
25.5mm Pond Viewing Window – Toughened Laminated Glass UK
A 25.5mm pond viewing window offers a strong and versatile solution for a wide range of pond builds, combining excellent load-bearing performance with clear optical quality. It’s widely specified for medium-depth ponds, koi ponds, and larger viewing panels where increased rigidity is needed.
Made-to-measure 25.5mm pond glass with polished edges. Delivery usually takes 8–10 working days; up to 15 working days during busier periods.
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What Is a 25.5mm Pond Viewing Window?
25.5mm pond glass is manufactured by laminating two panels of toughened safety glass using a high-strength interlayer. This results in a rigid panel that can withstand higher water pressure and greater structural loads than thinner glass options.
The laminated construction also provides an additional safety layer, helping to reduce the risk of sudden failure in the unlikely event of impact.
Buy pond glass today!
For made-to-measure 25.5mm pond glass, use our pond window price calculator for VAT-inclusive prices and postcode delivery. Browse standard sizes below or contact us for unusual specifications.
Pond Viewing Window Thickness Comparison
Typical maximum recommendations. All figures assume correct installation into a suitable structural rebate with full edge support.
21.5mm
Max panel depth: Up to 400mm (16 inches)
Max panel width: Up to 1600mm (63 inches)
Best suited for: Shallow garden ponds, sleeper ponds, decorative or wildlife ponds
25.5mm
Max panel depth: Up to 600mm (24 inches)
Max panel width: Up to 2000mm (79 inches)
Best suited for: Medium-depth ponds, koi ponds, raised sleeper ponds
33mm
Max panel depth: Up to 1000mm (39 inches)
Max panel width: Up to 2000mm (79 inches)
Best suited for: Deep koi ponds, large raised ponds and projects requiring increased strength
39mm
Max panel depth: Up to 1000mm (39 inches)
Max panel width: Up to 3000mm (118 inches)
Best suited for: Very wide viewing panels, deep ponds and high-end or showcase installations
44.5mm
Max panel depth: Up to 1200mm (47 inches)
Max panel width: Up to 3500mm (138 inches)
Best suited for: Large, deep water features and specialist or commercial pond installations
Important notes:
Sizes shown are indicative and depend on panel proportions and installation method.
All pond viewing windows should be toughened, laminated and heat soaked.
Final thickness selection should always be confirmed before manufacture.

When Should You Use 25.5mm Pond Glass?
A 25.5mm pond viewing window is ideal when your pond design falls between smaller, decorative builds and deep, structural applications. It performs exceptionally well where:
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Water depth is moderate
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Viewing panels are wider
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Long-term performance and strength are required
This thickness is often chosen over a 21.5mm viewing window when additional rigidity is preferred without moving into heavy-duty specifications such as 33mm or 39mm.
Recommended Panel Sizes
The performance of 25.5mm pond glass depends on panel width and depth, as well as correct support and installation methods.
Typical recommendations for 25.5mm pond viewing windows are:
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Maximum Panel depth: up to 600mm (24 inches)
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Maximum panel width: up to 2000mm (79 inches)
These general guidelines assume installation into a structurally sound rebate with adequate support on all sides.


25.5mm Compared With Other Pond Glass Thicknesses
Compared with 21.5mm pond glass, 25.5mm provides stronger resistance to water pressure and greater rigidity, making it suitable for larger or deeper applications.
Compared with 33mm pond viewing window glass, 25.5mm is lighter, more cost-effective, and typically chosen for most domestic koi pond builds and medium-depth installations.
Choosing the correct thickness ensures safety, durability, and long-term performance for your pond viewing window.
Glass Specification & Safety Features
All 25.5mm pond viewing windows supplied by Fusion Glass Ltd are:
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Toughened
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Laminated
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Heat soaked
Polished edges are included as standard for safety and aesthetics, with dubbed corners supplied as standard to minimise stress points.
This specification ensures that the glass performs reliably when installed correctly within your pond structure.

Pond Glass Delivery & Lead Times
Fusion Glass Ltd supplies 25.5mm pond viewing windows across the UK, providing reliable nationwide delivery for domestic and trade customers.
Pond window delivery is usually 8–10 working days from order confirmation. During busier periods, please allow up to 15 working days.
Once your glass is ready, we will contact you to confirm delivery scheduling.
Delivery Times, Access & Offloading
Deliveries are made Monday to Friday between 07:30 and 17:30. Please ensure someone is available on the delivery day, and ideally the following day, to receive the glass.
All pond glass is delivered kerbside only. Suitable access must be available for the delivery vehicle.
Due to the weight of glass panels, at least two people are required for every 85kg of glass to safely offload. Glass is delivered unwrapped, and customers are responsible for safe handling once offloaded.
Delivery Areas & Additional Charges
We offer nationwide delivery across the UK. Additional delivery charges may apply for the following postcode areas:
AB, BT, CT, DD, DG, EH, FK, G, IV, KA, KW, KY, ML, PA, PH, PL, TD, TN23–TN30, TR
If your delivery address falls within one of these postcode areas, please contact us before ordering so delivery costs can be confirmed.
Inspection on Delivery
All pond glass must be checked immediately upon delivery before signing. Any damaged or defective glass must be reported and rejected at the time of delivery.
Order Accuracy & Amendments
Please ensure all sizes, thicknesses, and specifications are correct before confirming your order.
Cancellations or changes can be made within 48 hours of placing your order. After this period, the glass will be cut to size and no changes or refunds can be accepted.
Frequently Asked Questions – 25.5mm Pond Glass

Why Choose Fusion Glass Ltd?
Fusion Glass Ltd is a UK specialist supplier of pond viewing windows, supplying glass cut to size for bespoke pond projects.
We provide clear technical guidance to help ensure the correct thickness is selected for your design.
Nationwide delivery is available on all pond glass products.
Get a Quote for a 25.5mm Pond Viewing Window
If you’re planning a pond and believe 25.5mm pond glass is suitable for your project, get in touch with us today.
Please provide the required glass size, pond depth, and construction type so we can confirm suitability.
We’ll provide a clear, no-obligation quotation.


