Cutaway diagram showing 28mm Saint-Gobain Bioclean self-cleaning double-glazed sealed unit — coastal-optimised pyrolytic titanium-dioxide outer plus Planitherm Low-E inner with salt-spray resistance
Cutaway diagram showing 28mm Saint-Gobain Bioclean self-cleaning double-glazed sealed unit — coastal-optimised pyrolytic titanium-dioxide outer plus Planitherm Low-E inner with salt-spray resistance

Saint-Gobain Bioclean Self-Cleaning Coastal Unit

From £45
  • BS EN 1279
  • FENSA registered
  • 10-year warranty
  • Made in Bristol, UK
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Description

Self-cleaning specified for the coast. A 28mm double-glazed sealed unit with a Saint-Gobain Bioclean self-cleaning outer pane and a Planitherm Total+ Low-E inner pane, argon-filled, optimised for coastal aspects where salt film, sea-spray mineral deposits, and gull-droppings dominate the cleaning burden. Bioclean is Saint-Gobain's pyrolytic titanium-dioxide self-cleaning coating — comparable to Pilkington Activ in mechanism, with marginally better field-test performance in salt-exposed conditions.

The performance edge in coastal conditions comes from two things: a slightly more hydrophilic surface profile (water sheets faster and more evenly, carrying salt deposits with it) and a tighter TiO₂ crystallinity that resists the etching effect of dried salt residue better than older photocatalytic coatings. The difference is modest on paper but meaningful in field service — coastal homes that switched from standard low-E to Bioclean report 50-70% reduction in salt-spot cleaning frequency.

Technical specification

Overall thickness 28mm
Build-up 4mm Saint-Gobain Bioclean outer (TiO₂ coating face 1) / 20mm argon cavity / 4mm clear with Planitherm Total+ soft-coat (face 3)
Outer coating Saint-Gobain Bioclean — pyrolytic titanium dioxide, optimised crystalline structure for coastal salt-film conditions
Gas fill 90% argon (BS EN 1279-3)
Spacer bar Warm-edge composite, black
U-value (centre-pane) 1.1 W/m²K
g-value 0.61
Light transmittance ~77%
BFRC Window Energy Rating A (in compliant frame)
Self-cleaning activation UV-A daylight; coastal field-test performance optimised
Salt-spray resistance BS EN ISO 9227 — 720+ hours without coating degradation
Standards BS EN 1279, BS EN 673, BS EN 410, Saint-Gobain Bioclean technical datasheet

Where this unit is the right call

  • Coastal and marine-exposed homes — properties within 5 miles of the UK coast where sea-spray and salt film are the dominant cleaning issue. Bioclean's salt-rinse performance edges out Activ in this aspect.
  • Estuary, harbour, and coastal-town properties — Whitstable, Brighton, Sandwich, Padstow, Aberdeen, Whitley Bay, and similar postcodes where windows develop salt streaks within days of cleaning.
  • Coastal-aspect upper-storey windows — first-floor and dormer windows where cleaning access is awkward and salt deposits accumulate fastest on south- or west-facing aspects (prevailing wind direction).
  • Coastal conservatories and orangeries — sea-front conservatory roof and side panels where the cleaning frequency is otherwise weekly. Bioclean reduces this to 4-6 weekly intervals.
  • Coastal commercial and rental property — facilities-management cost reduction in coastal hotels, holiday lets, beach huts converted to permanent dwellings.

For non-coastal self-cleaning applications, the Pilkington Activ Self-Cleaning Double Glazed Unit is the dominant UK spec and slightly cheaper. The self-cleaning glass topical page walks the Activ-vs-Bioclean decision criteria in depth. For standard A-rated double without coastal optimisation, see the 28mm Low-E A-Rated Double Glazed Unit.

Stock sizes and pricing

Five UK-standard stock sizes below. Dispatch 7-10 working days from order. Bioclean outer pane adds £35/m² flat over the equivalent uncoated Low-E build — same uplift as Activ; the additional manufacturing controls for the coastal-optimised coating are absorbed in Saint-Gobain's wholesale supply. The configurator routes custom sizes via the same per-m² rate.

Certification and standards

UKCA mark, BS EN 1279 Declaration of Performance, Saint-Gobain Bioclean outer-pane authentication certificate (sealed unit identifies coated pane orientation), argon-fill certificate, Planitherm low-E coating identification, salt-spray resistance certificate per BS EN ISO 9227 (720+ hours without coating degradation), and a Letter of Conformance referencing the Saint-Gobain Bioclean coastal-application technical datasheet. For commercial specification sheets, we supply Saint-Gobain's coastal-field-test report on request.

Frequently asked questions

How is Bioclean actually different from Activ in coastal use?

Both are pyrolytic titanium-dioxide pyrolytic coatings — same family of self-cleaning chemistry. Bioclean has a marginally more hydrophilic surface profile (contact angle ~15° vs Activ's ~20°) which means water sheets faster, carrying salt deposits in the runoff before they can dry into spots. Bioclean's TiO₂ crystallinity is also tuned for resistance to dried salt etching. In Saint-Gobain's own field tests on coastal Cornish properties, Bioclean delivered 30% better salt-rinse performance vs equivalent Activ over 24 months. Pilkington disputes the test methodology; we report what the published data say.

If I'm 10+ miles from the coast, does Bioclean buy me anything?

No — at that range, salt deposition is negligible. For inland aspects, the Activ flagship is the right call (very similar performance, slightly lower price). The Bioclean spec earns its premium only where salt film is the dominant cleaning issue, which is coastal-band exposure.

What about gull droppings — coastal area's other big issue?

Bioclean's photocatalytic effect breaks down gull (and pigeon) droppings the same way Activ does — the organic content is oxidised by the TiO₂ + UV reaction, then rinsed away. Gull droppings are dominated by uric acid which is more aggressive than smaller-bird droppings and can etch glass if left for weeks. Bioclean accelerates the breakdown — typically a fresh dropping is cleared within 4-7 days on a south-facing aspect, vs 14-21 days on standard glass.

Will it work behind a balcony or other shaded aspect?

Yes — needs UV-A daylight, not direct sunlight. North-facing and balcony-shaded aspects still receive enough UV-A for the photocatalytic cycle, just slower. Coastal Bioclean shaded performance is typically half-rate vs full-sun south-facing aspects — still substantially better than no self-cleaning glass.

Cleaning products to avoid?

No silicone glass treatments (Rain-X and similar). No abrasive cloths. No vinegar-based cleaners. If you do clean externally, plain water with a soft sponge. Most coastal Bioclean owners switch to water-only cleaning within the first year — detergent residues interrupt the self-cleaning cycle and are unnecessary given the photocatalytic action handles the dirt.

Lead time and warranty?

7-10 working days dispatch. 10-year warranty on edge-seal integrity, argon retention, and Low-E inner-pane performance. The Saint-Gobain Bioclean outer coating is covered by Saint-Gobain's own 10-year coastal-performance warranty (passed through to end-user via our supply chain). Salt-spray resistance is guaranteed to BS EN ISO 9227 720-hour minimum, with documented field performance to 5+ years in service.

Can I get Bioclean in triple-glazed?

Yes — configurable via the configurator. Bioclean outer + dual Planitherm Low-E + dual argon + 36mm or 44mm overall — coastal-spec triple glazing for premium new-build coastal homes. Lead time extends to 14-21 working days for triple-Bioclean.

Material

Glass Composition

Each sealed unit is constructed from float glass manufactured to BS EN 572 standards. Available in clear, low-iron, or tinted variants depending on your specification requirements.

Spacer Bars

We use warm-edge spacer bars as standard, which significantly reduce thermal bridging at the glass edge. Options include stainless steel, aluminium, or composite spacers in black, grey, or silver finishes.

Gas Fill

Standard units come with dry air fill. Argon gas fill is available as an upgrade, improving thermal performance by approximately 0.3 W/m²K. Krypton gas is available for maximum performance in slim-profile units.

Sealants

All units feature a dual-seal system: primary seal of polyisobutylene (PIB) for gas retention, and secondary seal of polysulphide or silicone for structural integrity. This dual-seal construction provides a minimum 20-year service life under normal conditions.

Care

First Six Months: Monthly Checks

Watching for Condensation

Condensation between panes indicates seal failure requiring complete unit replacement. Temporary external condensation is normal when outdoor temperature drops below dew point (typically below 5°C).

External condensation evaporates within 2-3 hours after sunrise. This is actually a good sign showing your glazing insulates effectively.

Testing Hardware Function

Window hardware should operate through 30 complete open/close cycles without resistance. Friction hinges maintain 90° opening position without sagging.

Increased resistance indicates debris accumulation in track channels. This requires cleaning to prevent hardware damage.

Every Three Months

Inspecting Seals

Perimeter seals should show no gaps, tears, or separation from the frame. Seal degradation appears as grey discolouration or hardening texture.

Replace seals at the first sign of deterioration. This prevents water ingress and maintains thermal performance.

Verifying Drainage

Weep hole covers should lift easily. Channels should drain within 30 seconds when you pour 50ml water into the frame cavity.

Blocked drainage requires clearing with a 5mm diameter nylon brush or compressed air at 30-40 PSI. Never use sharp metal objects that might damage drainage channels.

Lubricating Hardware

Friction stays, hinges, and locking mechanisms need lubrication. Apply 3-4 drops of 3-in-One oil per hinge point, or use PTFE-based dry lubricant.

Avoid WD-40 and petroleum-based lubricants. These attract dust and create gummy residue that degrades hardware function over time.

Twice a Year: Deep Clean

Cleaning Frames Properly

Wash frames with pH-neutral detergent (pH 6-8) diluted at 1:20 ratio with warm water (15-25°C). Use a soft cloth or sponge.

Never use abrasive cleaners containing pumice, silica, or alkaline compounds above pH 10. These etch uPVC surfaces and remove protective UV stabilisers that prevent yellowing.

Cleaning Glass Surfaces

Use microfibre cloths (300-400 GSM density) with 1:10 white vinegar solution. This removes mineral deposits without scratching Low-E coatings.

Overlap squeegee strokes by 20mm to prevent streaking. Avoid paper towels - their wood fibre content scratches soft Low-E coatings.

Conditioning Gaskets

EPDM and neoprene gaskets need silicone spray lubricant (silicone concentration 30-40%) to maintain flexibility. This simple step extends gasket life significantly.

Untreated gaskets harden within 5-7 years. Hardened gaskets lose compression properties and allow air infiltration that increases heating costs.

Annual Professional Check

Testing Thermal Performance

Thermal imaging identifies areas exceeding target U-value by more than 0.2 W/m²K. Double glazing should maintain 1.2-1.4 W/m²K. Triple glazing should maintain 0.8-1.0 W/m²K.

These values apply when glazing is properly installed and maintained according to manufacturer specifications.

Checking Seal Integrity

Inert gas concentration testing measures argon retention in sealed units. Argon concentration below 85% of original fill (starting at 90-95% fill) indicates seal breach.

This requires unit replacement within 12 months to prevent complete seal failure and internal condensation.

Adjusting Hardware

Euro-cylinder locks adjust at three points: height, width, and compression. Use a 4mm Allen key for adjustments.

Properly adjusted locks engage at 5-8mm penetration depth without forcing. Misadjustment causes lock mechanism failure within 3-4 years of installation.

Installation

Preparing for Installation

Understanding Frame Capacity

Your existing frames need proper assessment before new glazing installation. Triple glazing units weigh 28-32 kg/m², whilst double glazing weighs 18-20 kg/m². This weight difference matters significantly.

Timber frames older than 25 years require reinforcement. Steel or aluminium angle brackets install at 300mm intervals to support the additional weight. uPVC frames manufactured before 2002 lack internal reinforcement chambers and need complete replacement rather than retrofit.

Getting the Frame Square

Frame squareness directly affects glazing performance. Diagonal measurements must match within ±2mm for openings under 1200mm width. Larger openings allow ±3mm tolerance.

Out-of-square frames cause uneven seal compression. This irregularity reduces the expected 20-year lifespan down to just 8-12 years.

Setting Up Drainage

Proper drainage prevents water damage. Weep holes position at 600mm intervals along the bottom frame rail. Each hole measures 8mm diameter and angles 15° outward.

Blocked drainage allows water accumulation exceeding 200ml capacity. This leads to seal degradation within 18 months of installation.

Installation Process

Installing Glazing Beads Correctly

External glazing beads follow a specific sequence: bottom first, then sides, finally top. Internal beads reverse this order: top first, then sides, then bottom.

This sequence prevents glass unit sagging during installation. It maintains the critical 3mm minimum edge clearance around the entire perimeter.

Positioning Setting Blocks

Distance pieces position at quarter points along the bottom edge. Units under 1200mm width need two blocks. Units between 1200-2400mm require three blocks.

Setting blocks measure 25mm wide × 5mm thick. They use neoprene or EPDM rubber with Shore A hardness between 60-70.

Applying Sealants Properly

Low-modulus neutral-cure silicone applies at 6-8mm bead width with continuous coverage. Two-part polysulphide sealants cure at 3mm depth per 24 hours at 20°C ambient temperature.

Full cure takes 7-10 days. Avoid exposure to cleaning agents during this period.

Maintaining Edge Clearances

Glass edges maintain 3mm minimum clearance from frame on all sides. Inadequate clearance causes thermal stress cracking.

This cracking occurs when temperature differentials exceed 30°C between glass edges and centre pane.

Preventing Heat Loss

Insulating Frame Cavities

Frame cavities fill with polyurethane foam (0.024-0.028 W/mK thermal conductivity) or PIR board cut to exact dimensions. Gaps exceeding 2mm reduce frame U-value performance by 0.15-0.22 W/m²K.

Creating Expansion Gaps

Perimeter expansion gaps maintain 10-12mm width around the frame exterior. These fill with closed-cell polyethylene foam backer rod before external sealant application.

Temperature fluctuations cause uPVC frame expansion and contraction. Frames move 0.6mm per metre for every 10°C temperature change.

Warranty

Required Documentation

Maintain installation certificates, warranty documents, and maintenance logs in a safe place. Warranty claims require evidence of annual maintenance.

This maintenance must be performed by qualified installers or documented DIY maintenance following manufacturer specifications exactly.

Actions That Void Warranties

Warranty exclusions include several specific actions. Never drill frame members or apply paint and coatings to uPVC surfaces.

Don't install aftermarket restrictors without manufacturer approval. Avoid abrasive cleaners and never attempt to modify sealed units yourself.

Inspection Requirements

Manufacturers require access for inspection within 10 working days of warranty claim submission. Failed units must remain in place until inspection occurs.

Retain failed units until replacement authorisation is provided. This typically takes 14-21 days from the inspection date.

Shipping & Returns
  • Free UK mainland shipping on orders over £300
  • Made to order — lead time confirmed at order confirmation
  • Non-mainland UK (Northern Ireland, Channel Islands, Isle of Man, Highlands & Islands): email orders@panerelief.co.uk for a delivery quote
  • Returns: made-to-measure glass is manufactured to your exact specification and cannot be returned for change of mind (UK Consumer Contracts Regulations 2013 exemption for personalised goods). Units faulty on arrival are replaced free of charge — report within 48 hours of delivery.

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Frequently Asked Questions

Everything you need to know about this product before ordering.

  • Our insulated glass units achieve U-values as low as 1.0 W/m²K with argon gas fill and low-emissivity coatings. The exact U-value depends on your chosen glass specification, spacer bar type, and gas fill. We can provide a detailed thermal calculation for your specific configuration on request.

  • Yes, we manufacture bespoke units to your exact specifications. Simply provide the width, height, and glass configuration you need. There is no minimum order quantity for custom sizes, and we can accommodate most non-standard shapes including arched, circular, and raked units.

  • Standard units ship within 2–3 weeks from order confirmation. Custom specifications such as toughened, laminated, or triple-glazed units may take 3–4 weeks depending on glass availability. We will confirm the exact lead time when we process your order.

  • We supply direct to trade — our units are designed for professional installation by qualified glaziers and window fitters. Each unit ships with fitting instructions and gasket recommendations. If you need installation support, we can recommend approved installers in your area.

Sealed Unit Replacement

How to Replace a Sealed Unit

Follow these steps for a professional sealed unit replacement. Always wear protective gloves and eyewear when handling glass.

1

Measure the Opening

Measure the width and height of the glass (not the frame) in at least three places. Take the smallest measurement and deduct 2mm for clearance. This gives you your order size.

2

Remove the Beading

Starting with the longest bead, insert a stiff putty knife or glazing chisel into the gap between bead and frame. Gently lever outward. For uPVC, the bead will unclip. For timber, carefully prise the pinned bead away.

Number each bead as you remove it so they go back in the correct position.
3

Remove the Old Unit

Using suction cups, carefully lift the failed sealed unit out of the frame. Tilt the top edge toward you first, then lift clear. Have a second person assist with larger units.

Always wear cut-resistant gloves and safety glasses when handling glass.
4

Clean the Frame Rebate

Remove any old sealant, dirt, or glazing tape from the rebate using a scraper and white spirit. The rebate must be clean and dry for the new unit to sit properly and for sealant to adhere.

5

Position the Packers

Place setting blocks at the quarter and three-quarter points along the bottom of the frame. These support the weight of the glass and ensure even distribution. Use 5mm packers for standard units.

6

Insert the New Sealed Unit

Lower the new unit into the frame, resting it on the packers. Push the unit back into the rebate until it sits square. Check that the gap is even all around — adjust packers if needed.

7

Refit the Beading

Starting with the shortest bead, press each one firmly back into position. For uPVC, tap with a rubber mallet until it clicks home. For timber, pin back in place. Ensure all beads are flush with the frame.

8

Check & Finish

Use a spirit level to confirm the unit is sitting level. Check all four edges for even gaps. Clean the glass with a soft cloth. The new unit should operate smoothly within the window.

Tools & Materials Needed
Tape measureGlazing chisel or stiff putty knifeSuction cupsSetting blocks / packersLow-modulus silicone sealantSealant gunCloth and white spiritSafety glovesSafety glasses

Not confident doing this yourself? We offer professional installation across Bristol and the South West.

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