Natural Materials for Sustainable London Homes: An Architect's Guide for Homeowners

Homeowners in urban areas like London seek ways to make their homes eco-friendly. The age and historical significance of old houses in London present challenges in making them more sustainable. There is an increasing recognition of the advantages of utilizing natural and sustainable construction materials, even with the abundance of energy-efficient modern options. Natural materials provide environmental benefits, aesthetic appeal, and durability and promote a healthier living environment.

But with so many options available, how can homeowners navigate the world of sustainable building materials?

In this guide, we will explore the various natural materials that can be used to create sustainable homes in London. From cork insulation to natural stone, these materials help reduce a home's carbon footprint and add a unique and natural aesthetic to the space. Learn how incorporating natural materials can help homeowners make their urban homes more eco-friendly and sustainable.

A Renaissance of Natural Materials in Architecture

For centuries, buildings were made using traditional construction methods, such as brick, stone, and timber.

Modern construction methods started with the technological advancements of the Industrial Revolution, which led to the widespread use of concrete, steel, glass, and petroleum-based products in buildings.

The advent of modern methods of construction has revolutionised the building industry. However, it has also inadvertently contributed to poor indoor environments. Modern building techniques often prioritise speed and cost-efficiency over the quality of materials used, compromising the health and well-being of occupants.

Using synthetic materials in modern construction has been linked to poor indoor air quality. These materials often contain volatile organic compounds (VOCs), which can be released into the air, causing respiratory problems and other health issues. Additionally, modern construction methods may not prioritise adequate ventilation and natural light, contributing to a subpar indoor environment. Renovating or retrofitting your traditional building with modern construction methods can be detrimental to your health, the health of the building and the environment.

As concerns about climate change and environmental sustainability have grown, there has been a renaissance of interest in natural construction materials. This renaissance of natural materials parallels the rise in popularity of sourdough bread over white bread. Just as sourdough bread offers a wholesome and nourishing substitute for white bread, the return to natural materials in construction promises a renewed focus on human health and well-being.

Natural materials offer a range of benefits for sustainable eco-homes in London. They are renewable, biodegradable, and have low embodied energy compared to conventional modern materials.

There is a growing recognition of the importance of returning to traditional construction materials compatible with conventional building methods. Natural materials such as wood, stone, and clay have stood the test of time and have proven to create healthier living spaces. These materials have inherent properties that regulate humidity, absorb pollutants, and promote overall well-being.

While synthetic insulation products may have higher reported performance, flexible natural insulations that adjust to older buildings can enhance performance once installed.

The Most Eco-Friendly Construction Materials For An Urban Eco-home Refurbishment

Using sustainable construction materials is essential when making your urban home more eco-friendly. As a homeowner, you can reduce your carbon footprint by choosing materials with minimal environmental impact, conserving resources, and contributing to a greener future. Natural materials offer a combination of durability, energy efficiency, and environmental sustainability, making them ideal choices for environmentally conscious homeowners. By incorporating these materials into your project, you can make steps towards a more sustainable future while enjoying the benefits of a comfortable and eco-friendly living space.

Timber

Timber is a sustainable and eco-friendly building material, making it a perfect choice for a sustainable refurbishment or retrofit.

One of the key benefits of using timber as a building material is its ability to lock in carbon. When trees are harvested to produce timber, they store carbon dioxide that has been absorbed from the atmosphere.

Additionally, using timber in construction promotes forest conservation and supports local economies by generating employment opportunities. Its lighter weight also facilitates easier transportation and construction. Moreover, timber materials have a natural aesthetic appeal and provide a comfortable and warm living environment.

What timber products are suitable for a sustainable refurbishment or extension?

 1. Timber Frame: Timber frame construction is a sustainable building method that uses wooden posts and beams to create a structural framework. It is lightweight, energy-efficient, and has a lower carbon footprint than traditional construction methods.

2. Cross-Laminated Timber (CLT): CLT is a sustainable alternative to concrete and steel for structural purposes. It consists of layers of timber boards arranged perpendicular to each other, providing strength, stability, and thermal insulation.

3. Laminated Veneer Lumber (LVL): LVL is manufactured by bonding thin layers of wood veneer. It offers excellent strength and stability, making it suitable for structural beams and columns and reducing the need for steel or concrete.

4. Glulam Beams: Glulam beams are made by gluing together layers of timber to form a solid and versatile structural element. They can replace steel or concrete in construction projects, minimising embodied energy and carbon footprint.

5. Wood Fibre Insulation: Made from recycled wood fibres, this insulation material is an eco-friendly alternative to synthetic counterparts. Wood fibre insulation contains no harmful chemicals, provides good thermal and acoustic properties, and helps reduce carbon emissions.

6. Timber Cladding: Timber cladding can improve a building's energy efficiency and aesthetic appeal. It is an additional insulation layer and can be sourced from responsibly managed forests.

7. Timber Windows and Doors: Timber windows and doors offer excellent insulation properties, reducing heat loss and energy consumption. They are also durable and can be easily repaired, contributing to a longer lifespan. 

8. Engineered Wood Flooring: Engineered wood flooring has a top layer of real wood and a base layer made from plywood. It provides the same aesthetics as solid wood flooring but requires less timber, making it a sustainable choice.

9. Plywood: Plywood is made from thin layers of wood veneer glued together, making it a versatile and sustainable product. It can be used for various applications, including wall cladding, flooring, and furniture. Plywood uses less wood than solid timber and can be made from sustainably harvested trees.

10. Furniture Grade Plywood: Similar to regular plywood, furniture grade plywood offers a higher quality finish. This product is perfect for sustainable renovation, ensuring durability, longevity, and a sophisticated appearance.

11. Recycled or Upcycled Timber: Using reclaimed or upcycled timber for renovation projects helps reduce the demand for new materials and saves trees from being cut down. It adds character and uniqueness to a renovation while minimising waste.

Utilising these timber products for refurbishment projects can contribute to creating sustainable and energy-efficient homes in London, promoting a greener built environment.

Cork

Sustainable Natural Materials
Cork render insulation - Spray or trowel applied 

Cork is a natural material made from the bark of the cork oak tree. It is a highly sustainable option for buildings due to its renewable nature. Cork has excellent thermal insulation properties, making it ideal for use in buildings to reduce energy consumption and improve energy efficiency. Its high compressibility allows it to be used in various applications, including flooring, wall insulation, and soundproofing. Cork is also water-resistant, making it suitable for moisture-prone areas such as bathrooms and kitchens. Additionally, it is non-toxic, hypoallergenic, and resistant to mould and mildew growth, making it a safe and healthy choice for eco-retrofits. Cork can also contribute to acoustic comfort by reducing noise transmission, and its natural texture and aesthetic appeal add warmth and character to any space. Cork is a versatile, sustainable, and environmentally friendly material used in various eco-retrofit applications to improve energy efficiency and indoor air quality.

 How can cork be used for a sustainable refurbishment or extension?

1. Cork Flooring: Cork flooring is an excellent choice for sustainability. Cork is obtained from the bark of cork oak trees without damaging the trees, making it a renewable resource. Cork flooring is durable and insulating and has excellent acoustic properties. It is also comfortable to walk on and resists mould, mildew, and pests.

2. Cork Wall Coverings: Cork wall coverings can improve insulation and acoustic performance. They are made from recycled cork granules, making them environmentally friendly and contributing to energy efficiency. Cork wall coverings can also serve as a decorative element, adding warmth and texture to any room.

3. Cork Insulation Boards: Cork insulation boards, made from agglomerated cork, are an eco-friendly alternative to traditional insulation materials. These boards have excellent thermal and acoustic insulation properties, reducing energy consumption and creating a more comfortable living space.

4. Cork Accessories: Several cork accessories can be incorporated into a sustainable refurbishment. Cork is commonly used for making furniture, from chairs to tables, and for decorative items such as lampshades, coasters, and bulletin boards. These environmentally friendly products add a natural and unique touch to the interior design.

Hemp

Hemp, a versatile and sustainable building material, has gained popularity in the construction industry for its numerous advantages.

Hemp has several key advantages as a sustainable building material. Firstly, it is an eco-friendly alternative to traditional materials, requiring significantly less energy than concrete or steel. Additionally, hemp can be grown quickly and requires minimal water, making it a highly renewable resource.

Hemp is lightweight, which makes it easy to transport and work with during construction. It also has excellent insulation capabilities, providing both thermal and acoustic insulation. This helps buildings utilising hemp to maintain a comfortable indoor temperature, reducing the need for excessive heating or cooling.

However, hemp's benefits as a building material extend beyond its sustainable properties. Hemp is highly breathable, allowing moisture to escape, which helps prevent issues like mould growth. It is also naturally fire-resistant, making it a safer choice for construction. Moreover, hemp is resistant to pests and insects, eliminating the need for chemical treatments.

What hemp products are suitable for an extension or refurbishment?

1. Hemp insulation: Using hemp insulation in the walls, floors, and roofs can significantly improve the house's energy efficiency. Hemp insulation is eco-friendly, prevents heat loss, and reduces carbon emissions.

2. Hempcrete: As an alternative to traditional concrete, hempcrete is a natural, lightweight, and biodegradable material made from a mixture of hemp hurd, lime, and water. Hempcrete can be used to construct walls, floors, and ceilings, enhancing thermal insulation while maintaining breathability.

3. Hemp fibreboard: Hemp fibreboard is a sustainable alternative to traditional timber-based fibreboards. It can be used for wall panels, furniture, and flooring. Hemp fibreboard is durable, moisture-resistant, and also acts as an excellent sound insulator.

4. Hemp-based paints and finishes: Opting for hemp-based paints and finishes can minimise the release of volatile organic compounds (VOCs) into the indoor air. These natural paints are non-toxic, environmentally friendly, and promote better indoor air quality.

5. Hemp fabrics and textiles: Incorporating hemp fabrics and textiles, such as curtains, upholstery, and bed linen, can enhance sustainability within the home. Hemp textiles are strong, breathable, and biodegradable, making them a greener choice than conventional textiles.

Clay

Clay is a versatile and sustainable building material that has been used for thousands of years in construction. Its uses and advantages as a sustainable building material are numerous.

Firstly, clay is readily available in most parts of the world, making it a cost-effective and accessible option for construction. It can be sourced locally, reducing transportation costs and the associated carbon emissions. Additionally, clay is abundant and renewable, as it is continuously formed through the natural erosion of rocks over time.

Furthermore, clay is an excellent insulator that helps regulate temperature and reduce energy consumption. Its thermal properties make it ideal for constructing energy-efficient buildings, as it can keep spaces cool in summer and warm in winter. Clay also has a high thermal mass, meaning it can absorb and store heat, releasing it slowly over time.

Clay is also a durable and long-lasting material, with many historic buildings made from clay still standing today. Its natural composition and resilience allow it to withstand weathering, erosion, and other environmental factors, reducing the need for frequent repairs and maintenance.

What clay products are suitable for an extension or refurbishment?

1. Clay bricks: Traditional clay bricks are made from natural materials and offer durability and insulation. They can be used to build or extend walls, ensuring a sustainable construction process.

2. Clay roof tiles: Replacing conventional roof tiles with clay ones adds a distinctive aesthetic appeal and provides natural insulation, reducing energy consumption and creating a more sustainable home.

3. Clay plaster: Ideal for giving a natural and earthy finish to interior walls, clay plaster is eco-friendly, breathable, and can regulate humidity levels, improving indoor air quality. It is an excellent alternative to synthetic materials.

4. Clay floor tiles: Clay floor tiles provide a natural and warm feel to any space. They are durable, recyclable, and have a low environmental impact.

5. Clay-based paints: With their low VOC (volatile organic compound) content, clay-based paints are a healthier and more sustainable alternative to conventional paints. They are made from natural pigments and are breathable, allowing the walls to maintain their moisture balance.

Lime

Lime is a versatile and sustainable building material that has been used for centuries. It offers several advantages over traditional construction materials, making it an attractive choice for modern eco-friendly designs.

One primary use of lime is in mortar, which is used to bind bricks or stones together in construction. Lime mortar has several advantages over cement-based mortar. Firstly, it allows buildings to breathe, as it is porous and can absorb and release moisture. This helps to prevent dampness and mould issues and enhances the overall longevity of the structure. Additionally, lime mortar is more flexible than cement mortar, allowing for movement without cracking, which is particularly beneficial in areas prone to seismic activity.

Another advantage of lime is its low carbon footprint. Producing lime requires lower energy input than cement, resulting in reduced carbon emissions. Lime can also reabsorb carbon dioxide from the atmosphere, making it a carbon-negative material. This makes it an excellent choice for environmentally conscious builders.

Lime is produced through a process called calcination, where limestone (calcium carbonate) is heated to a high temperature, resulting in the production of quicklime (calcium oxide). Quicklime is then mixed with water to produce hydrated lime (calcium hydroxide), which is the form commonly used in construction. Lime has several desirable properties, including being fire-resistant, antibacterial, and able to enhance the durability of other building materials.

What lime products are suitable for an extension or refurbishment?

1. Lime plasters: Lime plasters are breathable and allow moisture to escape, preventing dampness and maintaining a healthy indoor environment. They are an excellent alternative to cement-based plasters, which can trap moisture and lead to mould growth.

2. Lime mortars: Lime mortars are flexible and durable, making them ideal for repointing or repairing brickwork or stonework. They have superior adhesive properties and allow for movement, reducing the risk of cracking.

3. Lime renders: Lime renders provide a protective and weatherproof coating for exterior walls. They are breathable, allowing the building to regulate moisture naturally and preventing damage caused by trapped moisture.

4. Limecrete floors: Limecrete floors are made by replacing a portion of the traditional concrete mix with lime-based materials. They are breathable, which helps to control moisture levels and improve indoor air quality.

5. Lime washes: Lime washes are eco-friendly alternatives to conventional paints. They are made by diluting hydrated lime with water, providing a breathable and durable finish for internal and external walls.

Stone

Stone has been used as a building material for thousands of years due to its durability, versatility, and sustainability. One of the critical advantages of stone as a sustainable building material is its longevity. Stone structures can withstand harsh weather, erosion, and fire, ensuring a longer lifespan than other building materials. This reduces the need for frequent repairs or replacements, resulting in less waste and decreased environmental impact.

Additionally, stone is abundant in nature and requires minimal processing as a building material. This reduces energy consumption and carbon emissions associated with manufacturing processes. Stone also has excellent thermal properties, providing natural insulation that helps regulate indoor temperature and reduce the need for excessive heating or cooling. This contributes to energy efficiency and reduces the carbon footprint of buildings constructed with stone.

Stone is primarily made through natural geological processes, where rock formations are subjected to heat and pressure over millions of years. This leads to the formation of different types of stone, each with its unique properties and characteristics. Some common types of stone used in construction include granite, marble, limestone, and sandstone. These stones vary in colour, hardness, and texture, offering various design possibilities.

Natural Materials in our Upper Walthamstow Project | Natural Stone, Timber and Lime Plasters

What are the uses of stone for an extension of refurbishment?

1. Structure: Structural stone elements can be used in an extension or refurbishment project for load-bearing walls, columns and features like door and window lintels. Stone provides excellent structural stability and can support the weight of the building with minimal maintenance.

2. Cladding: Stone cladding can enhance the exterior walls of a home, providing both insulation and aesthetic appeal. It helps regulate temperature and reduces the need for additional heating or cooling.

3. Flooring: Stone flooring, such as marble, limestone, or slate, is an excellent choice for sustainable refurbishment. It is highly durable, easy to clean, and can withstand high foot traffic. Additionally, stone floors can help maintain a consistent temperature and improve indoor air quality.

4. Paving: Stone paving offers a sustainable solution for pathways, driveways, and outdoor spaces. It is resistant to weathering, requires minimal maintenance, and allows rainwater infiltration, reducing surface runoff.

5. Roofing: Natural stone roofing tiles, like slate or clay, provide excellent insulation and reduce energy consumption. They also have a long lifespan, are fire-resistant, and can enhance a property's aesthetics.

6. Countertops and surfaces: Stone, such as granite or quartz, is popular for kitchen and bathroom worktops and wall panels. It is resistant to heat, scratches, and stains, ensuring longevity and reducing the need for frequent replacements.

Other materials

This list of materials is not exhaustive. We have not mentioned some apparent materials, such as strawbale and rammed earth, mainly because they are unsuitable for London.

Also, given the urgent need to find sustainable solutions, there is a significant movement behind research into innovative materials that aim to harness traditional materials and natural systems.

Some examples include:

Sheep's Wool: Sheep's wool is an excellent insulator and can be used in walls, roofs, and floors. It is non-toxic, breathable, and has excellent moisture-wicking properties. Additionally, it is fire-resistant and can help reduce energy costs.

Ashcrete: Ashcrete is a building material made from waste ash, such as fly ash from coal power plants. It is lightweight, durable, and has excellent insulation properties. Ashcrete can be used for walls, floors, and foundations, reducing your home's carbon footprint.

Ferrock: Ferrock is an innovative material made from industrial steel dust and a combination of recycled materials like ash and slag. It is stronger than traditional concrete and has a much lower carbon footprint. Ferrock can be used for various applications, including walls and flooring.

Plant-Based Polyurethane Rigid Foam: This foam is made from renewable plant sources, such as soybeans, and is an excellent alternative to traditional insulation materials. It is lightweight, fire-resistant, and offers superior thermal insulation.

Enviroboard: Enviroboard is a sustainable alternative to MDF and particleboard. It is made from recycled wood fibres and non-toxic bonding agents. Enviroboard can be used for cabinets, shelves, and furniture, offering a durable and eco-friendly solution.

Bamboo: Bamboo is a fast-growing grass that is both strong and sustainable. It can be used for flooring, cabinets, and furniture. Bamboo is highly renewable and has a low environmental impact.

Mycelium: Mycelium is the vegetative part of a fungus and can be used to create eco-friendly insulation and building materials. It is a lightweight, fire-resistant, and renewable material that decomposes naturally at the end of its lifecycle.

Timbercrete: Timbercrete is a composite material made from sawdust, clay, and cement. It has excellent insulation properties and is highly durable. Timbercrete can be used for walls, floors, and even structural elements.

Newspaperwood: Newspaperwood is a material made from recycled newspapers. It is created by compressing layers of newspapers into log-like blocks that can be used for furniture, flooring, and wall paneling. Newspaperwood offers a unique aesthetic while giving new life to old newspapers.

Compressed Paper (Richlite): Compressed paper, also known as Richlite, is a dense and durable material made from recycled paper and other fibres. It is fire-resistant, waterproof, and can be used for countertops, flooring, and exterior cladding.

Denim: Denim insulation is made from recycled denim fibre and is an eco-friendly alternative to fibreglass insulation. It is non-toxic, fire-resistant, and offers excellent thermal and sound insulation properties.

Chalkbarn: Chalkbarn is a natural material made from chalk and agricultural waste such as straw. It can be used for insulation, plaster, and as a building material. Chalkbarn is breathable, non-toxic, and offers good thermal performance. 

These materials offer potential solutions to reduce environmental impact and improve the sustainability of construction practices.

However, finding the balance between innovation and feasibility is critical for homeowners. While exploring new materials and techniques is essential, ensuring these solutions are viable and can be implemented on a larger scale is equally important. By finding this balance, the construction industry can significantly progress towards creating a more sustainable built environment.

Summary

Choosing natural materials for your home can bring numerous benefits. First, natural materials are environmentally friendly and sustainable, reducing your home's carbon footprint and helping preserve the planet for future generations. As a homeowner, you can also benefit from a healthier indoor environment, as these materials naturally regulate humidity levels and do not emit harmful chemicals.

Additionally, natural materials often offer superior insulation properties, effectively reducing energy consumption and saving you money on heating and cooling costs in the long run. These materials also have a longer lifespan than synthetic counterparts, meaning less maintenance and replacement costs over time.

Furthermore, natural materials bring a unique and aesthetic appeal to homes. Whether it is the warmth and authenticity of wood, the elegance and durability of stone, or the versatility and beauty of plants and flowers, incorporating natural elements into your home design creates a visually pleasing and welcoming atmosphere.

Overall, natural materials give homeowners a holistic approach to building or renovating their homes. From the environmental benefits to improved indoor air quality and cost savings, choosing natural materials is a smart and sustainable choice that enhances the comfort and enjoyment of one's home.

Next Steps

Ciarcelluti Mathers Architecture has a wealth of experience incorporating natural materials into our projects. Our innovative approach has resulted in stunning designs seamlessly blending with the surrounding environment. Whether using timber, stone, hemp, or cork, our team at Ciarcelluti Mathers Architecture understands how to harness the potential of these materials to create extraordinary spaces.

If you have a project in mind that involves natural materials and seek expert advice, we encourage you to contact us. Our team will be delighted to discuss your ideas and help bring them to life, ensuring a harmonious blend of nature and design.