Timber Frame Extensions: What You Need to Know - Powerpillar

Timber Frame Extensions: What You Need to Know

by | Jul 8, 2022 | House Extension | 0 comments

Timber Frame Extensions: What You Need to Know

You’re probably expecting a lot of mess and disruption, even if you’ve never built a timber frame extension.
It’s likely that you’re now considering a timber frame for your next extension because of your experience or if you’re a professional builder.
Almost any type of home in the London can be extended with a timber frame. It can be used for single-story ground floor timber extensions and a two-story or wraparound extension off-site. We have gathered all the information you may need for timber frame extension.

What Is A Timber Frame?

All vertical and horizontal loads are carried to the foundation by a wooden frame in modern stud timber. Most timber frames are hidden in voids between external bricks and plasterboard and unseen. It has no difference in appearance from an extension constructed from bricks and blocks.
Exceptions to this rule include post-and-beam timber frames in which some structural elements, like roof trusses and rafters, are left exposed. Alternatively, timber frame panels can be mixed with post and beam structural frames.

Why Do You Need Timber Frame Extensions

Timber frame extension London provides more space and added value in addition to providing extra space.
In contrast with traditional timber extensions that typically take weeks to weatherproof, timber frames can be weathertight in days, reducing construction time and the impact of bad weather.
Timber frame extensions are suitable for sustainable projects and provide good airtightness and thermal performance.

Types Of Timber Frame Construction

Closed-panel systems

It is sometimes possible to install the services, channels, and ducts before installing the panels – this is similar to an open-panel system.
Some manufacturers deliver panels with fully glazed external joinery, but doors and windows are typically not installed when the boards are provided.

Open-panel systems

The external sheeting is fixed to the sides during the installation of the softwood frames. In contrast, the interior face of the structures is left open, allowing the electrical and plumbing services to be run and the insulation to be installed later. Once this has been achieved, a plasterboard is attached to close up the frame on the inside of the frame.

Benefits of Installing Timber Extension


Traditionally, the use of timber frames in construction has been regarded as a low-quality construction method due to their lightweight properties. People prefer bricks, blocks, and steel because they feel more solid than bricks, partnerships, and steel construction. Although timber frame is not just exceptionally strong and durable, it can endure the harshest weather conditions for decades. A timber frame building is one of our oldest and most durable buildings. In the same way, that brick and block walls comply with Building Regulations; timber frame structures must also meet fire protection requirements.
In addition to being relatively lightweight, timber also has the advantage of being reasonably cheap and easy to transport. The lightweight nature of the foundations might also save the ground owner money on the cost of digging foundations.

Design flexibility

The timber frame construction method is very flexible in constructing a house. Design possibilities are endless, and there are no limitations to what can be done. With vaulted ceilings and beams exposed, large, open plans can be built. Incorporating structural steelwork into the construction of an extension and leaving it exposed can give it a more contemporary look and make it look more elegant.


Timber is an ideal building material for eco-friendliness and renewable resources. If one is removed, trees can be replanted in their place after they have been felled. Sustainable forestry will, however, only allow this to happen if the timber is sourced responsibly. It shows that the wood is replaced after harvesting and that no harm is done to the ecosystems in the vicinity and the environment as a whole. As a result of their reliance on finite raw materials, bricks and concrete are less environmentally friendly than timber. It takes less energy and creates less pollution when the timber is converted into a building material that can be used as opposed to aluminium, steel, concrete, and brick.

Timber Frame Extension Cost

You will have to consider the size of your planned room when determining the price of a timber frame extension. Depending on the design, size, and type of materials used, the project’s cost will be based on an estimation per m2 of the plan. For planning and construction, timber frame building firms usually provide quotes on a per m2 basis ranging from £1,400 to £2,400. However, the overall cost of wood can reach as high as $2,400 if you choose to use expensive materials such as oak wood. Additionally, your total budget should also consider factors like the extension’s complexity and the finishing required for the extension.

Single-storey timber frame extension cost

In the case of a four-metre by five-metre timber frame extension with a single storey, £28,880 is the average cost for the project. New homes are commonly built on timber frames because they save time in site management, resulting in a faster sale and quicker completion. A factory environment can be better controlled when it comes to quality control than a construction site, so timber frames do not have a huge financial advantage. This is the most important advantage in terms of the timeframes for completing the extension.

Two-storey timber frame extension cost

If both storeys have the same size, a good rule of thumb is to add 50% extra to the average cost of £28,880 for a single storey. In the case of a two-storey timber frame extension, a total cost of £43,320 would result from using this timber frame extension cost calculator to calculate the cost of such an extension.

Planning Permission For Timber-Framed Extensions

It should be noted that the use of timber as a construction material does not affect the need for permission to build with it in itself. To ensure that oak-framed buildings are constructed according to the law, all timber used in their construction shall be able to support loads and be fire-resistant.
The main factors considered when granting planning permission are the dimensions, the use and the location. Therefore the material itself is usually not a factor to consider. This is not the case, however, for one reason.
Unless a conservatory is built, materials used on the exterior should match the existing house’s appearance.

Building Regulation Approval

You will need timber frame extension regulations. However, there are exceptions to the general rule regarding building regulations approval for timber frame extension. If your intended floor space is between 15 square meters and 30 square meters, you may be exempt from the requirement for building regulations approval. It is important to note that even if you do not need planning permission for a timber frame extension, you will still need to apply for building regulations.

Is a timber frame extension built on-site?

Timber frame extensions are constructed with timber frames, meaning they are not manufactured in factories but made on-site by professional joiners power pillars. As part of the design of the timber frame, a structural engineer would specify what type and size of timbers are required for the structure, lintel cripples, and other structural elements, along with a schedule of nailing.
Since the timbers are loose when delivered, you can easily transport them to where your panels will be erected, thanks to their ease of carrying.
A joiner will assemble the timber frame panels on-site according to the structural engineer’s specifications. It will be possible to measure the existing structure by this point to manufacture appropriate timber panels.
A structural engineer will have advised you on this aspect during the planning process if the design includes large expanses of glazing. A section of this can be manufactured off-site, delivered separately, and then bolted together on-site during construction.

The timber frame extension London cannot be used for any part of the extension that is below ground level. In this case, it is possible to combine the timber frame with another method of the extension building.

Timber Frame Extensions and Movement Gaps

The movement gap must be formed between any extension and the existing building to accommodate shrinkage and thermal and moisture movement.
There will most likely be a difference in construction between the extension and the existing building, so the expansion/contraction of the extension will differ. Therefore, a movement joint is necessary.
Stainless steel channel ties are used for movement joints to provide lateral restraint while allowing vertical and horizontal movement. A flexible sealant is used to seal the gap between the two structures.

Emmanuel Nwaebo

Emmanuel Nwaebo is the Managing Director at Powerpillar Ltd and has more than 25 years experience in building construction and renovations. He has a bachelor’s in Electronics and Electrical Engineering with certification in Construction Health and Safety Technician (CHST). With an experience in managing construction and renovation services for years, he is extremely passionate about property management and loves helping people find their dream property.

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