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Structural Calculations, Building Regulations and Our Detail of Build for an Oak Frame Building

Our customers ask lots of questions during the process of creating an Oak frame building and it is something we encourage. The more technical questions may involve planning permission, permitted development rights and then structural calculations plus building regulations. These may not be the most exciting parts of the project but they are very important.

Below we will attempt to explain a little about structural calculations and building regulations for Oak frame designs.

What are Structural Calculations:-

Firstly it is important to mention that for Oak frames and the construction of Oak structures structural calculations are a very niche, specialised subject.

In summary, structural calculations are a mathematically calculated design proof and summary performed using engineering principles, mathematical formulas, and specialized software. They analyse the materials used, foundation strength, joints, fixings, section sizes and load distribution relating to elements like beams and Oak posts. The calculations determine the appropriate size and materials for structural elements and ensure that the structure can withstand the loads and forces it may encounter. Structural calculations are essential to ensure the safety and stability of a building.

A structural engineers calculation is important, as providing the building and all parts of the construction are built to the engineered design, then it is indemnified against the engineers insurance company. The structural calculations report is a fundamental part of a building regulations application.


Cheshire Oak Structures Services

We have structural calculations for several building designs, mainly based on our standard garage designs with adaptions for different styles of Oak building. These take into account the type of raft base that we usually build, the size and detail of all other items involved, be it Oak frame sections, supporting Oak posts, rafter & ridge-board timbers, stud walls, screws and nails that are used.


Should your project be outside of our standard Oak frame buildings specification, then a structural engineering calculation will be needed for the specific size and make up of your building. We offer this service by way of a qualified structural engineer, who importantly is used to working with “green oak frame structures” as this is a specialist area within the construction world.  


There's no point having structural calculations if the construction and building of the Oak structure doesn't follow the details and process in the report. Below are a couple of examples from the structural engineering calculations and how they work in our designs.

The photos show the concrete raft base and dwarf brick walls we install to support our Oak buildings. The calculations are not shown as they are the exclusive property of Cheshire Oak Structures.

As part of the design and construction of an Oak frame building wind bracing is used on the stud walls between the Oak frame sections which support the Larch weatherboard and also as part of the ridge board and rafter structure. Wind bracing supports and strengthens the Oak building to withstand the forces of weather. The calculations for the wind bracing are a small part of the 53 page document which is the structural calculations report.

The examples below show buildings, by other builders, which are possibly built without structural calculations and demonstrate the problems that may then occur.

In the photo below it appears that non-structural grade Oak has been used, the huge knot in the centre has opened up and warped, causing the roof rafters to drop and the tiles to crack as a result. The Oak is of small sections and therefore, does not give the strength required to support the weight of the roof.

The knee braces, in the photo above, do not appear to have oak draw pegs holding the mortice & tenon joints together, this suggests that there may possibly not be any mortice & tenon joints. The combination of the mortice and tenon joints with draw pegs is important to stop the movement of the frame from left to right. The diagonal wind bracing (as shown on the front stud panel) should be fitted diagonally across several sections of the stud frame, not just two.

The two bay Oak carport , in the photo below, certainly does not look like it was built by an Oak frame company working to structural calculations. The roof ridge-board and rafters appear to have failed as the weight of the slate is warping the roof timbers and no doubt cracking the slates. The Oak knee braces also look as if they are not jointed, as there are no draw pegs and they have been screwed on to the main frame, this would not give the horizontal stability that they should be designed for.

Oak carport with specification & structural problems

As mentioned earlier in this blog structural calculations form part of the application for Building Regulations but, what are Building Regulations?

Building Regulations are developed by the Government and approved by Parliament. They are minimum standards for design, construction and alterations to nearly every building.

They also contain a list of requirements that ensure minimum standards for health, safety, convenience, energy efficiency, welfare and sustainability. These are referred to as Schedule 1 and they also aim to prevent misuse, abuse or contamination of water supplies. These regulations cover all aspects of construction including foundations, stability, damp-proofing, insulation, heating, ventilation, fire protection, means of escape and making sure there are adequate facilities for people with disabilities. Building Regulations consist of Parts A – P and are regularly updated.

Basically, if your building is of a certain size, usually over 30 square metres internal footprint, and depending on its location to a boundary, building regulations sign-off is required by form of a certificate. This certificate proves that the building was built to the current regulations and that it has been checked throughout the build process to ensure that all is correct.

At Cheshire Oak Structures we use a detailed build specification that is based on the structural calculations to make your Oak frame building as sound as possible when it comes to stopping water ingress, wind resistance, insect infestation, while achieving a general quality aesthetic appeal.

This is an example of an Oak two bay garage built, we assume, to a build specification which does not include the necessary detail from a structural calculations report

Two bay garage with build detail itemised

The Oak two bay garage below was designed and built by the team at Cheshire Oak Structures to the structural calculation requirements, which "tick all the boxes" to pass for a Building Regulations Certificate. Along with a few techniques and finishing touches we use, this type of detail is what makes Cheshire Oak Structures different to most other Oak frame companies.

Build specification for building regulations
Cheshire Oak Structures two bay garage

We will never be the cheapest Oak frame company out there, however, we are confident that we are designing, supplying and building a first class product.

quote relating to quality of goods
One of our favourite quotes

To talk to us about Oak frame designs, whether it be an Oak garage, Oak carport, Oak summerhouse or another Oak structure design and the full turnkey build service we offer please get in touch by using the enquiry form, calling the office on 01829 250919 or by emailing


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