Jon Martin and Noreen Jaafar have built a Passivhaus-certified treehouse in the centre of a Cotswold market town, taking advantage of a woodland site that no one else could find a way to develop on — in small part down to a 5m drop from front to back, and in large part down to the 27 protected trees that sat on the plot.

  • Homeowners: Jon Martin and Noreen Jaafar
  • Project: Passivhaus Self Build
  • Location: Dursley, Gloucestershire
  • Size: 200m2
  • Build time: Nov 2012 – Nov 2016
  • Plot cost: £85,000
  • Build cost: £308,000

Jon and Noreen invited architect Tomas Millar of Millar + Howard Workshop to visit the plot with them and discuss ideas. “When he arrived he was straight onto one of the trees,” Jon recalls. “He shimmied along it and said: ‘That’s the view you want.’ His design was sympathetic to the land, right from the outset. Other people had tried but they were all for felling the trees and putting a building in the middle, which is not what we wanted to do.”

Key to the final design is the steel frame upon which the aptly named Treehouse sits — it means the building is suspended from the ground and gives the impression that the house floats among the canopy.

The Treehouse is made up of three boxes, the upper two clad in untreated larch and the lowest level, which contains a workshop for Noreen’s ceramic business, clad in stainless steel to reflect the surroundings. It also features sheltered decking around the middle floor on three sides of the building, providing more usable space — some of Noreen and Jon’s favourite in the entire building.

the Treehouse's terrace off the first floor

The first floor has covered decking on three sides, providing more usable space for Jon and Noreen and allowing them to almost touch the trees that surround the Treehouse

The design was, however, initially rejected by the planning department. “It was refused because of the trees and not the design of the building,” explains Noreen. “We had to prove to planning how we would protect the trees. We had to have all the roots mapped out and special matting that protects the roots during the building process.” Permission was granted unanimously on appeal.

The design called for the Treehouse to be supported by 16 slim screw pile foundations, bored 10m into the ground by specialist equipment that would minimise the impact on the roots and nearby listed buildings. The company that manufactured the steel frame then came on site for three days to explain the erection process to Jon and a friend he’d roped into helping, before the pair tackled the job themselves.

Knowing that they had a finite pot of money to work with, and were limited by the site’s trees and slope, meant that Jon and Noreen were facing constraints at nearly every turn, but this brought out not only the best in the house design, but also the procurement. “Like it did with the physical restraints of the site, I think having budgetary restraints made us more imaginative and creative,” says Noreen.

The internal spaces include picture windows to frame the listed trees that surround the Treehouse. You can also see the slate floor, which was bought from ebay and stored on site for two years before it was installed

For example, two types of flooring are used: a slate floor bought off ebay from a Rolls Royce dealership that came in at a quarter of the cost they had been quoted for new (and which was stored on site for over two years before being installed); and a repurposed sports hall beech floor, with the markings of basketball and badminton courts still visible. Outside, the decking is made up of grilles that Jon got for free when a local diesel engine factory was demolished.

There were certain aspects of the build that they had to spend extra on, namely those to secure the Treehouse’s Passivhaus certification, including triple glazing throughout and a mechanical ventilation with heat recovery system. They also employed the services of an energy consultant, who worked closely with the architect and the structural engineer to ensure the home was as airtight as possible.

The Treehouse is accessed via a suspended walkway,
made up with grilles from a former local diesel engine factory

Jon and Noreen’s goal of living entirely off grid hasn’t been fully met (a private spring water source on site, found by Jon, means that to avoid contamination they had to connect to the mains sewers), but with no mortgage and bills of just 30p a day for water rates, they are enjoying an entirely new standard of life in the Treehouse.

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