Can You Build a Single Storey Extension From Timber?

This question often arises among homeowners seeking to expand their living space while maintaining a balance between cost-effectiveness, sustainability, and aesthetics. Timber frame construction presents a compelling solution, offering a versatile and efficient method for extending homes. In this article, we’ll explore the feasibility and benefits of constructing a single-storey extension using timber, shedding light on the process from inception to completion.

The concept of building a single-storey extension from timber shares parallels with constructing a garden room, but it’s attached to your house. Both endeavours involve integrating additional living space seamlessly into the existing structure.

So in short, yes, it’s entirely possible to build a single-storey extension using timber frame construction. Timber frame construction offers several advantages for single-storey extensions, including speed of construction, sustainability, and design flexibility.

I’ll answer a few questions commonly asked in regards to this topic but before I do, let’s take a look at the process. Please remember the detail in this article only discusses single storey extensions. If you are looking to build double storey extensions, seek professional advice, as there are far more building regulations and planning applications that need to be taken into consideration.

Brief Overview of the Build Process

1. Design: Work with an architect or designer experienced in timber frame construction to create a design that meets your needs and complies with local building regulations.
2. Planning Permission: Check with your local planning authority to determine if planning permission is required for your proposed extension. In some cases, single-storey extensions may be permitted development, but it’s essential to confirm this before proceeding.
3. Foundation: Prepare the foundation according to the specifications provided by a structural engineer. Timber frame extensions typically require a concrete slab or strip foundation to support the structure.
4. Timber Frame Construction: Once the foundation is in place, the timber frame can be constructed on-site. This involves assembling timber studs, joists, and rafters to form the framework of the extension. The frame is typically built using prefabricated timber panels, which are then erected and fixed in place.
5. Cladding and Roofing: Once the frame is in place, external cladding and roofing materials can be installed. These can include a variety of options such as timber cladding, brick slips, render, or metal cladding, depending on your design preferences and planning requirements.
6. Interior Finishes: After the exterior is completed, the interior of the extension can be finished to your specifications. This may include insulation, plasterboard, flooring, and any fixtures or fittings required.
7. Services Installation: Plumbing, electrical, and HVAC services can be installed within the timber frame structure as needed.
8. Finishing Touches: Complete the extension with any finishing touches, such as painting, landscaping, or installing windows and doors.

If you’re considering your own timber framed extension then you should consider these vital questions that will help determine if this is the right option for you.

Do I need foundations for a timber frame single storey extension?

Yes, you will need foundations for a timber frame single-storey extension. While timber frame construction is lighter than traditional brick or blockwork, it still requires a solid foundation to support the structure and distribute its weight evenly.

The type of foundation required will depend on various factors, including the size and weight of the extension, the soil conditions on your property, and local building regulations. However, common foundation types for timber frame extensions include:

1. Concrete Slab Foundation: This is a popular choice for single-storey extensions. It involves pouring a thick layer of concrete directly onto a prepared sub-base, providing a stable and level platform for the timber frame structure.
2. Strip Foundations: These are continuous concrete footings that run along the perimeter of the extension’s walls. Strip foundations are typically used when the ground conditions require additional support or when the extension spans a large area.
3. Pad Foundations: These are isolated concrete pads placed at specific points under load-bearing elements of the timber frame structure, such as posts or columns. Pad foundations are suitable for smaller extensions or where ground conditions are less favorable.

Regardless of the type of foundation used, it’s essential to consult with a structural engineer or building professional to determine the most appropriate solution for your specific project. They will assess factors such as soil stability, load-bearing requirements, and local building codes to ensure that the foundation meets safety and structural integrity standards.

Are timber frame extensions Mortgageable?

Timber frame extensions are mortgageable if certified by an engineer and compliant with building regulations. Lenders typically assess their value relative to the property and prefer standard construction. If the existing structure is of standard build and the extension is certified, most lenders will consider it. Ensuring adequate insurance coverage, providing documentation of certification, and working with a knowledgeable mortgage broker can facilitate the process. With these measures, homeowners can increase the likelihood of securing mortgage financing for their timber frame extensions.

Do I need building regs for a timber frame extension?

Yes, you will generally need to comply with building regulations when constructing a timber frame extension. Building regulations are legal requirements set by government authorities to ensure that buildings are constructed to a minimum standard of safety, accessibility, and energy efficiency.

For timber frame extensions, building regulations will typically cover various aspects of the construction process, including:

1. Structural Integrity: Building regulations will require the timber frame structure to be designed and constructed to withstand the expected loads and forces, ensuring it is structurally sound and stable.
2. Fire Safety: Regulations will specify requirements for fire resistance and protection measures, particularly important when using timber as a construction material. This may include fire-resistant cladding or treatments for timber elements to enhance fire resistance.
3. Thermal Performance: Building regulations aim to promote energy efficiency and reduce carbon emissions. Therefore, they may require the timber frame extension to meet certain standards for insulation, air tightness, and thermal performance to minimise heat loss and energy consumption.
4. Ventilation and Air Quality: Regulations may specify requirements for ventilation to ensure adequate air circulation and maintain indoor air quality within the extension.
5. Accessibility: Building regulations may include provisions for accessibility, ensuring that the extension is designed to accommodate individuals with disabilities or mobility impairments.
6. Drainage and Plumbing: Regulations will cover aspects such as drainage systems, plumbing installations, and waterproofing measures to prevent water ingress and ensure proper functioning of utilities within the extension.

It’s essential to consult with your local building control authority or a qualified building professional early in the planning process to understand the specific building regulations that apply to your timber frame extension project. Compliance with building regulations not only ensures the safety and durability of the extension but also helps avoid potential issues during construction and future property transactions.

What are the pros and cons to a timber framed extension?

Pros of Timber Frame Extensions

1. Cost-Effective: Timber frame construction often requires less labor and time, making it a more economical option compared to brick-built extensions.
2. Quicker Construction: Timber frame extensions can be erected faster than brick-built counterparts, reducing on-site labor costs and minimising disruption to homeowners.
3. Sustainable: Timber is a renewable resource, making timber frame extensions environmentally friendly compared to brick-built extensions, which often require more energy-intensive manufacturing processes.
4. Design Flexibility: Timber frame construction offers greater design flexibility, allowing for more intricate architectural designs and customisation options.
5. Energy Efficiency: Timber frame structures can achieve high levels of insulation, contributing to improved energy efficiency and reduced heating and cooling costs.

Cons of Timber Frame Extensions

1. Perceived Durability: Some may perceive timber frame constructions as less durable than brick-built structures, although proper maintenance can mitigate this concern.
2. Fire Risk: Timber is combustible, posing a potential fire risk. However, fire-resistant treatments and building regulations can address this issue effectively.
3. Moisture Sensitivity: Timber can be susceptible to moisture damage if not adequately protected, requiring proper waterproofing measures during construction.
4. Limited Load-Bearing Capacity: Timber frame structures may have limitations in supporting heavy loads compared to brick-built constructions, requiring careful engineering and design considerations for large-scale extensions.
5. Maintenance Requirements: Timber frame extensions may require more frequent maintenance compared to brick-built counterparts, such as periodic checks for rot or insect damage and recoating with protective finishes.

Pros of Brick Built Extensions

1. Perceived Durability: Brick-built extensions are often perceived as more durable and long-lasting than timber frame constructions, providing a sense of solidity and permanence.
2. Fire Resistance: Brick offers excellent fire resistance compared to timber, enhancing safety in the event of a fire.
3. Low Maintenance: Brick-built structures typically require minimal maintenance over their lifespan, reducing long-term upkeep costs for homeowners.
4. Sound Insulation: Brick provides better sound insulation properties compared to timber, offering a quieter living environment.
5. Resale Value: Brick-built extensions may command higher resale values due to their perceived durability and traditional aesthetic appeal.

Cons of Brick Built Extensions

1. Higher Cost: Brick-built extensions often require more labor and time to construct, resulting in higher overall costs compared to timber frame constructions.
2. Slower Construction: The construction process for brick-built extensions can be slower compared to timber frame constructions, leading to longer project timelines and potential delays.
3. Limited Design Flexibility: Brick-built extensions may have limitations in design flexibility compared to timber frame constructions, as bricklaying techniques may restrict architectural options.
4. Environmental Impact: Brick production has a significant environmental impact due to energy-intensive manufacturing processes and resource extraction.
5. Difficulty in Retrofitting: Retrofitting brick-built extensions or making structural modifications can be more challenging and costly compared to timber frame constructions, requiring specialised skills and equipment.

Conclusion

If you’re reading this article because you wish to tackle this job yourself, there might be an easier option. A timber framed garden room can be built to the same standards as a dwelling extension but without all the difficult planning and building regulation applications. It’s possible to extend your living space without the hassle. You can find out how I created extra living space for under £6,000 in my article here.

While building a timber frame extension offers many advantages, it’s crucial to adhere to building regulations to ensure safety, structural integrity, and compliance with legal requirements. By working closely with qualified professionals, obtaining necessary certifications, and securing approvals from local authorities, you can embark on timber frame extension projects with confidence. With careful planning and attention to detail, timber frame extensions can not only enhance living space but also add value and sustainability to homes for years to come.