Set within a private residential mooring on the Grand Union Canal in Ruislip, northwest London, TiggColl has completed the Float House. Designed for a family of four with evolving health needs and spanning just 77 square metres, this waterside home is both comfortable and environmentally minded. Featuring a modular substructure and a demountable superstructure, with a focus on embodied carbon and end-of-life use, the architects hope the project will become a prototype for “enjoyable and sustainable living environments” on the water

Design brief

The design brief called for a replacement to an existing canal barge, which lacked living space, suffered from cold and damp conditions and had limited accessibility. The family wished for improved level access and a home that, unlike traditional canal barges, sat above the water. Crucially, the family wished to remain within the cooperative of 35 houseboats moored together in a private and permanent location.

“We wished for a home that was beautiful and practical for a family of four that would also accommodate my future health needs. Starting this new build was a huge leap of faith, but we never gave up hope that our vision was achievable. Thanks to the unwavering commitment of TiggColl and the team of engineers involved in this project, we have a home that has surpassed our dream: peaceful, surrounded by nature, with breathtaking views out across the water.” 

— Phil and Narinda Desrosiers

Built for water

Access to the Grand Union Canal in this location is restricted by low bridges, both upstream and downstream. Due to the absence of a dry dock or quayside, traditional methods of maintenance, such as removing the houseboat by crane, were not feasible. In collaboration with marine and structural engineers, TiggColl developed a unique system of interlocking steel hulls secured by a gantry.

Each of the ten hulls can be individually towed from the gantry and lifted to the canal bank for maintenance. Typically, if a boat's hull requires maintenance, it has to be moved to a dry dock. This system makes maintenance a simple and cost-effective affair. The superstructure above the hull is made of prefabricated glulam spruce modules with projecting bays over the bankside that house the kitchen and children's bedrooms. 

“One major problem when designing floating homes or any structure on water is the requirement for regular maintenance, without which the typologies can quickly degrade! Regular maintenance can be a laborious and expensive affair, so our design solution sought to address this.”

— TiggColl

Envelope

The external elevations of Float House are clad with FSC-certified Accoya timber slats, a sustainable and durable material that was selected for its waterproof qualities. The timber has been intentionally left untreated to allow natural weathering and avoid chemical finishes, making future recycling easier.  The timber superstructure is protected by a GreenCoat PLX standing seam metal roof, coated using rapeseed oil and bio-based technology rather than more environmentally harmful chemical treatments. This provides durable weather protection while maintaining full recyclability.

Floor plan

TiggColl describe the brief for the floorplan as “ambitious,” the clients requested an open-plan living space, a main bedroom suite, two children's bedrooms and a shared family bathroom within a plot size of 4 x 20 metres (a size dictated by the canal width, passing distances and the length of the mooring). They achieved this, and more. Inside, the Floating House floor plan has been cleverly designed to maximise use of space and natural light. Cantilevered window bays create additional worktop spaces in the kitchen, and form the basis of the beds in the children's rooms. These also feature integrated ventilation panels and support solar shading, while defining the bankside elevation of the home. 

Sustainability

The home is heated by a boiler powered by converted used cooking oil, which has a lower embodied carbon footprint than a typical gas or diesel boiler and is estimated to produce approximately 90% fewer emissions. High levels of insulation, combined with underfloor heating throughout the 77 square metre home, allow the system to operate at a lower temperature than a conventional radiator-based heating system, improving energy efficiency.

The building itself has been designed to be fitted with a PV array along its 20 metre-long south-facing rooftop. “This was a driving factor when developing the massing to maximise direction and pitch for solar panels,” the architects explain. “This potential future requirement was also considered in the loading criteria and general superstructure design.” Solar was only omitted at this stage due to budget constraints rather than design or client desire.

Embodied Carbon

The design prioritised a low-carbon superstructure made from engineered timber to offset the higher-carbon floating foundation required to provide buoyancy. The superstructure consists of optimised spruce glulam portal frames, with timber joists and OSB diaphragms spanning between them. Compared with a conventional steel frame, this approach significantly reduced embodied carbon while allowing the structural elements to remain visibly expressed within the architecture.

The frame spacing, section sizes and diaphragm configuration were also carefully refined to minimise material use while meeting structural performance requirements, including resistance to wind loads and the unique tilting movements associated with a floating structure.

Simplified maintenance

Unlike more typical canal barge designs, which can be expensive and carbon-intensive to modify, this project is allows for straightforward and targeted changes or repairs. Only the elements that require adjustment need to be altered, and modifications can be carried out using simple tools by a two-person team. This approach reduces resource use, operational complexity, and associated carbon emissions over the building’s lifecycle.

Modular and demountable

Float House was designed to minimise disruption to the canal environment. Working with Bucklands Timber, TiggColl adopted a modular construction approach, creating an exposed timber structure throughout the boat. Once the floating base was assembled and launched, the structural frame was installed quickly on site, reducing the amount of work required on the water and limiting disruption to the surrounding canal community. This modular system is demountable: Both the floating hull and the superstructure can be dismantled, relocated and reused, helping to extend the home's lifespan and minimise material waste.