Toby Diggens explains what it takes to meet the requirements of the Living Building Challenge, and working to the standard when renovating an existing building.
Interview with Toby Diggens
Toby Diggens is a landscape architect, conservationist, and founder of Digg & Co. In our first podcast with him we discussed how to be a good custodian of the land you own. In this episode we’re looking at his barn conversion that’s taking on the Living Building Challenge.
The Living Building Challenge is a holistic framework
It aims to create a building which is as closely tied to its ecosystem and surroundings as possible. It’s not about delivering a ‘slightly more sustainable’ building than standard building techniques. It considers how a building exists in its ecosystem, and how it can be made positive to that ecosystem, rather than neutral or negative. While the framework includes things like a ‘red list’ of materials that you can’t use, it’s about far more than the science and technology of the building construction.
Another aspect to the framework is its ‘offsetting’ concept. Because Toby wanted to develop an existing building, that reduced the offset required. But the concept also factors in the type of land being developed, and the rural farmland ‘zone’ where the barn stood meant some dedicated ecological restoration was also required.
The barn before the conversion
The standard is challenging, but offers flexibility
Renovating an existing building does add some complexity to the Living Building Challenge. The superstructure of Toby’s barn required breathable building fabric solutions, so effectively pushed him towards a more ecological approach anyway.
Another reason that Toby chose the standard over Passivhaus or BREEAM accreditation is that it gives you the opportunity to argue your case for decisions made. You have to meet the general principles of a modern ecological building, but can also justify why you’ve chosen a particular detail or bought a particular product.
The balance between traditional construction and modern building regulations is interesting
While there are few buildings accredited to the standard, humans have a long history of dwelling on the land and developing traditional building techniques to create shelter. The complexity of the Living Building Challenge comes from ‘fast forwarding’ those traditional techniques to make a modern building. Toby found he was able to hold to traditional principles throughout his project, and it really spurred him to think about details – even down to recycling the materials that came out of the building.
Sometimes compromise is necessary
Only one material choice prevented Toby’s project from using all ecological materials. Expanded polystyrene (EPS) insulation was required under the concrete raft floor slab, because a suspended timber floor with natural insulation would have impacted on the overall volume of the space and reduced the upstairs floor heights too much. The mitigation for the insulation choice was that the raft slab itself used recycled fly ash concrete rather than virgin concrete.
The Living Building Challenge was a positive towards achieving planning permission
Several factors helped Toby to achieve planning permission. An application had previously been refused to turn the barn into holiday lets, so it was good that Toby could show the conversion would be a place for him to live and work. In an area where many people commute to Exeter, it was a significant positive to be applying for something that would create community and support local farming activities.
A ‘living building’ includes aspects of biophilic design
The Living Building Challenge references biophilia throughout its literature. For Toby, biophilia was an integral part of the design process. He had always dreamt about having somewhere in a house with a big-enough glazed area to grow plants, and the barn’s structure allowed him to create a double-height atrium.
But biophilia is more than just plants in the home. It also means designing as if your environment is your outdoor environment. The ‘flow’ of a place creates a calming environment as much as function does. When it is done right, it’s very aesthetic because it makes you feel right about your surroundings.
Trying to do the project quickly could have led to bad decisions
Toby avoided aggressive timescales, which helped in terms of managing costs. A faster timescale would have needed more people or more materials on the job, and costs would have gone up. He also feels it was important to see the design emerging and then decide what next, rather than forcing solutions onto an old building.
Extra time also allowed the opportunity to analyse the project’s finances and see where any design decisions might need to be changed. A key learning point for Toby is that there is never one way to finish a project. There are lots of ways around challenges, if you have the headspace to think things through and design a solution.
Setting your stall out is essential for creating an ecological building
Toby was clear with everyone involved on the project what he wanted to achieved, and that there could be no corner cutting. For example, a stone wall fell down and Toby insisted that it be rebuilt in the way it was originally built. His builder was incredulous, but days later was photographing it as something he was really proud of.
The logic of sourcing materials locally simplified things, in some ways. The barn features a lot of ash, because local woodland was being cut down to try and get ahead of ash dieback. Toby has friends with a company that uses native hardwoods, and they helped him to get the ash milled up. It really contributed to the feeling of the house being tied to its local landscape.
Managing waste led to interesting design solutions
As part of briefing the team clearly, Toby asked that larger offcuts and scraps of materials be saved rather than disposed of. Most people would see such collections of material as waste, but they were a resource for the project team. Design details emerged from having this collection of materials, and there were occasions when the team could marvel at what had been achieved out of a pile of ‘waste’. It took a lot of work to keep people focused on this, but it led to a lot of satisfaction with the finished result. And during the project, Toby never had to hire a skip.
Being a working farm also helped in terms of managing waste. Pallets are now used for storing hay on, and there is always a use for offcuts of timber. Local farming department stores have schemes for recycling silage wrap, so Toby was able to give them the plastic wrap from insulation and other materials.
Keeping momentum is essential – and can require some ruthlessness
One of the main things Toby has learnt is that momentum is everything. If you lose it, regaining it is very difficult. As part of project managing his build, he found he had to be ruthless in keeping stuff arriving to site and keeping people engaged with jobs that moved the project on. He worked hard to make sure people were well-briefed, had the right drawings in front of them, and that he able to answer any questions about any details.
The water requirements for full Living Building certification are demanding
Toby hasn’t achieved the drinking water requirements that need to be met for full accreditation. He would have to spend £20,000 or more on a tank to collect rainwater, and a UV filter. He would like to use his own water rather than the mains, but a mains connection will always be required to provide a top-up if required. If money was no object then he would install the system to get full ‘Living’ certification, but the project can still achieve ‘Petal’ certification.
A log burner is allowed by the Living Building Challenge
In his rural location, Toby has a sustainable source of wood to fuel a log burner. The Living Building Challenge views this an acceptable ecological approach, as it ties in to management of the land. Also, compared to a densely populated urban scenario, a log burner is not very damaging from the perspective of particulate pollution.
As well as the log burner, Toby has electric underfloor heating, but it hardly ever comes on because of how well insulated the house is.
Living Building certification is awarded only after as-built checks
Design details have to be submitted, showing things like the thickness of insulation, and an airtightness test is required. Energy use over a year is also submitted.
The version of the standard that Toby worked to required the house to be able to produce 105% of its energy, for which he has a solar system and a Tesla battery, as well as solar hot water.
Retaining character in old building means looking at features you’ve already got
It can require some foresight, but developing a design around existing features really helps with keeping character. For example, Toby had a strange opening in an existing wall that had a lintel about 12 feet off the ground. He was looking for ways to form a doorway without causing the wall to collapse, and suddenly looked at the opening and thought about making that the door. So now he has a 12-foot-high door with an original oak lintel.
Creating a ‘living building’ is a massive undertaking
Toby can’t see the Living Building Challenge exploding in popularity in the self-build community. While it is a wonderful concept, he sees it as something better suited to bigger projects where there is more resource available for project management and dealing with accreditation. Many self-builders already make such a lot of sacrifice, perhaps living in a caravan on site while a project progresses. It’s very self-willed to achieve the most important things of getting the project finished and getting into the house. You have to be exceptionally committed to also achieve all the targets of the Living Building Challenge.
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