Cladding cleaning: the right method for each material

First, work out what you have

uPVC cladding is hollow plastic, light, and sounds hollow when tapped; it is often white or cream and frequently runs into matching fascias and soffits. Composite boards are heavier, usually have a wood-grain pattern moulded in, and feel solid. Timber is real wood: you can see grain, knots and end-grain at the cut edges, and it weathers to silver if left untreated. If you are not sure, a close-up photo of a board end is usually enough for us to tell.

This guide sits under our Wall Cleaning & Softwash work, covering 20-mile radius of Plymouth.

uPVC: low pressure and a cleaner

Plastic cladding is cleaned at low pressure with a suitable cleaner rather than force. The danger is not the plastic itself but water driven behind the boards and into soffits. Green algae on shaded runs is treated at the same time. One thing a clean will not fix is yellowing on sun-facing plastic, because that is the material degrading rather than dirt sitting on it; the shaded side will come up brighter than the south side however it is cleaned.

Composite: soft clean, check the maker

Composite cladding has a surface layer that can be scuffed by aggressive cleaning. We wash it at low pressure, treat any growth, and rinse. Some manufacturers publish their own cleaning guidance, and if you have it we will follow it. Treat scratches and fading as wear on the board, not grime, because they will still be there after a wash.

Timber: the gentlest of the three

Softwood and hardwood cladding is where force does the most harm. A jet raises the grain, leaving a furry surface that holds dirt and growth faster than before. Timber is cleaned with low-pressure softwash treatment and a gentle rinse, and it needs time to dry before any oil, stain or paint goes back on. Grey weathering on untreated timber is the wood itself changing colour; cleaning removes growth and dirt, not that silvering.

Why it is worth doing with the roofline

Cladding, fascias, soffits and gutter faces all get dirty for the same reasons: run-off, shade and airborne grime. Clearing the gutter first and then cleaning the boards below means the next downpour does not bring dirty water over the lip onto freshly cleaned cladding. Gutters are cleared from the ground with a vacuum pole and checked with a camera, so the whole roofline can be done in one visit.

What not to do yourself

Avoid a domestic pressure washer at close range on any cladding, avoid bleach-based products on timber, and do not scrub composite with abrasive pads. A soft brush, a bucket of mild cleaner and a hose rinse are fine for spot cleaning low boards between professional cleans. Higher boards, especially above a conservatory or on a gable, are better done from the ground with reach equipment.

Signs your cladding needs attention

Green or black streaks spreading from board joints, grime collecting on the top edge of each board, a slimy film on the shaded side, and dark tidemarks under gutter outlets are all signs cladding is due a clean. Pale chalky patches on painted boards and cracked or split timber are signs of wear instead, and are worth mentioning when you ask for a price so we can tell you what cleaning will and will not change. Catching growth early keeps the job gentle.