A water tower with a heart of wood

Water Tower from Tonkin Liu_Interior-Tank_Dennis-Pedersen

In this reuse project by Tonkin Liu, a dilapidated water tower is transformed into an enchanting home by stabilizing the delicate steel frame with a strong timber core.

Water Tower from Tonkin Liu - Dennis Pedersen

Image © Dennis Pedersen: the renovated tower stands proudly overlooking the fields.

The steel-framed water tower, which had originally been used on an airfield at Great Massingham, was dissembled and moved just outside the village of Castle Acre in 1952, where it was bolted back together like a giant Meccano set.

With a ruined Norman castle, an 11th century abbey and a Bailey gate, the Norfolk village was already home to three notable ruins – and over time the rusting tower became its fourth.

After standing as a locally-beloved landmark for seventy years, the tower was saved from the scrapyard when it was bought at auction by photographer Dennis Pedersen. Now reinvented as a delightfully peculiar home, the water tower continues its life at the edge of the village.

A structure never designed to be lived in

Whilst driving across the countryside in France with his wife, Pedersen had often fantasised about what it would be like to live in a converted water tower. “I imagined placing a glass bowl over the top, and how incredible the views out over the flat landscape would be.”

Striving to maintain the original character and structure as much as possible, he enlisted architects Tonkin Liu and engineers Rodrigues Associates to help him transform the tower into a part-time home for his family. The main challenge in converting the tower into a liveable structure was stability. Although it had been designed to hold a great top-weight of water, the steel frame was delicate and flexible, and swayed in the wind.

Water Tower from Tonkin Liu_Interior-Staircase_Dennis-Pedersen

Image © Dennis Pedersen: the compression stair

CLT: a one-stop shop

Conventionally, steel is used to brace timber buildings. The strategy here however was the exact opposite. A CLT box of stacked bedrooms was built inside the frame, connecting to all four sides of the bracing, thus stabilizing it. Then, to deliver wind loads to the ground, a compression spiral stair tower was built next to the existing tower. As project architect Mike Tonkin succinctly put it: “we needed a stair and it was entirely logical to make the stair into a structure.”

Structural engineer Mervyn Rodrigues’ expertise in CLT was an important asset to the project. “We knew CLT was the best option,” Tonkin explains, “it gave us the timber interior, which Dennis was after, but also the structural strength.”

Informed by the structural logic of a seashell, the centralised strength at the core of the spiral stair meant that the stair tower’s walls didn’t need to be thicker than 80mm. Made from two flat packs of prefabricated pieces supplied by TDUK member Binderholz, the CLT bedrooms and staircase were fast to put up, cost effective and materially efficient.water tower by tonkin liu drawing

At one with the landscape

The unique character of the renovation entwines Tonkin Liu’s interest in storytelling and placemaking with Pederson’s appreciation of light. Within each key space – the tower, stair, bridge, tank and roof – there is a different relationship to nature and a different type of looking.

Facing north, away from the village, the cube-like bedrooms look out over a glorious wind-blown barley field, described by Tonkin as “an artwork in itself.” Small windows to the east and west provide cross ventilation and parallel the local castle, giving the building an impregnable, watchful feel.

The bridge that connects the sleep chambers to the CLT stair tower is glazed on both sides, looking out to the treetops. In contrast, the enclosed spiral stair tower is intentionally dim – other than a skylight which fills the vertical timber shaft with a soft top light. This creates an adventurous sense of ascent, leading to a dramatic unveiling when the top tank is reached.

In the tank at the top of the tower, the main communal living space is defined by its relationship to the horizon. Making reference to the line of the water level, a 360-degree ribbon window has been cut into the tank by removing one ring of panels. Like a parting of the waves, this slice creates a gravity-defying effect and allows a surrounding view of the landscape.

Having hosted a number of open days at the tower, attracting up to a thousand visitors in one day, Pedersen narrates, “when people reach the top room, everyone is speechless – there is a sudden contact with nature.”

Recycled corrugated aluminium cladding gives the building’s exterior an agricultural quality and creates an ever-changing relationship to the landscape: sometimes reflecting sunlight with a fiery glow, other times disappearing into the grey sky.

Water Tower from Tonkin Liu_Taran_Wilkhu

Image © Taran Wilkhu: CLT provides structure and finish for the bedrooms.

Embedded in place

Acting as project manager as well as client, Pedersen made sure to recruit almost his entire onsite team from the local community. He sought people with an interest and enthusiasm for the project, often finding them through word-of-mouth recommendation and conversations in the pub.

He recalls asking an acquaintance who had done the boxing in around their toilet – “because it was so precise and nicely finished”. Through this enquiry Pedersen met the father and son team, MNB, who went on to do all the woodwork, electrics and plumbing for the tower, “with incredible accuracy and efficiency.”

Local heroes

This sense of enthusiasm and imagination are tangible throughout this project – nothing is wasted or ignored, rather every material, spatial and relational opportunity seems to have been seized upon and nourished with curiosity and delight.

Materials removed from the tank and frame – such as ladders, steel panels and tiebars – were reworked and playfully incorporated into the design. Modifications to the original structure were limited as much as possible. One side of steel cross bracing was replaced with K-bracing, in order to get the CLT box in and to allow access from the stair tower into the bedrooms, and external bracing was added to the water tank to allow a ring of panels to be knocked out for the window.

Other than this, the tank is as it stood.

Water Tower from Tonkin Liu - Dennis Pedersen

Image © Dennis Pedersen: the tower’s glazing faces away from the village, minimizing light pollution.

This article is from issue 3 of Designing Timber magazine. Read more articles from Designing Timber here.