If you’re wondering whether a prefabricated steel substructure is right for your project, you’ll want to know more about the finish.

Substructures are required for many different purposes. For example, they can be used to store water, can be installed externally or internally, and maybe used in a dry or humid environment.

The good news is that there are plenty of options to suit just about any type of project!

As a subcontractor who specialises in prefabricated steel substructures, let me talk you through some of the options for materials and finishes.

What are the options for materials?

The material and finish you can choose for a prefabricated steel substructure really depends on the environment you’re going to use it in.

The main options for the material your prefabricated steel substructure can be built from are:

  • Mild steel (with or without finish – more about this below)
  • Stainless steel
  • Aluminium

Most people are a bit concerned at the idea of using mild steel in the ground, as it can corrode if it isn’t protected properly. However, we got in an expert in the field of steel corrosion, Dr. J.P. Bloomfield, to investigate and put together a report.

He was able to confirm that even up against the most acidic ground conditions (rare in the UK), the way prefabricated steel substructures are built means they’ll last over 100 years in the ground.

You can read his report right here.

One of our clients, Winvic Construction, had a project in Southampton which required four substructures built using mild steel, and one for stainless steel. This best suited the client’s requirements, and helped reduce the cost of completing them all with stainless steel.

Which finishes are available for a substructure?

If you were to opt for a prefabricated steel substructure built from mild steel, you could choose a finish as an extra barrier to help protect your substructure from corrosion.

Your main finish options are:

  • Gloss 2 pac paint
  • Matt paint
  • Galvanised
  • Rubber-based paint (commonly used for swimming pools)

The finish you select for your substructure will impact on the overall cost. For example, if you choose for your substructure to be galvanised, it will require transportation to a galvaniser’s to be dipped and then transported back to our facility for some final finishing touches.

If you choose 2 pac gloss, your substructure will remain at our facility in order to be painted, which works out as being more economical.

Advice from a specialist subcontractor

Feeling unsure of which option might suit you best? This is something that, like most companies offering something unique, we’re be happy to help guide you through – that is, if you’re lacking a definitive specification of what the finish should be.

As a rule of thumb, anything which will be external or store water, we’d specify as galvanised. However, we can also offer a possible cost saving and look at using a rubber-based swimming pool paint (as I mentioned above).

Another example would be if your substructure was to be used in a chemical environment. We would be more likely to guide you towards using stainless steel – depending on which chemicals are being used.

Whereas, if your substructure were intended to be used internally, we’d most likely suggest a 2 pac gloss finish. If this finish is maintained,regularly cleaned and not left saturated in oil or corrosive material, it can last up to 20 years.


I hope this blog has been helpful when learning of the different finishes (and materials) available for a prefabricated steel substructure.

If you do have any questions – or want to know more about what’s possible – feel free to drop us a comment, below. Or, alternatively, you can get it touch with us directly to discuss your project!