Koi Pond Renovation with Patio and Viewing Window – Eltham, London

A new pond for an experienced koi keeper

We rebuilt Denis’s koi pond in Eltham, London, after more than 25 years of use. He wanted a deeper pond, a clearer view of the fish and an updated garden setting, while keeping the hands on part of koi keeping that he enjoyed.

That preference shaped the filtration choice. The new pond uses a Nexus 320 and a separate bead filter on the skimmer line, rather than a fully automated drum filter system. The large front window and surrounding patio make the koi easier to watch from the garden.

Alongside the pond renovation, the surrounding patio areas were updated to better frame the pond and improve how it is enjoyed within the garden.

Renovating a 25 Plus Year Old Koi Pond in London

The original pond was mostly sunken into the ground with a small raised section, planting shelves, and a modest waterfall feeding into the main pond. It also included a raised planting pond that housed aquatic plants. While it successfully supported over 20 large koi carp, the layout limited depth consistency and made maintenance more challenging over time.

As part of the renovation, the entire pond structure was removed and rebuilt. The new design focused on creating one main deep koi pond with a consistent depth, removing shelves and increasing usable water volume. A separate raised pond was retained for planting, allowing plants to be enjoyed without compromising the koi pond environment.

This approach allowed the pond to be modernised while respecting how the customer enjoyed using it.

Concrete Block Construction and Fibreglass Lining

The new koi pond was constructed using concrete blockwork, providing a solid and long lasting structure. Once built, the pond was professionally fibreglass lined, creating a smooth, seamless, and highly durable finish that is ideal for koi ponds.

Fibreglass lining offers excellent longevity, ease of cleaning, and a clean appearance, making it a popular choice for koi pond renovations in London where long term reliability is essential.

A large front viewing window was built into the pond wall, measuring 2 metres wide and nearly 1 metre high. This allows the koi to be enjoyed at eye level and has become one of the standout features of the pond.

Filtration Built for Hands On Koi Keeping

Rather than installing a drum filter, the filtration system was designed around the customer’s preference for hands on pond care.

The main pond is filtered using a pump fed Evolution Aqua Nexus 320 connected to a retro bottom drain. This provides strong biological filtration while allowing the customer to remain actively involved in maintaining the system. Our Evolution Aqua Nexus guide explains how the filter works and what its routine care involves.

On the skimmer line, an Evolution Aqua Advanced bead filter was installed, with multiple returns feeding clean, filtered water back into the pond. The main pond and skimmer therefore have separate filtration routes, with the equipment housed together for access and routine care.

A bespoke wooden filter shed was built to house the filtration equipment, keeping everything protected, accessible, and neatly tucked away.

Stainless Steel Blade Waterfall and Raised Plant Pond

Water from the raised planting pond flows back into the main koi pond via a custom built stainless steel blade. This creates a clean, modern waterfall effect that contrasts nicely with the pond’s contemporary finish.

The stainless steel blade provides a smooth, even sheet of water, adding movement, sound, and oxygenation to the pond while maintaining a sleek appearance. It also clearly separates the planting area from the koi pond, allowing both elements to be enjoyed without compromise.

Patio Works Around the Pond

While this was primarily a koi pond renovation, patio works were carried out around the pond to improve access, viewing, and overall presentation.

New paving was installed around the pond edges, creating practical seating and standing areas that allow the pond and viewing window to be enjoyed from multiple angles. The updated patio layout helps frame the pond and makes it a central feature within the garden without overwhelming the space.

The Finished Result

The completed koi pond renovation has transformed an ageing but much loved pond into a modern, striking feature that sits comfortably within the garden.

The customer was extremely happy with the result and now enjoys a deeper, cleaner, and more visually impressive koi pond that still allows him to stay involved with its care. The viewing window, fibreglass finish, stainless steel blade waterfall, and improved patio areas have combined to create a pond that is both practical and visually impactful.

Considering a Koi Pond Renovation in London?

An existing pond can be rebuilt around the fish you keep and the way you want to care for them. Our koi pond building service covers both new ponds and renovations. From structural rebuilds and fibreglass lining to filtration upgrades, viewing windows, and water features, we design koi pond renovations that suit both your fish and how you enjoy your pond.

If you are based in London or the surrounding areas and are considering a koi pond renovation, get in touch to discuss your ideas and arrange a site visit.

View Our Pond Services

This project is just one example of the range of pond and garden work we carry out, from bespoke koi pond builds and full garden transformations through to specialist renovations and long term pond care.

To explore everything we offer, including pond cleaning, pond maintenance, fibreglass lining, filtration upgrades, and custom pond construction, please visit our main pond services page to see how we can help with your own project.

👉 View all our pond care services

You can also explore the koi pond showcase, or browse other work in our pond projects section to see the standard of work we deliver across Kent, Sussex, and the South East.