Danny Luhde-Thompson explains why he chose to demolish the bungalow he was renovating, to build a contemporary Passivhaus.

Interview with Danny Luhde-Thompson

After shelving plans to return to his home country of Wales, Danny decided to stay in Harpenden and redevelop their existing 1960s bungalow. Even after modifying some of the internal spaces they realised they were having to live with compromises and some things that fundamentally couldn't be changed. At this point they decided to abandon the redevelopment work and spent the next few years planning a new house on the site of their existing bungalow.

Hiring a planning consultant was an easy decision

Previous experience of the planning process, and knowing that getting permission to build a contemporary home in their area would be challenging, meant that one of their first appointments was a planning consultant.

The consultant went through the Local Development Plan (LDP) ensuring that their house would comply with the criteria. They worked with the architect, taking on concerns from the planners and modifying the plans accordingly, so when it came to submitting their application they had the confidence that there was no real grounds for refusal.

The brief was for a contemporary family home

The key requirements for the brief were that the house should have a contemporary, simple, uncluttered feeling, but still be warm, welcoming and practical for living in as a family. They also wanted a view through the house to the garden, and to use a minimal palette of materials.

While Danny's involvement focused on the fabric of the building, the services and the Passivhaus elements, his wife worked with the architect on the interior finishes and details. 

They sought a specialist team with Passivhaus experience

Once they had planning permission they decided to appoint an architect that had experience of doing detailed design of a Passivhaus. They chose Gresford Architects, who had just finished another Passivhaus building, and used MBC, an Irish timber frame manufacturer, who could supply the passive foundation system and the airtight timber frame shell. 

Their programming and garden design skills were an ideal combination!

A programmer by trade, Danny was able to apply his skills to various elements of the house. When it became apparent their traditional M&E contractor wasn't aware of how to do things differently for a Passivhaus, Danny took over the role. Although a steep learning curve, he designed the plumbing system, and at some point will also get round to writing the programme for the automated external blind system for the windows!

And with Danny's wife being a garden designer, she enjoyed being able to bring her expertise to designing their own garden and was also able to do a bit of experimenting!

The log burner can be used to heat the water

Having a log burner was a feature they were keen to incorporate into their new home, but it did prove a challenge. A minimum of two or three logs are required to make the fire, producing around 8kW of heat output, and Danny didn't want more than 2kW which would be the peak heating load for the house. He managed to get around it by dumping the rest of the heat into the water.

He designed a heat store which lets them run the stove for eight or nine hours before it gets too hot. It links into a solar water heating array and an emergency gas boiler. In hindsight he thinks perhaps an immersion heater might have been better as they wouldn't have to pay the standing charge for the gas. 

The house also has an underfloor heating system in the concrete slab, which they use only occasionally in one area of the house. 

A Passivhaus cat flap was needed

Giving up their several cats just to move into an airtight home was something his family wouldn't consider, so Danny was relieved when he found a suitable cat flap! A hole is cut into the door and the flap is installed with the right seals and screws. It has a large amount of external insulation and its own triple seal system. Apart from the electrical detailing (it has a motor and a secure locking mechanism that need to be powered), it was fairly simple to install.

The simple cube form belies the complicated detailing

Externally the cube form looks very simple and contemporary, but from a thermal point of view it was quite complicated; keeping the steels away from the edges and making all of the insulation detailing work.

“I mean I know it was a bit of a headache for MBC to figure it all out, but worth persevering and that’s one case where I could stand back and let the Passivhaus consultant and the timber frame manufacturer just sort it all out. But yeah, it did take them a few weeks of arguing about it.”

Some elements took inspiration from the Barbican

Danny and his wife took inspiration from the Barbican, and also a particular house in Australia that they both liked. They found a manufacturer who could design them a replica staircase.

The use of concrete work surfaces in the kitchen were also a nod to the Barbican and meant they could have that material in their house where they could feel and use it every day.

Danny's brother builds kitchens and they were able to mock up the entire kitchen from chipboard to work out the final dimensions and gaps between the surfaces before casting it, which they found to be a big help.

If you put in the effort up front, it can all work out well

Danny had a very collaborative team and credits the success of the project to things like the time spent on the design, the architect making sure they weren't making any mistakes with the spaces, and the fastidious attention to detail of the electrician.

Late changes paid off

Despite all the planning there were still two occasions when they decided to make late changes. The first was when the timber frame was going up, and they realised the window in his wife's study would be better if it was taller. Danny says almost immediately someone got out a chainsaw and made the modification to the timber frame, and they placed an order for a new window.

The other change was once the stud wall was up in their bathroom. They thought that if they had an internal window they would be able to use the bathroom while being able to enjoy the views out to the garden. The architect spent many hours redesigning the sight lines to preserve dignity, and it has brought more light into the room and works fantastically well.

Don't rush, and have a good architect

Danny's tips for building would be to not rush into it. Take your time, visit other houses (particularly Passivhaus), and take on board other people's advice.

AECB 30th anniversary conference

The AECB conference is an annual event that considers how a sustainable built environment can help fight climate change. This year is the 30th anniversary and the conference will be taking place 7-8 June 2019 at Oxford Brookes University. Although it's an industry event it's actually a great opportunity for self builders to further their knowledge and learn from the experts.

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Find out more

Visit the website of Gresford Architects

Read more about The Deerings on the Passivhaus Plus website

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