Pond Glass Viewing Windows

Made to Measure Pond Glass Viewing Windows

Toughened, Laminated and Heat Soaked Glass for Koi Ponds, Water Features and Natural Swimming Ponds

Important ordering information: Every panel is made to order in the UK. Select the glass thickness, enter the finished glass width and height in millimetres, and the calculator will work out the price. A £200 minimum charge per panel applies. Typical delivery is 2 to 3 weeks.

A pond viewing window completely changes the way you experience a pond. Instead of only seeing fish from above, you can watch them move and feed below the waterline while the glass gives a raised koi pond, swimming pond or contemporary water feature a clean architectural finish.

Our pond glass is manufactured for demanding aquatic installations using laminated, toughened and heat soaked safety glass. Panels are available in 21.5mm, 25.5mm, 33mm, 39mm and 44.5mm thicknesses, so you can order a compact garden pond window or a much wider open top infinity style panel to suit the build.

How to Order Your Pond Window

1. Select the glass thickness. Use the guide below or ask us to check the specification.
2. Enter the finished width and height. Measurements must be entered in millimetres and should be the required glass size, not the structural opening.
3. Review your total glass price. Your quotation shows the finished panel price including VAT. The existing £200 minimum applies to each panel, separately from optional sealant.
4. Add installation sealant if required. Choose a compatible black sealant, review the estimated cartridge quantity and add spare tubes if needed. Sealant appears as a separate item in your basket.
5. Check access and offloading arrangements. Pond glass is heavy, made to order and delivered kerbside.

For more design, installation and delivery guidance, visit our pond viewing windows guide and FAQs.

Choosing the Correct Pond Glass Thickness

Glass thickness is influenced by the water depth at the window, the panel width and the way the surrounding structure supports the glass. The following sizes are a practical general guide for the options available on this page.

Unsure which thickness to order? Please contact us before purchasing. For unusually wide panels, deeper water or unusual structures, the specification should be checked for the individual installation.

Built for Strength, Clarity and Long Term Reliability

• Made to measure for the finished dimensions you provide
• Laminated and toughened safety glass construction
• Heat soaked to reduce the risk of spontaneous breakage
• Polished edges and neatly finished safety corners
• Suitable for raised koi ponds, natural swimming ponds and architectural water features
• Available for rebate installations and open top infinity style pond windows

Lamination helps the layers remain bonded in the unlikely event of damage, while the polished finish creates a clear and professional viewing area when correctly installed.

Measuring Your Glass and Preparing the Rebate

Enter the finished glass width and height in millimetres, not the visible opening or the outer rebate pocket. The glass overlaps the supporting rebate, so these are different measurements. Measure the finished, fibreglassed surfaces and check the opening in several places before ordering.

For our usual open top installation, we form a 50 × 50mm rebate on the inside of the pond wall and finish it with fibreglass. We normally size the glass to leave approximately 10mm clearance at its left, right and bottom edges. Suitable packers maintain the bottom clearance during installation. This makes room for installation tolerances and irregularities in the fibreglass finish.

We normally allow around 8mm of sealant between the glass face and the fibreglassed rebate once the panel is pressed into position. We also fill the 10mm edge gaps and finish with a smooth bead. The edge clearance and the face sealant bed are separate dimensions.

Check the actual rebate depth against your glass thickness. For example, 44.5mm glass plus an 8mm bed totals 52.5mm. It cannot sit fully recessed within a finished 50mm deep rebate using that arrangement. A different depth or installation detail must be agreed.

These details describe our typical installation method, not a structural design for every pond. Water depth, glass dimensions, support, substrate compatibility and the sealant manufacturer’s instructions still need checking. Larger or unusual windows should be assessed before purchase.

Estimating Your Sealant Quantity

Choose three sealed edges for an open top window, or four for a window sealed around its full perimeter. The estimate uses your finished glass width, height and thickness, then rounds up to complete cartridges of the selected product.

For the usual rebate described above, the model assumes a nominal 40mm glass overlap on the 50mm rebate after allowing the 10mm edge gap. It includes the 8mm face bed and filled edge cavities. Four sided estimates assume the same clearance and joint arrangement at the top.

A clearly stated 15% estimating allowance is included for a modest finishing bead and wastage. This is not a manufacturer specification or a guarantee of usage. Rough or irregular surfaces, wider gaps or a larger finishing fillet may need extra material. You can add spare tubes.

Our separate practical guide of one tube per 200mm of sealed edge is a more generous allowance and already includes wastage. We do not add another 15% to that rule. The calculator uses the stated joint-volume model above; check it against your actual installation and add spares if needed.

As an example, a 1600 × 600mm panel in 25.5mm glass, sealed on three sides, gives an estimate of eight 290ml cartridges or seven 310ml cartridges under these assumptions. This is a material estimate, not approval of that glass specification or installation.

Not all pond sealants are conventional silicone. Check the instructions for your exact adhesive, including compatible substrates, preparation, support and curing before filling the pond.

Recommended Pond Sealants

Choose the right product for your materials and installation. Our preferred order of options is:

1. Pond Bond Adhesive & Sealant — our own 310ml modified polymer adhesive and sealant, available in black or clear. The window calculator uses black. Follow the application guidance for your materials, joint arrangement and curing conditions.
2. Gold Label Underwater Pond Sealer. An alternative for suitable pond sealing and bonding work, including wet conditions. Follow the product instructions for preparation, joint arrangement and curing.
3. AquaForte Superstrong Fix & Seal. A modified polymer adhesive and sealant for compatible pond materials. The window calculator offers the black version. Follow the instructions for the application.

The calculator will use the cartridge size, current selling price and availability of your selected product. Sealant is added separately from the glass, making it easy to see exactly what you are buying. Browse our pond glues and sealants for more information.

Delivery and Offloading Requirements

Some postcode areas have a glass delivery surcharge. Check the areas below before ordering. Do not assume the general website free delivery message applies to every made to measure glass delivery. Where a surcharge requires a quotation, contact us before paying.

Please do not book installation work until the glass has been safely delivered and inspected.

• Typical delivery is 2 to 3 weeks, although busy periods can take longer.
• Delivery is kerbside only and the glass is supplied without packaging to avoid pressure points and trapped moisture.
• Deliveries normally take place between 07:30 and 17:30 and require a signature.
• The driver will normally contact you approximately one hour before arrival.
• Allow at least two capable people for every 85kg of glass. The driver may not be able to help with offloading.
• Ensure the delivery vehicle can gain safe access. Failed delivery caused by restricted access or insufficient help may incur a redelivery charge.

Areas Subject to an Additional Delivery Charge

Additional delivery charges apply to the following postcode areas: AB, BT, CT, DD, DG, EH, FK, G, IV, KA, KW, KY, ML, PA, PH, PL, TD, TN23–TN30 and TR.

Important Checks Before Placing Your Order

• All panels are made to order. Check your measurements and specification before manufacture and read our returns information.
• Check every measurement carefully before ordering.
• Confirm that the selected thickness is suitable for the water depth, width and structure.
• Plan safe access, lifting assistance and a secure location for inspection on delivery.
• A £200 minimum charge applies to each glass panel. This is passed on from the glass processor and delivery network rather than added as a separate That Pond Guy fee.

Need Help Choosing the Right Glass?

Building a lined pond? Our custom box welded EPDM pond liners can provide a neat, fitted lining for a rectangular pond. A viewing window still needs a suitable frame or rebate, support and a compatible liner-to-window sealing detail. Send us the plan before the liner is manufactured so these parts can be considered together.

We would much rather check a dimension or specification before the panel is manufactured than have you discover a problem on installation day. If you are unsure about the glass thickness, finished size, rebate or delivery arrangements, contact us and we will help you work through it.