A Guide to Sustainable Architecture

When we think of technical standards, there are many ways to judge sustainable design. This can lead to confusion, but it’s helpful to set out the key similarities and differences between these different standards.

Mandatory Standards: Building Regulations and the Future Homes Standard

Building Regulations (Part L, F & O) focus on legal minimum requirements for new homes in England. This includes considerations for insulation values, ventilation and limiting overheating risks. Whilst many older houses do not meet these standards, new works to existing homes can also trigger the need for insulation improvements to be made, for instance.

Building Regulations are seen as the absolute minimum standards required for new houses. The Future Homes Standard, which comes into effect in 2027, will better support more sustainable homes being built.

Performance and Design Frameworks

Going further than minimum standards, the below frameworks can be used to help benchmark performance and achieve low running costs and a low carbon impact on construction.

Net Zero Carbon Buildings Standard

A new standard launched in 2026, this is an industry led framework which covers both operational energy and embodied carbon. It is a built standard, meaning a building needs at least 12 months of actual performance data to become third-party certified. It has been developed to bring together disparate standards into one single voluntary requirement.

Passivhaus

Passivhaus has been around since 1996 and is a rigorous approach to reducing operational energy. This includes a superinsulated building envelope, with high levels of airtightness and triple glazed windows. Achieving Passivhaus standard requires not only initial design involvement but rigorous on-site involvement too, to ensure the standard is met.

Passivhaus currently only has requirements for operational energy, with embodied carbon reporting not required for its certification. This has meant historically that less sustainable materials have been used in Passivhaus construction, though this is changing.

LETI Benchmarks

The London Energy Transformation Initiative (LETI) has excellent guidelines on designing highly sustainable buildings. Their Climate Emergency Design Guide, released in 2020, gives standards across building types for water use, operational energy and embodied carbon. Whilst London is in its name, it’s used widely across local authorities across the country in their sustainability requirements.

RIBA 2030 Challenge

The Royal Institution of British Architects (RIBA) has developed the 2030 Challenge, which has stepped-over-time performance targets. Broadly, these include decreasing operational energy, embodied carbon and potable water use, plus improving health and wellbeing through building fabric choices.

Living Building Challenge (LBC)

A rigorous green building standard, LBC aims for immense change through regenerative design. This involves designing buildings which give more benefits to the environment than detriment they create. To achieve certification, over 12 months of monitored operation a project must meet the performance categories (‘petals’). These include generating more energy and water than the building uses, restoring ecology, creating optimum human living standards, avoiding common materials containing toxic chemicals and supporting equal access.

EnerPHIT

Developed by the Passivhaus Institute, EnerPHIT is a performance standard based on Passivhaus for retrofitting existing buildings. Due to the challenges of working with older buildings, such as existing structural thermal bridges and layout constraints, EnerPHIT slightly relaxes some of the standard Passivhaus criteria. Despite this, EnerPHIT delivers significant operational energy savings and acts as a good standard for deep retrofits, transforming draughty houses into efficient homes.

Alongside the more technical requirements, there is also the way buildings are built and feel.

An often overlooked part of sustainable housing design is the integration of natural materials. However, as operational energy (the energy you use in your home) has become more efficient, the carbon impact of the materials now makes up a bigger part of what makes an environmental home.

Defining Natural Materials

• Natural materials (also called biobased, organic or regenerative) are those made from plants, animals, earth or minerals which need limited processing. Their sources are renewable and biodegradable.
• Examples of natural materials include timber, straw, paper, cork and stone, which can be used for cladding, insulation, internal finishes and structure.
• Examples of non-natural materials include concrete, steel, plastic and synthetic insulation.
• Natural materials tend to have a lower carbon footprint than their synthetic counterparts, due to their lack of processing energy and their ability to absorb (sequester) carbon from the environment while they grow.

Beyond Carbon Impact

More than simply being low carbon, natural materials are more breathable and have lower VOCs than man-made options, which means they also create healthier buildings to live in. It is a win-win.

One final consideration with building environmentally friendly homes is modular construction. Modular construction is a building method where structures are made in pieces (or modules) inside a factory. Modular design can help decrease the delivery impact of a building and reduces material waste considerably.

Why Studio Bark work with Natural Materials

“We work with natural materials as part of our efforts to follow regenerative design principles. We push the specification of bio-based materials, as a significant way to limit a building’s carbon emissions. We hope to empower other designers to do so too, through sharing what we learn from our experience”.
- Hannah Towler, Associate Director.

One route to building environmentally friendly homes is modular construction. This is a fabrication method where a building’s components are made in pieces (or modules) to be put together like giant building blocks. This shifts much of the construction process away from the unpredictable environment of a building site, into a controlled environment such as a factory. Modular design can help decrease the environmental impact of a building and reduces material waste considerably.

Radically Reducing Waste and Emissions

Because modular construction generally uses more precision engineering, less tolerance is needed in material ordering than in traditional construction, which has to account for uncertainty and breakages. This drastically reduces the material wasted.

Creating ‘building blocks’ off-site also significantly reduces the number of delivery vehicles travelling to site, decreasing the carbon emissions associated with transport. This also results in less disturbance to ecologically rich sites.

Flexibility and the Circular Economy

Sustainable modular systems are designed to be adaptable. Because spatial needs change over time, the system should provide the flexibility to seamlessly detach, modify, or expand the building's footprint without the need for wasteful demolition. Good modular construction supports this through 'design for disassembly,' allowing components to be carefully dismantled and repurposed with minimal waste.

Studio Bark’s Approach to Modular Construction

At Studio Bark, if we choose to build with a modular system it means not compromising on our use of sustainable and natural materials. That’s why we developed our U-Build system, which is now a not-for-profit company in its own right.

U-Build is designed for adaptability and circularity, it’s easy to construct and dismantle with no specialist skills. It’s made using natural materials whilst being compliant with UK building and fire regulations. The system has a third-party verified EPD, which details the data on its environmental performance.

Planning Policy Breakdown

Whilst gaining planning permission shouldn’t be the only reason to choose to design eco-architecture, it is a positive that the planning system incentivises environmentally friendly design by rewarding applications with good sustainability credentials with an increased weighting towards approval.

The New NPPF (National Planning Policy Framework) contains several clauses that award "substantial weight" to planning applications for sustainable projects. Following the August 2026 changes, there is a whole section of the framework that focuses on sustainable development. Here are Studio Bark’s take on some key policies:

Policy CC2.2: Energy Efficiency of Buildings

A proposal that improves the energy performance of an existing building or integrates renewables into a proposal attracts substantial weight in its favour in the planning balance.

Policy CC3.2: Climate Change Resilience

Proposals which are designed to adapt to climate change including (but not limited to) flood-resilient construction, green roofs and overheating mitigation also attract substantial weight. This rewards futureproof design beyond just energy use.

Policy DB3.5: Outstanding or Innovative Sustainable Design

A policy that is well known at Studio Bark (Paragraph 139 in the previous NPPF), this passage sits within the design section of the new NPPF which reinforces the idea that sustainability and design quality are intertwined. It rewards genuinely innovative sustainable designs “which help raise the standard of design more generally in an area “ with substantial weight.

Tipping the Planning Balance

Because these policies direct decision-makers to give substantial weight to sustainable proposals, those benefits feed directly into the balancing exercise under Policy S4 (for proposals within settlements) or Policy S5 (for those outside), which sit beneath the overarching presumption in favour of sustainable development in Policy S3. The practical effect is that strong sustainability credentials make it harder for a decision-maker to conclude that the harms of a proposal substantially outweigh its benefits, tilting the balance towards approval.

Orchard House: A Fabric-First Approach in the Green Belt

Orchard House is a family home on a Green Belt site, designed to deliver an exceptionally low-impact, high-performance dwelling that actively restores its landscape.

Approved under Paragraph 84 for its outstanding architectural and environmental merit, the timber-framed home is shaped by a fabric-first philosophy, surpassing RIBA 2025 targets and nearing the 2030 benchmark with both low operational energy embodied carbon.

The house is built on a low-carbon foundation system using recycled-glass aggrregate. The timber framed structure is filled with blown cellulose insulation and wrapped in wood-fibre.

By integrating natural ventilation, triple glazing and an air source heat pump backed by solar PV, the home maintains a comfortable and stable temperature year-round without reliance on a mechanical ventilation with heat recovery system (MVHR).

A commitment to hyper-local circularity guided material sourcing, including locally sourced larch cladding and parquet flooring milled from a condemned ash tree felled on the property.

Beyond the building envelope, the scheme delivered measurable biodiversity net gain by reviving the site's neglected former orchard.

In addition to safeguarding a rare local pear variety and mature boundary trees, the project integrates bat roosts within the open timber cladding, incorporates permeable paving, and introduces native night-scented planting and intact hedgerows to support local wildlife corridors.

Oolite House: Low-Energy Architecture in the Cotswold Hills

Oolite House is a three-storey family home embedded into the Cotswold Hills designed to combine family living with low-energy architecture.

Situated within a conservation area, the building sits quietly in the hillside where multiple conventional proposals had previously failed. The project adopted a site-first approach, utilising the void left by a failed garage structure, crushing the existing concrete for reuse in groundworks and salvaging local stone for wall repairs.

Above ground the home features a lightweight timber structure of UK softwood and beech glulam beams, wrapped in breathable wood-fibre insulation and finished in local Oolitic limestone and British ash.

To reduce embodied carbon and wet trades, standard concrete screeds were completely replaced with clay underfloor heating tiles, complemented by breathable clay plaster and recycled gypsum lining boards. Where foundations were structurally necessary against the sloping ground, the structure was rationalised to use less concrete and utilised lower carbon concrete.

The building is driven by passive principles, sinking its northern elevation into the hillside to minimise winter heat loss while orienting triple glazing to the east, south, and west. A 10-metre central stairwell topped by an openable rooflight acts as a passive ventilation column, cooling the interior naturally alongside extensive sedum and wildflower green roofs. The solar PV array and air source heat pump enable the home’s energy demand to substantially beat RIBA 2030 targets.

Box House

Box House is a pioneering custom self-build home which demonstrates an accessible, low-carbon entry point for first-time buyers. Built in just four weeks through our "No Building As Usual" live-build education programme, the project gave rise to the U-Build system.

The original two-bedroom dwelling achieved an exceptional embodied carbon rating of less than half the footprint of a traditional build.

The building's core relies on a high-performance, fabric-first philosophy using natural materials whilst targeting Passivhaus standards. The spruce plywood blocks are left exposed internally and filled with sheep's wool insulation to achieve Passivhaus standard insulation alongside superb airtightness. Triple glazing, a green roof, and a solar panel system further reduce the home's operational footprint. Thanks to the highly efficient thermal envelope, the house functions entirely with a very minimal heating system.

Reflecting a commitment to long-term adaptability, Box House was planned for future expansion to accommodate a growing family. In 2024, the owners collaborated with Studio Bark and student builders to create a bedroom extension. By carefully disassembling the existing roof, the team recovered the original roof insulation and U-Build blocks for use in the new construction.