Do I need Structural Calculations?

Do I Need Structural Calculations?

If you are thinking of carrying out alterations to your property you may want to read this article, which explains when and why you may need to instruct a structural engineer to carry out calculations and design for your project.

Many alterations carried out around your property will not require the assistance of a structural engineer as long as they don’t include altering any of the building that forms part of the supporting structure or load-bearing wall.

“Removing that wall without proper support in place, or without having the correct calculations and design carried out by a structural engineer (to compensate for the absent wall) could be disastrous.”

What are supporting structures and load-bearing walls?

A load-bearing wall is typically a solid-built wall that helps support the main structure of the building, keeping it from collapsing. It is an integral element in safely supporting the design and structure of the property. Supporting structures within a property could include any of the following,

  • The roof
  • Load-bearing walls
  • Foundation
  • Trusses or beams
  • Supporting walls
  • Retaining walls
  • Concrete lintels
  • PSCL (Pre-Stressed Concrete Lintels)
  • RSJ (Rolled Steel Joist)

As an example, if you intend to open up your living area and knock a wall out between a dining room/kitchen and a living room to create an open-plan style living area, it is likely that wall may form part of the supporting structure for the whole property. Not only would the wall above it be supported on that wall but also the floor and possibly the roof.

Removing that wall without proper support in place, or without having the correct calculations and design carried out by a structural engineer (to compensate for the absent wall) could be disastrous.


If this is the case, and the wall is load-bearing (supporting wall), you will need to get it assessed by a structural engineer, who will provide a report for you that will satisfy building control if you decide to knock it down. If the engineer identifies that the wall is load-bearing and you wish to remove it, you will need structural calculations for a supporting beam.

The calculations are a set of mathematical workings that demonstrate the correct loads to ensure the beam is strong enough.

Do I need a Structural Engineer for a Loft Conversion?

You will almost certainly need a structural engineer to assist with the calculations and design of the structural components. Building a loft conversion can add significant weight to the property, therefore, it is imperative the correct support is provided.

I am building a small extension, will I need Structural Calculations?

Much like the loft conversion, it is most likely you will need a structural engineer to design and calculate the beams that will be needed to support the loads of the extension. In many cases also, a structural engineer will design and calculate the correct foundation needed. The process of ensuring you have the correct calculations will satisfy building control.


Can I do my own Structural Calculations?

To satisfy building control, it is strongly advised to use a professional structural engineer for calculating the structural loads, unless you have undertaken professional training yourself.

What if I let my builder use his experience to work out the right beam needed?

It is not advisable to rely entirely on the advice of the builder to determine what support beam your project needs. Needless to say, building control will want to see that the beam has been calculated and designed by a professionally trained, qualified and competent person.

It is strongly advised to seek the professional help of a structural engineer, which, will save you time and money in the future, especially if you wish to sell the property and there is no record of the beam being calculated by an engineer.

Building Surveys
It could cost you more in the long run if you don’t use a reputable structural engineer

What is included with Structural Calculations

If professionally carried out, a structural engineer’s calculations and design will include all the specifications for the structurally supporting beams within the project. It will also include a design to assist builders understand the installation and connection of the beams. A full list of calculations like this, will be supplied to allow the builder to hand over to the fabricators to have manufactured exactly to spec.


Our best advice is to have your alterations carried out properly and professionally, which will save you time and money in the long term.  By ensuring you have used a structural engineer to calculate and design your support beams, it also provides peace of mind for you and your family.


One thought on “Do I need Structural Calculations?

  1. Jane Brightley says:

    We had a builder knock down a wall in our house. He assured us it was safe and it was not a supporting wall. When we asked Alpine Surveys to do a survey we were horrified by the report. The wall was a supporting wall for the floor above and without their assistance could have had a disaster on our hands. Luckily we have now resolved the issue.

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