most plastic that means starting with hot water and a soft brush and going no further, because dirt on a non-porous surface generally doesn't need chemistry.

Where graffiti is involved we use plastic-safe removers formulated not to attack the polymer, applied for a short dwell and removed promptly. We don't reach for a general-purpose remover just because it worked on a metal shutter last week — the same product that's routine on powder coating can ruin a polycarbonate panel.

Steam is useful on plastic but needs judgement about distance and dwell. Thin sections can distort with sustained direct heat, so we keep the lance moving and further back than we would on masonry.

• Identify the plastic — uPVC, polycarbonate, acrylic or GRP, and its age and condition
• Test in a concealed area before anything goes on a visible face
• Hot water and soft brush first — often all that's needed
• Plastic-safe removers only, short dwell, removed and rinsed promptly
• Steam with distance, keeping the lance moving on thin sections

Green uPVC and the North West climate

The most common plastic job we do isn't graffiti at all — it's uPVC that has gone green and grey. Fascias, soffits, window frames and conservatory roofs collect algae readily in this climate, particularly on shaded elevations and anywhere under a tree.

It cleans up very well, because none of it has penetrated. Hot water, a soft brush and a mild detergent usually restore uPVC close to its original appearance, and pole-fed systems mean fascias and soffits can be reached from the ground with no ladders on most domestic and low-rise commercial properties.

The one honest caveat is age. Twenty-year-old uPVC that's chalky from UV exposure will clean up but won't come back white — the surface itself has degraded and the yellowing is in the material. Cleaning removes the green; it doesn't remove the years. We say that before the job rather than after.

Bus shelters, canopies and play equipment

Plastic panels in public spaces take a lot of abuse: tagged, stickered, scratched and etched. Paint and stickers come off well. Scratching and etching — as with glass — is physical damage to the panel and can't be cleaned out; the panel needs replacing, ideally with anti-graffiti film applied so the next attack is a film swap rather than a replacement.

Plastic play equipment is straightforward and satisfying to clean, and again mostly a safety job — green plastic slides and steps are slippery. We work chemical-free on play surfaces wherever possible, and we'll photograph any cracked or UV-brittle components we come across, since brittle plastic on equipment children use is worth knowing about early.