A steel frame will be the underlying structure of your DPL building, whether that’s for:
Of course, you don’t need to take on board the technical considerations – our team do all that for you as we plan, design and install your building. However, if you’d like to delve deeper into the technicalities, here are six facts behind the frames.
1. What is a steel framed building?
These days, it’s the term often used to describe what is actually a ‘portal framed’ building. A portal frame structure is one that has a column at each side with rafters making the roof section. In the UK, most of these are built from steel frames (although concrete and laminated timber can also be used). That’s why most people now tend to refer to them as ‘steel framed’ or ‘steel frame’ buildings.
2. Why did steel take over as the main material?
It’s primarily because steel is very durable and strong, so it will last for a long time.
A ‘primary’ steel is used for the column and for the rafter making the roof section. A more lightweight ‘secondary’ steel is used to form the roof purlins, which are the horizontal cross sections that make up the majority of the roof structure and link to the rafters. The cladding is then fixed to these and to the side rail.
3. What are the main design considerations with it?
The designer needs to make sure they’re specifying the correct size and thickness for the span, for the type and weight of the roof sheets and for the use of the building. They also take account of snow loadings and any design loadings such as solar panels or heating/ventilation pipes.
There are different classes of steel framed building, depending on how many people will be occupying it or its purpose. An agricultural building will also be designed differently to an industrial one. For example, if it’s being used for grain storage, the walls will need to be strengthened enough to withstand the weight of the grain against them.
4. Taking the strain
Steel framed buildings are quite simple structures in essence. However, this brings other issues. For example, it’s important to make sure that key joint areas are designed correctly, because of the stresses and strains they can be under.
The main joint stress points are the haunch area – where the column connects to the rafter in the eaves – and also the apex. These both have a very important role to play in the strength of the building and making sure the structure is sound. They therefore need extra bracing pieces – pieces of webbing steel put into the columns to stop them twisting under the strain. Unfortunately, it is on these joint areas that companies can sometimes take short cuts to make them more cheaply.
5. Look out for the CE Mark
The CE Mark is your guarantee that a building conforms to a certain recognised standard. Structural frame manufacturers have been obliged by law to have their Design Protocol and Factory Production Control Procedures assessed to European Standard EN 1090 since July 2014. There’s an initial assessment, and if the frame maker passes, they’ll be accredited to CE Mark for their frames. At DPL, we use only quality British manufacturers and suppliers, and all our buildings carry the CE mark.
6. Up on the roof
There are also decisions to be made about the spaces between the purlins used on the roof – so they’re correct for the type of materials used. If we recommend a fibre cement roof, the purlin spaces need to be closer than with a composite insulated panel or a single skin steel roof because of the heavier weight of the fibre cement itself and also because the product is more fragile, meaning it needs more support.
Want to talk technical?
There are other aspects we also take into account when we’re looking at the best building for your needs. Our technical team love to talk steel buildings. So if you have any questions about the technical aspects of steel framed buildings, please do get in touch.