Building fabric

The term 'building fabric' refers to structural materials, cladding, insulation, finishes, etc., that enclose the interior of a building, separating the internal from the external.

Very broadly, for most buildings, the building fabric will include a number of elements:

• The roof.
• External walls.
• Windows.
• Doors.
• The lowest floor.

Each of these will in turn be assemblies of a number of components.

The building fabric serves to:

• Protect the building occupants from the weather, such as wind, rain, solar radiation, snow, and so on.
• Regulate the indoor environment in terms of temperature, humidity, moisture, and so on.
• Provide privacy for occupants.
• Prevent the transmission of noise.
• Provide security for occupants and the building contents.
• Provide safety, for example preventing the spread of fire or smoke.
• Provide views into and out of the building.
• Provide access between the inside and the outside of the building.

It is also generally a major part of the structure of the building.

As a result, building fabric is now seen much less as just a stylistic add on to a building, but more as a fundamental part of to the way the building operates. Increasingly, this is resulting in the creation of complex, multi layered elements to the building fabric, and the use of modern materials such as high performance glazing, architectural fabrics, active shading, and so on.

The building fabric will usually contain openings as a means of providing physical access, admitting daylight, providing natural or mechanical ventilation, supplying services, allowing drainage, and so on. In some cases, this may conflict with other performance requirements, for example, openings may cause security, privacy or noise nuisance issues. These potential conflicts require careful consideration and design, which may include the use of screens, shades, baffles, and so on.

Junctions between the elements that make up the building fabric can also cause problems, for example creating a cold bridge between the inside and the outside.

Other considerations that might affect the design of the building fabric might include:

• Legislative requirements.
• Performance requirements.
• Site topography.
• Site conditions, such as noise nuisance and air quality.
• Climatic conditions.
• Shading requirements.
• Building type.
• Building services strategies, such as lighting and ventilating strategies.
• Context and stylistic considerations.
• The availability of materials and skills.
• The sustainability of materials.
• Maintenance and cleaning.
• Other requirements, such as the photovoltaics, rainwater run off or storage, landscaping, and so on.
• Durability, flexibility and expected life.
• Deconstructability and recyclability.

Good design can allow for reductions in heating and cooling loads, lower energy use and lower carbon emissions. This can mean there is a trade off between the capital cost of the building fabric, the capital cost of building services, and the operating cost of the building.

It can be more challenging to improve the performance of existing buildings. However, retrofitting can include improvements to air tightness, the introduction of double glazing, the installation of cavity wall insulation or internal or external solid wall insulation, and so on.

NB Conservation Principles, Guidance for the sustainable management of the historic environment in Northern Ireland, published by the Historic Environment Division in July 2021, defines fabric as: ‘The material substance of which places are formed, including geology, archaeological deposits, structures and buildings, construction materials, decorative details and finishes and planted or managed flora.’

Assessing risks in insulation retrofits using hygrothermal software tools, Heat and moisture transport in internally insulated stone walls, by Joseph Little, Calina Ferraro and Beñat Arregi, published by Historic Environment Scotland in 2015, defines building fabric as: ‘The sum of the structural, fixed materials of which the building is made. This contrasts with furnishings which are loose.’

[edit] Related articles on Designing Buildings

• Airtight.
• Building regulations.
• Cavity wall insulation.
• Cladding.
• Conduction.
• Convection.
• Curtain wall systems.
• Curved glass.
• Damp in buildings.
• Fabric first investigation into net zero for existing buildings.
• Façade.
• Glazing.
• Infill panel walls.
• Insulation.
• Insulation for ground floors.
• Kinetic facade.
• Load-bearing wall.
• Louvre specifications.
• Metal profile cladding.
• Passive building design.
• Sandwich panel.
• Solar gain.
• Thatch roofing.
• The building as climate modifier.
• Thermal bridge.
• Thermal imaging of the building fabric in the net zero world.
• Upcycling buildings.
• U value.
• Wall types.
• Weathertight.
• What are walls made of?

[edit] External references

• New-learn - Building fabric

Comments

Building fabric refers to the physical elements that make up the external envelope of a building. It includes the materials and components that form the structure, walls, roof, and floor, providing a barrier between the interior and the external environment. The building fabric plays a crucial role in maintaining the comfort, energy efficiency, and overall performance of the building. Here are the main components of a building fabric:

1. Walls: The walls form the vertical enclosure of a building and can be made of various materials, including bricks, concrete, stone, wood, or metal. The choice of wall materials impacts the building's insulation, thermal mass, and structural integrity.

2. Roof: The roof is the uppermost part of the building, protecting it from rain, snow, and other environmental elements. Roofing materials can vary widely, such as asphalt shingles, metal sheets, concrete tiles, or thatch. The roof's design and insulation are essential factors for maintaining indoor comfort and energy efficiency.

3. Floor: The floor is the surface that separates the building's interior from the ground. It can be constructed with materials like concrete, wood, tiles, or stone. Proper insulation and flooring materials are vital for maintaining a comfortable interior temperature and preventing heat loss.

4. Windows and Doors: Windows and doors are openings in the building fabric that allow light, ventilation, and access. The choice of window and door materials, glazing type, and design impact energy efficiency, daylighting, and indoor air quality.

5. Insulation: Insulation is a critical component of the building fabric that helps regulate the internal temperature and reduces heat loss or gain. Common insulation materials include fiberglass, cellulose, foam, and mineral wool.

6. Damp Proof Course (DPC): DPC is a barrier installed horizontally in walls to prevent moisture rising from the ground and causing dampness in the building.

7. Vapor Barrier: Vapor barriers are used to control the movement of moisture through the building fabric, helping to prevent condensation and mold growth.

8. Air and Water Barrier: Air and water barriers are used to seal gaps and joints in the building fabric, preventing air infiltration and water leakage.

9. Cladding: Cladding refers to the external finish or protective layer applied to the building walls. It can be made from materials like brick, stucco, metal panels, or composite materials.

10. Flashings: Flashings are used to prevent water penetration at vulnerable points, such as junctions between the roof and walls or around windows and doors.

Creating an efficient building fabric is essential for achieving sustainable, comfortable, and energy-efficient buildings. The proper selection and installation of materials and components help ensure a durable and well-insulated envelope that contributes to the overall performance and longevity of the building.