Janna and Seb Laan Lomas explain the ethos behind their self build which blends low energy design and natural building while reducing plastics in the construction and also minimising waste. The level of detail, the decisions made and the careful use of the budget have been instrumental in delivering this fantastic project, which makes a great home for them as well as a site that encourages wildlife.
Interview with Janna and Seb Laan Lomas
This episode explores pushing the boundaries when it comes to sustainable design. Some projects might embrace the use of natural materials but not excel with performance; others will have an excellent performance but have relied heavily on concrete or synthetic plastics insulation. In fact every step of the way there are opportunities to build more ecologically, promote biodiversity, and create a better neighbourhood. You just need to test assumptions, do your own thinking and allocate your budget wisely. Janna and Seb both work within sustainable architecture – Janna is the Founding Director of Grain Architecture and Seb is an Associate at Architype – and this gives them a massive head-start. However, this project does not need to be a one-off.
“In my view, this is entirely replicable.” — Seb Laan Lomas
A dream and a burning desire will normally lead to action
Janna began conceptualising this specific house design when she was only six years old. This long-held dream evolved over thirty years before finally becoming a physical reality. Janna always wanted something traditional looking, and drew inspiration from English and French country houses. She explains how her design also responds to her lifestyle and preferences. She prioritised how light would hit specific spaces and the flow between rooms. There are good sight lines to the outside from specific rooms. The use of natural materials was also really important and she was looking for a ‘perfectly imperfect’ finish internally rather than something minimalist and white!
Seb describes himself as the silent client in this, although he really wanted the project to be a certified Passivhaus.
The site selection considered orientation and community fit
Having a design in mind before you find a site is slightly unusual. It’s normally the other way around. You find the site and then your designs are a response to that site. So there were plot requirements, although the form of the house is fairly simple which made the task easier. One of the main considerations was sunlight so a south-facing site was top of the requirements, both for the house (solar gains and daylighting) and the various garden projects. Access from the north side was also essential to manage the entrance flow effectively. The rural setting provided the necessary space and affordability for the project. Neighbours played a significant role in the decision-making process as well. They engaged with the community early to ensure a supportive environment. This holistic view of site selection goes beyond mere physical measurements. It considers the social and environmental context of the land.
Tri-generational living builds family resilience and financial viability
Two houses were to be built on the site with one home for Janna’s parents, fostering tri-generational living. This setup allows for mutual support as the family members age. Children benefit from closer relationships with grandparents during their upbringing. The project also became more viable financially because they were sharing land and build costs with the older generation. Overall the arrangement builds resilience within the immediate family network.
Design can actively support biodiversity and habitat creation
Biodiversity was not side-lined during the design process. A third of the roof space of Janna and Seb’s house is dedicated to habitats for birds and bats. Open soffits allow wildlife to access the eaves without obstruction. This design choice supports local ecosystems rather than excluding them. They have already observed various species investigating the roof space since the structure was finished.
When it came to choosing the right materials for the house build it was always with an eye on the end of the life cycle. They wanted to ensure they would not poison their immediate environment when the building comes to the end of its life (hopefully centuries into the future!). For example, most of the materials would break down over time and return to the earth. Every decision aims to have a positive impact on the surrounding habitat, which almost treats the building as part of the landscape.
Deconstruction preserves valuable materials for reuse
There was an existing cottage on the site which was beyond repair and rather than demolishing it they were keen to deconstruct it. This process allowed for the careful removal of reusable materials like slates and timber. Windows were reclaimed and repurposed for the solar panel array and potting shed. Even the gas boiler was traded with a neighbour for an e-bike. This method significantly reduced waste sent to landfill. They even uncovered valuable old oak which is no longer commercially available. Although all of this is slower, the extra time required was justified by the environmental and economic benefits. Janna and Seb believe this more sensible and responsible approach should become the default in the industry.
Adequate storage is important to protect reclaimed materials
Storing salvaged materials normally requires a large amount of space and somewhere close by. Janna and Seb already had a good-sized plot, 1.5 acres, and initially used a garden marquee to house the materials, but this did not survive the winter storms! Instead a Polytunnel provided a much more durable and practical option. Without a dry space like this, reclaimed items can quickly become unusable.
The builder had input into the construction approach
When considering what materials the house should be built from and looking at the construction method, Seb compliments Janna on keeping an open mind. Her approach was to allow a wide wall build-up, knowing that natural materials would require this, and then consider the different options and ask the builder how they would like to approach it. For example, they looked at EcoCocon straw panels but there were logistical challenges with getting the delivery to site. They also weighed up other timber approaches and straw bale building, but with Janna’s parents keen that the construction period didn’t drag on they eventually opted for a modular system that their builder was familiar with.
“We ended up with a builder who had a kind of in-house developed timber modular panelised system, which is a Larsen truss system, so two bits of timber, and then it’s held together with plywood gussets and then fully filled with warmcel insulation, airtightness line on the inside.” — Seb Laan Lomas
Screw pile foundations offer a low-carbon alternative to concrete
One of the aims of the project was to avoid poured concrete. Therefore they used a screw pile system that has a seventy per cent lower embodied carbon than traditional concrete slab foundations. Another benefit is that they are fully reusable and recyclable at the end of the building’s life. The contractor was impressed and found the whole approach easier and faster.
Once out of the ground they are using almost entirely natural materials. So there’s a timber floor which is raised above the ground to ensure airflow and prevent moisture issues.
“On the moisture front, whilst we know that these design principles are going to work, we have installed a whole range of moisture sensors throughout the building, and so they wirelessly transmit data from wherever they’ve been installed, of the moisture content and of every bit of wood they’re screwed into, as well as the temperature and the relative humidity at the sensor. So we’ve got them in the floor construction, we’ve got them throughout the wall construction, we’ve got them in the roof, and we’ve got some on some of the internal walls.” — Seb Laan Lomas
The sensors have shown the whole moisture journey of the building to date, and communicate and reassure everyone that this is a safe and resilient way to use natural materials.
It’s hard to eliminate plastics but you can certainly minimise their use
When you’re building a Passivhaus a common approach is to insulate with EPS beneath the slab. Janna and Seb have managed to avoid this because of their alternative foundation solution.
Plastics are also frequently used in airtightness layers, with products such as tapes and membranes. Again, Janna and Seb have thought hard about how they can keep plastic use to a minimum. In this instance they’re mainly using an airtight OSB (SmartPly) which only has a very thin layer of plastic.
“This whole process has opened my eyes to the quantity of plastic in the packaging, which includes the natural materials that we’ve so carefully chosen… It has been quite disheartening at times, you know, several skips worth of just packaging, which when we’ve tried so hard to minimise waste and minimise plastic in the build, and there’s far more plastic that went in the skip than there is that’s gone in the house.” — Janna Laan Lomas
The contractor delivered a watertight and airtight shell, allowing Seb and Janna to take over at first fix.
Volunteer labour has helped reduce plastering costs
After being quoted around £20,000 for plastering the inside of the house (which included materials and labour), Janna and Seb took a different approach. Over one hundred volunteers assisted with the plastering and finishing work. Participants ranged from architectural students to local homeowners and builders. With the clay coming from the existing site the cost savings were substantial compared to hiring professional plasterers. In fact the only outgoings were for food and drink to thank the volunteers for their time, which came to about £400. Another benefit of this approach was that it served as a training opportunity for those interested in natural materials.
Handmade finishes celebrate imperfection and natural beauty
The interior finish is a clay plaster (clay, sand and fibre) that is mixed together on site and applied to the walls. Its texture and feel adds warmth and character to the house while adding a couple of other useful characteristics. The clay plaster regulates humidity and contributes to thermal mass. When formulating the mix Janna experimented with using wood fibre dust to improve crack resilience and it worked a treat. Although time-consuming this approach produces a lovely finish that perfectly aligns with their natural home and is easily maintained in the coming years.
Getting Building Control sign-off can be challenging with natural materials
Using non-standard materials, even if traditional and age-old, presented challenges with getting building regulations approval for Part B (fire safety). Their Approved Inspector was unfamiliar with clay plaster performance data and would not sign it off because there was no data relating to the specific site and use in this instance. However, switching to Local Authority Building Control seemed to resolve the issue because they had had experience of people doing this before. Extensive research and test data were required to satisfy safety requirements. This experience highlights the need for inspectors to understand traditional techniques. So if you’re planning to go down this route, you need to find Approved Inspectors or Local Authority Building Control who are experienced with natural builds. Janna and Seb were a little unnerved by this, but were pleased to find a solution. Documentation is key to proving compliance with safety standards.
Spend money in the right places
Janna and Seb chose to allocate £20,000 to a specially commissioned oak staircase. Not only was this part of Janna’s original dream but it’s a permanent structural element that also defines the home. The design mimics a sweeping Georgian stone staircase but as it was to be built in timber there were a few design challenges. Close collaboration with the craftsman Carwyn Jones ensured the complex joinery accounted for wood movement without compromising the solid oak construction. This decision highlights their strategy of prioritising the building fabric over cosmetic details that can be changed in the future.
A low heat demand allowed them to simplify their heating strategy
Initially they had been looking at an air source heat pump to provide heating for the house. However, they found that it was really tricky to find a good designer and often the systems were way to large for their small heating requirements. The embodied carbon of the whole installation and the impacts of the refrigerant led them to look at other options. In the end they decided to install three 1kW direct electric heaters. This was much simpler and cheaper, and freed up cash to invest in solar PV panels and battery storage. It proves that a fabric-first approach can scale down your energy needs. Building to the Passivhaus standard is a tried and tested approach to delivering a healthy, comfortable and energy efficient dwelling.
Find out more
Grain Architecture – Janna’s architectural practice
Architects Climate Action Network (ACAN)
Alliance for Sustainable Building Products (ASBP)
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