When designing a shed the engineering varies according to regional wind speed and use of the building. The other areas that affect the engineering are changing a sheds span, bay size and wall height affects the required engineering. As these change in size, so does the engineered material requirements, therefore the size and thickness of structural materials. The change from one thickness or size of a structural member to another is referred to as a step or engineering step.
For.example, the size of the Cee section columns and rafters maybe 150mm with a 1.2mm thickness for a shed. Increase the size of a sheds span and wall height and that takes the materials up to the next step and the thickness might increase to 1.5mm or the perhaps c200 might be required.
When getting your quotes for your building it is a good idea to enquire about the engineering steps and what effects the size of building you are requesting has upon component sizes and thicknesses as a change in height or span of a few millimetres can save you several hundred dollars or even thousands on a large project.
This also is why you can find price differences in some sheds where the engineers of one brand will only sign off on certain standards where other engineers are prepared to sign off on a little lesser in material strength for the same job. Whilst it is not always the case, often, when you are paying a little extra for what appears to be the same size building, what you are paying for is an extra grade of engineering in the form of additional material or connections in the engineering. Generally speaking…. you do get, what you pay for.