Refurbishment of National Trust nursery glasshouse

Location: Nursery Glasshouse, near Bodnant Gardens, Colwyn Bay

Client: National Trust

Project overview:

Appointed by the National Trust to carry out extensive refurbishment works on their nursery site’s glasshouse, this project required a variety of essential upgrades to improve the structure, heating and irrigation systems.

Located near the renowned Bodnant Gardens in Colwyn Bay, the glasshouse comprises a twin-bay structure, each measuring approximately 6.5m wide and spanning 15m and 30m in length.

With a polytunnel and a portal frame workshop adjacent to the glasshouse, the improvements are designed to ensure the site meets the National Trust’s long-term sustainability goals.

Scope of our work:

With the existing XK structure designed with several obsolete components, the 3mm horti glass had become difficult to maintain and required complete replacement, alongside upgrades to the heating and irrigation systems.

To address these issues, we used like-for-like replacements where possible and worked closely with National Trust staff to safely remove and replace ageing infrastructure without causing irreparable damage.

Structure Refurbishment: Outdated glazing bars and 3mm horti glass replaced with new glazing components.

Glasshouse Heating: Installed two energy-efficient heat pump units to heat the smaller zone of the glasshouse, ensuring optimal temperature control.

Roof Ventilation: Fully overhauled the roof ventilation system, including the installation of new motor gearbox assemblies and control panels.

Irrigation: Designed and installed new hand-watering irrigation system connected to a mains cold water supply.

Doors: Installed four new top-hung aluminium sliding doors for improved access and insulation.

The Result

To give the glasshouse frame a fresh new look, we first replaced all missing nuts and bolts identified during the Structural Survey. This was an important step before tackling the roof refurbishment. The roof had been previously cleaned, but misting had developed in some areas. By replacing the glass with a like-for-like option, we’ve helped bring it back to life and preserve the structure for years to come.

To ensure the glasshouse stays at the right temperature, and achieve an uplift of 11°C, we installed two split-type heat pump units, which are energy-efficient and use reverse cycle refrigeration technology. This system uses approximately 6kW of energy, depending on the weather, to maintain optimal conditions without wasting energy.

The completed project ensures the National Trust now has a fully operational and sustainable glasshouse that meets both its agricultural and environmental needs. Thanks to our careful work on the refurbishment, the glasshouse now combines heritage conservation with modern functionality, providing a lasting solution for the future.

Reflecting on a successful project, Ian Dolman, Operations and Developments Manager at CambridgeHOK, said: “We’re proud to have played a key role in refurbishing such an important site for the National Trust. By combining modern energy-efficient systems with careful restoration, we’ve not only preserved the glasshouse but also ensured it remains sustainable and functional for their future long-term needs.”