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  • Writer's pictureLaurence Becker

The Sheds: Charting the Birth of the UK's First Passivhaus Premium Home - Part 2

In the first part of my journey, I immersed myself in the world of Passivhaus, overcoming the hurdles of the BRE Passivhaus designer course and redirecting my path towards the ambitious task of designing and certifying a Passivhaus.

Enter Duncan, whose project to create the UK's first Passivhaus premium home became a collaborative endeavour. Our initial meeting in Duncan's London townhouse laid the groundwork for an extraordinary partnership, and as we reviewed plans a month later, the complexity of the challenge became apparent. Undeterred, we strategically divided responsibilities—I focused on construction drawings and meticulous data input for the Passive House Planning Package (PHPP), while Duncan tackled technology and renewable energy aspects.

The PHPP, though user-friendly in conventional contexts, posed a unique challenge for our extraordinary project, demanding intricate data input for the creation of a truly exceptional home. And so, fuelled by determination and a shared vision, our journey continued towards the realization of the UK's first Passivhaus premium home.

The first hurdle in our project was deciding on the construction method. The concept architect had outlined a SIP build in the approved design, and Duncan was enthusiastic about it. Contacting timber frame manufacturers with rough plans revealed that most found the proposed roof spans and overhangs impractical without compromising the layout. After several setbacks, we turned to SIP company 'A' (Not their real name!).

However, the catch with any timber frame company is that they require a completed set of drawings to work on their timber frame design. Given previous hesitations from other companies, our caution increased. We requested SIP company 'A' to provide an idea of how they planned to structurally support the panels, but after months of back-and-forth, it became apparent that it was beyond their capabilities. Despite delays, a recommendation led us to another firm that proposed a sensible solution, rekindling the project's momentum.

As previously discussed, Duncan's layout adjustments posed an additional layer of complexity, pushing the retaining further back to create more space on the lower floor. This structural shift meant the joint of the two floors now sat in the middle of the kitchen. Initially considering posi joists for the floor, we aimed for the ideal space they would provide for services. However, with the joint in the middle of the kitchen, concerns about movement and cracks in the tiling led us to design a steelwork frame to hold hollowcore concrete planks, ensuring stability and addressing our unique challenges.

Foundations proved to be a straightforward element, with Duncan opting for Isoquick, an insulated raft foundation. A last-minute decision switched the reinforced concrete retaining wall to insulated concrete formwork (ICF) for ease of construction and continuity of insulation.

The Sheds foundations and steel frame
The Sheds foundations and steel frame

Once the materials were chosen, we inputted all initial data into the Passivhaus Planning Package. Although the window manufacturer had yet to be selected, generic triple-glazed windows were used for draft calculations.

Fortunately, the initial data input looked promising, setting a positive tone for the next phases of the project.

PHPP Verification extract
PHPP Verification extract


Looking ahead to Part 3, we'll delve into the crucial steps of appointing the Passivhaus assessor, navigating the intricacies of modeling such a complex structure in the Passivhaus Planning Package, and finally breaking ground on site—all while being under the watchful eyes of Grand Designs. Stay tuned for the next chapter in our journey toward crafting the UK's first Passivhaus premium home.


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