Warehome: Designing the sustainable homes of the future

Did you know that buildings account for 39% of all global energy related carbon emissions? From the energy used in central heating to the materials used in their construction, our homes are a huge contributor to our carbon footprint. So how do we create sustainable homes for the future? Architectural firm Warehome, based in East London, is trying to answer that question.

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You know you have to cut down on plastic, use less water and switch to an electric car. But have you ever considered the role your house plays in living more sustainably? We’re not just talking about adding solar panels. The concrete, the bricks, the mortar used to build our houses, even the contents, all have considerable impact on the environment. In fact, buildings account for nearly 40% of global, energy-related carbon emissions. We can’t stop building houses, so when it comes to being more sustainable, what can we do? How do we create homes that work for us and the environment? Joe Stewart is the founder of Warehome, a small architectural practice based in East London that specializes in low-energy sustainable homes and is supported by PTC’s strategic partner, INNEO UK. His own house in East London is the project that launched him on this journey back in 2012, designing and building Warehome’s first home.

Sustainable, interesting homes

Unable to afford a place to live in London, Joe ‘stumbled’ upon the site and the opportunity to design something with the level of comfort he felt he deserved, as a hard worker. With a love of architecture, he has always been in design, engineering and ‘tinkering’. ‘The key here,’ he says, ‘is we’re building. We’ve got people building for themselves, so they care. It has to be a sustainable development and it has to be interesting. For a standard, two-up, two-down project, Warehome’s not the best match, as the amount of time spent on the details and getting the design just right would be too costly. We’re not facilitating a utilitarian approach to building a building. We’re creating future memories.’

Passivhaus: a thorough approach

Warehome specialises in Passivhaus, a German approach to how design works, both thermally and holistically. It considers how much energy you need to heat the house, how much energy you need to cool the house, where you need to put the windows. ‘It’s a very thorough, typically German approach to assessing the design, rather than just building what looks pretty, and then going “I hope this works”’. For example, in Joe’s entrance hall, there is glazing on the north side, bringing a lot of light into the space, which is only a few square metres. On the same level is the main bathroom, accessible for visitors, where he protected the floors and the walls from abrasion from shoes, chemicals, and water, with a water-based polymer. The material has a seamless surface, with a cloudy grey patina like a concrete finish, but with less embodied energy.

Temperature control

In the case of Joe’s house, the application of Passivhaus meant there was no heating system except for body heat, such as fridge and freezer, and the sun from the outside. In the winter, he and his family heat it themselves. For the summer months, it was key to shade the house correctly. With a Swedish wife, he was naturally influenced by Sweden, but also Japan, and certain areas of Europe, where ways of working with smaller, tighter spaces, and functionality and separation of rooms, feed in well. ‘We see a lot of the Lagom principle coming into how we work, meaning “just enough” or “just so”. It’s essentially a not-too-much, not-too-little Goldilocks position.’

Quality not quantity

Half a floor down is a spare bedroom and wet room, so guests feel they have their own space, as they’ve come in the entrance and down, whereas the rest of the house is up and out of the way. The family also use it in the summertime when it is naturally slightly cooler. The bedroom is the same footprint as above. ‘It’s a modest house. There’s nothing really lavish, but we’ve got good space.’ The key to making it feel bigger is the dual aspect of glazing both sides, so light comes through and dark spots, which can often make a space feel smaller, are avoided. Every wall is used for storage. Entering through the wardrobe space, rather than coming in and seeing a wardrobe, gives the best perception of space. It’s all about the quality of every meter squared, not the quantity.

Cross-laminated timber

Timber has been used to create structures for thousands of years, so 30-year-old CLT, one of the key materials, is relatively new. It looks like a standard block of wood you might see in a timber merchant, but it’s gone through a process of being glued together and cross-laminated, so it gets inherent strength in multiple directions. This massive piece of wood can be cut into pretty much any shape and the benefit is it allows you to get some thermal mass. When you’re trying to keep your house warm, you want to be able to store that energy. If you want to keep it cool, you want to store that energy. The timber does it without the embodied energy of concrete, or steel, but allows for some of that mass energy to give stability, resistance and flexibility, pertinent when you consider the earthquakes in Turkey.

Embodied Energy

In layman’s terms, embodied energy is the amount of energy it takes to create something. ‘Steel’ is created in a forge, so there’s a lot of heat, energy going into bending, fabricating, drawing materials out. A tree grows itself and we cut it down. There’s energy in cutting it and transporting it, but it’s far less than having to dig something out of the ground and apply heat pressure to make it a usable material.’ Warehome’s drawn to timber as a low-embodied-energy material that also has the potential to offset energy; it’s called carbon sequestering. In managed forests, where they’re replanting appropriately, it’s possible to capture some of the carbon because it gets stored in the building. ‘It’s this lovely cycle of once you’ve used it in the building, it can then downcycle to the next appropriate material, right the way through to being pelleted and burnt, then that carbon gets released back into the environment and starts the whole cycle all over again.’

Is CLT safe?

People will ask if this is as safe as building in a traditional manner. ‘Concrete and brick have stability, mass, that feeling of security, but the structural requirements are the same. Arguably, the lighter weight the structure, the less it must work and the better it is.’ In the UK, we currently don’t have the issue of earthquakes, where we’ve seen brick, block and concrete buildings devastate communities. Studies in Canada and Australia are showing CLT is very predictable. ‘It’s easy to tarnish timber with a bad name because it might be weaker, or burn, but that’s not the case. The UK doesn’t have a flourishing timber industry, so politically, there isn’t the want to say it’s a wonder material, which gets in the way of a sustainable material that’s been used for thousands of years to create homes. It’s a safe choice if it’s designed right. That’s the key to all technologies.’

Style without tiles

Joe’s wet room is adjacent to the spare bedroom and has an ensuite feel. The open shower, 2.7 meters by 1.6 meters, feels spacious and provides another opportunity to choose better materials. There’s the same seamless floor, used up the walls, but rather than porcelain tiles with grout, which have high levels of embodied energy, he’s used a water-based, VOC-free polymer. Designed for swimming pools, it’s a more sustainable choice. It’s not the cheapest, but at the end of its life, less energy is lost as the thin layer can be ground off, much easier to remove than broken tiles and grout. ‘Materiality is often overlooked, because the standard approach is “well, we’ll put tiles in the bathroom”. Water management means there are atomizers on taps, everything just to reduce. ‘In design, it’s “reduce, reuse, recycle”, and that first R is often lost. If we can reduce the amount of water, heat, or materials, that’s a great start.’

The personal touch

On the full floor above ground, there is a snug, 2.5 meters wide by 3.5 meters. The distance between sofa and TV is perfect, and the TV’s craftily hidden in a frame, so it looks like a picture when it’s out of use. ‘When you’re trying to get your life into a smaller space, it’s a balance to make sure your own personality is included in the design. You can start with the structure, and how it works, considering the sustainability, where the windows need to go to make it work well, what materials to use within the build-up. But how you dress it, how you finish it, is critical.’ Not everyone has the luxury of being part of process from the start, understanding how light moves around the space. Joe implores people wanting to build their own home to use a VR headset and walk through the house in a virtual space.

Virtual space

Over the last seven years, more and more technology has come into house design. Warehome works with modelling, to get highly realistic VR and 3D models, both for manufacturing, so projects can be made off site, be it with cassettes, which are prefabricated walls, CLT or glue-lam. It also then allows them to take the client through that journey with a headset, see how they can use it differently. They can stretch their arms out and not quite touch the walls but get a real understanding of how much space they have or haven’t got. They use VR and 3D modelling throughout the design process, from early concept, where figuring out window placements, or room configurations, with a photo-realistic impression of what a client’s home will be. ‘We have their exact speakers, sofas, joinery. Maybe they won’t have plants and whisky bottles on the side, but it’s adding that personality. Clients can fall in love with their place before we’ve even built it.’

Creo the hero

To design and model their bespoke buildings, Warehome needs a program capable of parametric modelling. They’ve chosen to use Creo, PTC’s 3D computer-aided design software. Brian Thompson, who heads up PTC’s CAD division, says Creo’s use within architecture shows how versatile it is. ‘We’ve had a robust business, for decades, within the architectural segment, mostly in the development of aesthetically beautiful architectural components. We have a broad array of customers that do that kind of design in Creo, but Warehome is taking it much further. They are using technology fundamentally designed for the discrete manufacturing industry, and applying techniques associated with traditional product design, in the design of architectural structures. That is creating a tremendous amount of precision and detail.’

Fusion reaction

Warehome’s use of Creo gives them excellent foresight into manufacturing and construction costs, and they’re starting to use standardized components in the manufacture of their products. There are examples of customers building very large structures with Creo, some extreme. On PTC’s website recently, we announced our involvement in a highly significant development in the world of fusion: an experiment that created positive energy because of a fusion reaction at the US National Ignition Facility. ‘We’re talking about a massive engineering structure, all developed in Creo. Every component is designed from a purely engineering point of view, they know every detail about that assembly, though as you look at it, you could very well think of it as an architectural project. So cool and nice to see someone in the more traditional architectural domain taking those concepts and applying Creo in similar ways, on a different scale and with a different design in mind.’

Creo and Passivhaus synergy

For clients looking for a property that’s a bit different, Warehome’s main forte is Passivhaus, a low-energy, innovative solution. As they’re dealing with both design and materials for the construction, they become more involved earlier than traditional architects would. ‘Of course, to do that, you need control of the project, and visibility and control over the bill of materials, something that’s tough to fully grasp, fully lock down, within the engineering world. Creo helps them with this. This is one of the great strengths of applying engineering discipline to a project like this. It has been a challenge for design engineers from the beginning, especially in today’s world, where there’s a lot more awareness of the impact of the material choices that you make, in the sustainability, or environmental impact of the design you choose to eventually implement in your product.’

A great fit

Creo has been developed to give engineers the freedom to try out a variety of material choices and apply different design techniques, to help them understand more. ‘How much material are we applying here? Can we improve the efficiency of the use of materials, to reduce the design’s carbon footprint? That’s at the forefront of what design engineering systems can do. It’s another good reason why you have a strong connection between a company that wants to do environmentally conscious structure design, or home design, with Creo. The fundamental strengths it has in the complete management of all the components, understanding of all the materials and how all that impacts the overall design in terms of environmental impact, is something that Creo was strong in, anyway. It’s a great fit.’


Thanks to Brian and to Joe for showing us around his home, the first-ever Warehome project.

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This is an 1860 production for PTC. Executive producer is Jackie Cook. Sound design and editing by Oli Geu. Recording by Hannah Dean and music by Rowan Bishop.

Episode Guests

Joe Stuart, Owner, Warehome

More About Warehome

Brian Thompson, Divisional GM, CAD Segment, PTC

More About Creo