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Unlocking the True Cost of Timber Frame Extension in 2024

image of an expensive modern timber frame extension

Picture this: a classy, sustainable, and cost-effective extension to your home. Sounds enticing, right? This is what a timber frame extension offers. But just how much does the cost of timber frame extension amount to? Let’s unravel this together.

Key Takeaways

  • The cost per square meter for a timber frame extension in the UK ranges from £1,400 to £2,400, potentially rising for premium materials like oak and factoring in additional expenses for groundwork, landscaping, and finishing.
  • Timber frame extension costs are influenced by design complexity, material choices, location, and regional factors, with considerations for energy efficiency, durability, planning permissions, and building regulations.
  • Financial planning involves estimating budgets accounting for design, materials, and labour
  • , with options for financing such as loans or savings; off-site construction offers benefits of efficiency, quality control, and waste reduction.

Exploring Timber Frame Extension Costs

A timber frame extension under construction with workers assembling the frame

Grasping the costs involved in timber frame extensions is vital. This includes understanding the price per square meter, unforeseen expenses, and the cost difference between oak and standard timber frames.

Price Per Square Meter

The cost per square meter of a timber frame extension typically ranges between £1,400 and £2,400 in the UK. However, these costs can fluctuate based on factors such as the size, materials, and location.

For instance, opting for premium materials like oak can significantly increase the cost per square meter due to their superior quality and longevity.

Hidden Extras and Additional Costs

Formulating a budget for a timber frame extension requires consideration of unforeseen and additional costs. These can include:

  • Groundwork and drainage costs, which are typically excluded from the initial quote and can range from £1,400 to £2,400 per square meter
  • Landscaping, budgeting approximately £25-£30 per m2 for hard landscaping and £40-£50 per m2 for concrete paving slabs wet bedded in cement
  • Finishing works such as plastering, painting, and decorating, which often entail additional costs not included in the initial quote

It’s important to factor in these costs to ensure an accurate budget for your timber frame extension.

Comparing Oak Frame vs Standard Timber Frame Costs

Comparison of oak frame and standard timber frame extensions with cost analysis

If deciding between oak frame and standard timber frame extensions, bear in mind that oak frames usually command a higher price, starting at around £2,400 per sqm. This cost difference can be attributed to factors such as the finish, size, and complexity of the extension, the quality of materials used, and the weight of the structure.

The Factors That Affect Timber Frame Extension Pricing

There are several factors that can affect the cost of a timber frame extension. These include the complexity of the design, the choice of materials, and the location of the extension.

Here’s a detailed examination of these factors.

Design Complexity and Custom Features

A timber frame extension can vary in cost depending on its design and features. Here are some factors that can impact the cost:

  • The size and complexity of the design
  • Required lintels for timber frame
  • Custom features, such as intricate designs and flexible design possibilities
  • The use of tailored finishes and select materials to enhance property value

A simple, rectangular design will generally be less expensive than a complex design with custom features. It’s important to consider these factors when planning your timber frame extension.

These factors can significantly contribute to the financial investment required for a custom timber frame extension.

Material Choices and Availability

The choice of materials can also greatly impact the cost of your timber frame extension. Softwoods such as pine, fir, and spruce are frequently used in timber frame extensions, and while these woods are generally less expensive than premium woods like oak, they can still elevate the cost per square meter due to their superior quality and longevity.

Also, the availability and cost of different woods can be affected by sustainability considerations, logging regulations, and geographical factors.

Location and Access

The location of your timber frame extension can also affect its cost. Regional factors such as the cost of living in the area and local building codes can influence building costs, with costs typically being higher in larger cities. Additionally, site access can impact labour demands and transportation expenses, particularly in remote areas.

Hence, these location-specific challenges should be factored into your budgeting process.

Financial Planning for Your Timber Frame Extension

Having examined the factors that can impact the cost of a timber frame extension, we will now discuss financial planning strategies. This involves estimating your total budget and exploring suitable financing options.

Estimating Your Total Budget

Work the manufacturer of the timber frame to estimate the total budget for your timber frame extension, consider the following factors:

  • Design and planning: Typically accounts for 20-25% of the total budget.
  • Materials: Costs will vary depending on the type and quality of materials chosen.
  • Labour: Generally calculated on a per m2 basis and factored into the average cost per square meter of the extension. This typically amounts to around £1,800 per m2.

By considering these factors, you can get a better idea of the overall budget for your timber frame extension.

Financing Options and Savings

Various financing options could be considered for funding your timber frame extension, depending on your financial situation. These include obtaining a mortgage from a specialist lender or exploring specific construction loans. Additionally, the government provides support through various initiatives such as the Timber in Construction Innovation Fund, aimed at promoting the use of sustainable wood in construction.

You could also consider using your personal savings to finance the project, as timber frame extensions are often cost-effective due to the use of affordable materials and the shortened construction time resulting from the pre-fabrication of components in a timber frame kit.

Timber Frame Extension: Construction Costs Breakdown

Construction cost breakdown of a timber frame extension including foundation and structural elements

Here’s a detailed analysis of the construction costs related to timber frame extensions. This includes the costs for foundation and groundwork, structural elements, and finishing touches.

Foundation and Groundwork Expenses

The foundation and groundwork are integral parts of your timber frame extension and can significantly impact the overall timber frame extension cost. They typically range between £1,400-£2,400 per square metre. The cost can fluctuate based on factors such as the scale of the project, the complexity of the site, and the soil conditions.

Structural Elements and Labour Charges

The structural elements of your timber frame extension are another key cost factor. These include:

  • Roof joists
  • Load bearing wall panels, structural wall panels, and timber frame panels
  • Vertical studs
  • Horizontal rails

The cost of these elements can vary due to factors such as materials, labour, design complexity, and location.

Labour costs, for example, typically range between £1,400-£2,400 per m2.

Finishing Touches and External Cladding

Lastly, finishing touches, such as external cladding and interior decoration, can add to the overall cost of the extension. There are various options for external cladding that are appropriate for timber frame extensions, including timber, brick, stone, render, vertical tiling, flint, metal, porcelain tile, brick slips, aluminium cladding, composite cladding, perforated cladding, uPVC cladding, and zinc cladding. The cost of these finishing touches can vary based on the finish of the extension, the size and complexity of the extension, the quality of materials utilized, the type of frame, the quantity and type of insulation, the thickness of the frame, and the utilization of prefabrication.

The Long-Term Value of Timber Frame Extensions

Energy-efficient features of a timber frame extension with emphasis on thermal performance

Beyond the initial costs, it’s also important to consider the long-term value of timber frame extensions. This includes their energy efficiency, durability, and sustainability.

Energy Efficiency and Thermal Performance

One of the key benefits of timber frame extensions is their excellent thermal performance and energy efficiency. Here are some advantages:

  • Timber frame extensions have insulation properties that help maintain favourable indoor temperatures.
  • They demonstrate excellent thermal and acoustic efficiency.
  • This contributes to a lower environmental impact.
  • It improves indoor comfort levels by maintaining consistent temperatures through energy-efficient design.

Durability and Maintenance

Timber frame construction, particularly in the form of timber frame extensions, offers several benefits of a timber frame structure. One unique aspect is the timer frame extension, which can provide additional functionality to the overall design. Some of these benefits include:

  • Energy efficiency
  • Durability
  • Minimal maintenance
  • Resistance to rot
  • Aesthetic and functional advantages

It’s recommended to undergo scheduled maintenance at specific intervals to ensure the extension remains in optimal condition.

Navigating Planning Permission and Regulations

Next, we will outline how to navigate planning permission and building regulations for timber frame extensions. This is an important step in the process of building your extension, as non-compliance can result in fines and legal issues.

Criteria for Planning Permission

Planning permission may be required depending on the size, appearance, and location of the extension. For example, if the extension does not infringe upon boundary lines or create access issues to nearby roads or footpaths, planning permission may not be necessary.

However, if the extension exceeds the criteria established by local council regulations, an application for planning permission becomes mandatory.

Building Regulations to Consider

When it comes to building regulations for timber frame extensions, it’s important to adhere to the following fire protection regulations:

  • Utilize treated timbers
  • Install fire-resistant linings for walls and floors
  • Integrate a cavity barrier between the internal timber structure and the external cladding material

Additionally, the insulation of a timber frame extension must adhere to the current building regulations.

Maximizing the Benefits of Off-Site Construction

Finally, we’ll explore the benefits of off-site construction for timber frame extensions, a method that offers speed, efficiency, and quality control.

Speed and Efficiency on Site

Off-site construction allows for speedy assembly and reduced on-site disruption. In fact, a typical house shell can be erected in under five days. This method provides efficiency benefits including:

  • High standards of thermal insulation and air tightness
  • Improved energy efficiency
  • Shortened construction timescales
  • Decreased heating and cooling expenses

Quality Control and Waste Reduction

Factory-built timber frame extensions offer the following benefits:

  • Improved quality control
  • Waste reduction
  • Construction in accordance with NHBC Standards, guaranteeing rigorous technical requirements and performance standards
  • Minimization of waste through the utilization of prefabrication techniques
  • Use of timber, which is biodegradable and recyclable

Real-Life Cost Examples of Timber Frame Extensions

For a clearer understanding, we will examine some real-life cost examples of timber frame extensions. For instance, a small 15m² extension can cost between £30,000 to £42,000, while opting for premium materials like oak can increase costs to over £2,400 per square meter. These examples illustrate the significant variations in the cost of timber frame extensions, which can be attributed to factors such as the finish of the extension, its size and complexity, the quality of materials used, the frame’s thickness, structural requirements, as well as the type and size of the timber frame used.


In conclusion, timber frame extensions offer a stylish and sustainable solution for expanding your living space. While the initial costs can vary significantly, their long-term benefits such as energy efficiency, durability, and minimal maintenance make them a worthwhile investment. Additionally, off-site construction offers speed, efficiency, and quality control, making the construction process smoother and more cost-effective. So, with careful planning and good financial management, a timber frame extension can add significant value to your home.

Frequently Asked Questions

Is a timber frame extension cheaper to build?

Yes, timber frame extensions are typically cheaper to build than traditionally built ones due to reduced labour hours.

Do I need foundations for a timber framed extension?

Yes, the current foundations of the building should be sufficient to support the timber framed extension, especially if they were designed to support concrete or brick. Using hardwood timber such as Oak should not significantly change the foundation requirements.

What are the disadvantages of timber frame extension?

The main disadvantage of timber frame extensions is the risk of rot, especially if they are poorly built or in a very wet climate. However, if properly constructed and maintained, the risk of rot can be minimal.

How much does a 25m2 extension cost?

The average cost for a 25m2 extension is approximately £25,000 to £50,000.

What is the typical cost per square meter for a timber frame extension?

In the UK, the typical cost per square meter for a timber frame extension ranges from £1,400 to £2,400.

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