Why UPVC Goes from White to Grey in Liverpool
White UPVC fascias, soffits, bargeboards and window frames are virtually ubiquitous on Liverpool homes — and virtually all of them are less white than they used to be. The discolouration process is driven by several factors that are particularly pronounced in Liverpool. Green algae forms when moisture meets a suitable substrate — UPVC textured surface holds moisture and provides a foothold for biological growth, especially on north-facing elevations and under shaded eaves. Black mould forms in persistently damp conditions — not unusual in Liverpool's climate. Atmospheric pollution, particularly in areas near busy roads or the city centre, deposits grey-brown grime that embeds in the UPVC surface over time. UV exposure gradually degrades the white surface colourant, causing yellowing in south-facing UPVC over many years.
Professional UPVC Cleaning vs DIY
Many Liverpool homeowners attempt to clean their UPVC fascias and frames with household bleach or kitchen cleaners. While bleach can kill surface algae, it often discolours the UPVC itself, leaving brown or yellow staining worse than the original problem. Abrasive cleaners scratch the surface, making it more porous and therefore more susceptible to future algae growth. Professional UPVC cleaning uses specialist non-abrasive UPVC-safe solutions specifically formulated to dissolve biological growth and atmospheric staining without damaging the plastic surface or stripping its UV protection. The results are dramatically better than DIY cleaning — and they last longer because the correct treatments do not leave behind residues that attract further growth.
Never use bleach, abrasive pads or cream cleaners on UPVC fascias or window frames. These damage the surface and cause long-term discolouration that professional cleaning cannot fully reverse.
The Professional UPVC Cleaning Process
Under Pressure's UPVC cleaning process for Liverpool homes involves several stages. First, we apply a specialist UPVC-safe pre-treatment that begins dissolving biological growth and embedded atmospheric staining. This is left to dwell for 5-10 minutes while we prepare our equipment. Next, we use soft brushes with UPVC-safe cleaning solutions to agitate the surface, breaking down resistant deposits without scratching. We then rinse thoroughly with clean water to remove all cleaning solutions and loosened debris. For heavily stained sections, we may apply a second treatment and dwell period before final rinsing. The result is UPVC restored to its original brilliant white — or as close as possible, depending on the extent of UV discolouration from age.
Can All Yellowed UPVC Be Restored?
The honest answer is: most UPVC can be restored, but not all of it. Green algae, black mould and atmospheric grime can always be removed completely. These are surface deposits that professional cleaning removes entirely, leaving behind the original white UPVC surface. UV yellowing is different — it is a chemical change within the UPVC plastic itself caused by prolonged sun exposure, and no cleaning process can fully reverse it. The older the UPVC, the more UV yellowing is likely to be present. During our free assessment, we will look at your UPVC and give you an honest opinion on the likely results before any work begins. We will never guarantee results we cannot achieve.
How Often Should UPVC Be Cleaned in Liverpool?
For most Liverpool properties, UPVC cleaning every 12-18 months maintains brilliant white results. Properties in coastal areas like Crosby, Waterloo and Formby benefit from more frequent cleaning — every 12 months — due to faster salt and algae accumulation from the sea air. Properties with heavy tree coverage in areas like Aigburth, Childwall and Mossley Hill may also benefit from annual cleaning due to the sap and pollen deposits from overhanging branches. Combining UPVC cleaning with your annual gutter clean is an efficient approach — our teams can often complete both services in a single visit, saving you time and money. Under Pressure Exterior Cleaning covers all of Liverpool and Merseyside for UPVC cleaning with competitive prices and free no-obligation quotes.