Have you recently discovered prefabricated steel as another way to build below-ground level?

If like many of the main contractors who approach us, you’ve only ever been aware of in situ and precast concrete, you probably want to know more about prefabricated steel substructures.

You may have had some common questions, such as:

You’re probably also wondering if this method of below-ground construction can save you money. Well, like many things, the answer isn’t so straightforward.

As a subcontractor who specialises in prefabricated steel, I’m going to attempt to answer that question as best I can.

Is prefabricated steel typically more affordable?

I really wish there was an easy answer to this question. In reality, sometimes prefabricated steel substructures can work out to be more affordable than in situ or precast, whereas sometimes the opposite is true. Just like anything that’s bespoke, prices can vary depending on different scenarios, products and building sites.

So, there’s no easy answer. However, I’m going to tell you in which scenarios prefabricated steel can be the best solution in terms of cost.

However, one way to think of it is that the benefits of prefabricated steel can greatly outweigh the risks of more traditional methods, and there will be savings in terms of time spent on-site during the installation, a reduction is time spent rectifying quality defects on site after the works have been completed along with long-term maintenance costs due to water ingress issues.

TIP: To give you a better idea of cost, check out our blog: ‘How Much Does it Cost to Install a Prefabricated Steel Substructure?’.

How to save money with a prefabricated steel substructure

Money can be saved during the construction process if your below-ground activity is on the critical path. This is due to the fact that prefabricated steel typically reduces site preliminary costs. It can also reduce preliminary costs in some cases even when below-ground activity isn’t on the critical path.

For instance, if a more traditional method of building runs over programme, this could eventually start impacting on the critical path and the overall project duration.

Also, due to the steel substructure being extremely solid and robust, the tolerance of the product is extremely high. This means very limited risk of quality problems, and due to the watertight nature of the steel structure, there will be no problems with leaks.

If you’re used to working with traditional in situ or precast concrete, you’ll know how costly and time-consuming it can be to rectify defects. For instance, if your site manager’s costs are £250 per day, and your project goes over by four weeks, you can imagine how much extra that alone could cost.

That’s before even thinking about liquidated ascertained damages (LADs) if your programme runs over or the time you may have to spend on site after practical completion rectifying the defects.

Advice from a specialist subcontractor

If you think a prefabricated steel substructure could be right for your project, seek out a subcontractor who specialises in prefabricated steel. They should be able to listen to your needs and provide free, impartial advice. Ask them about what ways they’ve helped previous clients – they will probably have some client testimonials they can show you.

In terms of affordability, if you’re able to provide them with all the right information, they should be able to offer you a quote – with no exclusions or assumptions – within five to ten working days.

We recently installed a 3.5m deep, stainless steel interceptor tank for one of our repeat clients. They told us they now won’t consider constructing out of in situ concrete, due to the possible long-term problems leading to potential ongoing maintenance costs and issues for them as a company in terms of continually rectifying defects.


Thanks for reading. Hopefully this blog has managed to give you a better idea on some of the ways you could potentially save money with a prefabricated steel substructure. The biggest way is by eliminating the risk of going over-programme with your project, along with reducing the risk of quality issues and leaks/cracking that could be costly to rectify.

Do you have any specific questions about saving money with a prefabricated steel substructure? Let me know in the comments – or alternatively, get in touch with me directly. I promise to respond with something helpful.