UPVC and Fascia Boards: Why They Go Grey and How to Fix It
Those grey and green streaks on your fascia aren't just dirt — they're algae and atmospheric pollution. Here's why bleach makes it worse and what actually works.
5.0 Google Rating
Rated 5.0 across all Google reviews
Google Guaranteed
Verified, insured, backed by Google
Smart Seal Approved
Certified installer
No Deposit — Ever
100% satisfaction guaranteed
10+ Years Experience
200+ Essex properties cleaned
Fully Insured
Public liability cover
What Causes Grey and Green Streaks on Fascias
The discolouration on your UPVC fascia boards isn't simple dirt. It's a combination of algae, atmospheric pollution, and environmental grime. In Essex, we're dealing with diesel particulates from traffic, lichen spores carried on coastal winds, and airborne pollution that settles on any exposed surface. Over time, this builds into visible streaks and patches that make your home look older than it is. The problem is worse on north-facing fascias because they stay damp longer and get less direct sunlight. Once algae gets a foothold, it spreads quickly.
Why Bleach Makes It Worse Over Time
The instinct is understandable — bleach kills algae fast. But it's the wrong choice for UPVC. Bleach oxidises the UPVC surface, causing it to yellow and become brittle. You kill the algae today, but tomorrow your fascia is weaker and more discoloured than before. Within a year, the boards start to warp, crack, or split. Homeowners in Harlow and Braintree have learned this the hard way — they've scrubbed with bleach, seen their fascias fade and soften, and ended up paying for replacement years earlier than needed.
What a Proper UPVC Specialist Does Differently
A proper UPVC cleaner doesn't use bleach or high pressure. We use low pressure with specialist UPVC-safe cleaning solutions that are pH-neutral and biocide-based — they kill algae and lichen at the cellular level without damaging the plastic. The process takes longer than bleach, but the result is clean fascia that stays intact and maintains its colour for years, not months.
How Often Do Fascias Need Cleaning in Essex?
In Essex, we recommend professional UPVC cleaning every 18 to 24 months. The coastal damp and constant atmospheric pollution mean your fascias are under attack more than in inland areas. Southend-on-Sea and Colchester see more frequent regrowth because of salt spray and moisture. Heavily shaded fascias under trees may need cleaning every 12 months. In open, sunny areas, you might stretch to 24 months or beyond.
What Happens If You Ignore It
Algae and lichen are living things. They eat into the UPVC slowly, weakening it from the surface inward. UV damage compounds the problem — the sun breaks down the plastic further, making it more vulnerable to splitting and warping. After five or six years of neglect, your fascia boards are compromised enough that they start to crack or lift. Water gets behind them and damages the wooden backing boards and soffit underneath. In Billericay and Wickford, we've seen properties where owners ignored their fascias until they had to replace them entirely. Prevention is always cheaper.
Can You DIY Clean Your Fascias?
You can try, but it's risky. Pressure too high damages the plastic. Cleaning solutions designed for other surfaces can oxidise UPVC. Climbing a ladder to reach high fascias is hazardous. Most homeowners end up spending money and time and still don't get the results they expected. A specialist has the right equipment, the right products, and the insurance to do it safely.
FAQ: Will Cleaning Damage the Seal Between My Fascia and Gutter?
Not with our method. Low-pressure cleaning doesn't disturb the gutter seals or joints. In fact, cleaning regularly prevents algae from working into those joints and degrading the sealant, which is what causes leaks. We check the condition of the seals while we're there and flag anything that needs attention.
Ready for a free quote?
No deposit. No obligation. Call us directly on 07849 177724 or message us on WhatsApp.
Written by Terry
Owner, London & City Pressure Washing · Essex
Terry has cleaned driveways, roofs, patios and gutters across Essex for years. Every job done personally — no subcontractors, no shortcuts. Google Guaranteed and fully insured.
What Essex customers say
“London & City Pressure Washing come to do a roof and gutter clean on our property. They did an amazing job and were extremely friendly and professional. Highly recommended! Thanks again.”
Want results like these for your property?
No deposit. No obligation. Free quote — usually within 24 hours.
Learn more about our UPVC & Fascia Cleaning service →