Are you curious about how long a prefabricated steel substructure will last for in the ground once it’s been installed?

When many first-time clients find out that prefabricated steel substructures are constructed with mild steel, they think: “But won’t it corrode and leak?”

You may also be worried about the quality of the weld, or of the opinion that nothing is ever 100% watertight – so that sooner or later, it’ll fail.

However, as a subcontractor who specialises in prefabricated steel, let me tell you how prefabricated steel is different – and how long you can actually expect a prefabricated steel substructure to last in the ground.

How long will a prefabricated steel substructure last for?

Of course, this is a vital question to ask. We wanted firm proof, so that we could provide you with a solid answer to this question.

That’s why we got a specialist in the field of steel corrosion, Dr. J.P. Bloomfield, to investigate. He put together a report which confirmed the way prefabricated steel substructures are built means they’ll last over 100 years in the ground, up against the most acidic ground conditions (which are rare in the UK).

He said in his report:

“In a worst case scenario where aggressive soil/water reaches the tank wall, it is a 6 mm steel sheet. Eurocode 3 states that for steel piles in aggressive soil for a 100 year life the maximum corrosion rate is 0.06 mm/year/side. It will therefore take 100 years for the corrosion to penetrate a 6 mm steel tank wall.

As it will take several decades for the contaminants to reach the tank steel surface before corrosion can initiate, we can confidently expect a 100 year design life from Premier Cellar Company.”

So, you can be fairly certain that if you choose this method, your substructure won’t leak or corrode. This equates to the same as a guarantee.

As for the welding process, prefabricated steel substructures are manufactured off-site in a facility that’s CE certified to confirm that the welding process is code two. This should be monitored and regulated to ensure a consistent high quality every time.

How does prefabricated steel compare to precast and in situ concrete?

The warranty that most precast companies issue will vary (so it might be worth asking different companies). However, typically in situ concrete should be able to last at 10 to 30 years in the ground, if the specification is Hanson or Sika etc

With precast concrete, it’s a little different, and its longevity will really come down to the type of concrete that has been specified, along with the membranes and product they use to place between the joints. For instance, Sika’s concrete system comes with a 15-year warranty.

Prefabricated steel forms a complete barrier, and won’t crack like concrete does. For example, if after 30 years and one day (or 15 years and one day for Sika), water starts to penetrate your Hanson Gold concrete substructure, then certain areas of your substructure will need to be repaired.

With prefabricated steel, you’ll know that the barrier will always be there, keeping your substructure intact. And if there’s a low water table with less acidic ground, it may possibly last double the time an expert has place on the product.

Advice from a specialist subcontractor

Want to know whether a prefabricated steel substructure might be a good solution for upcoming projects? Especially if you’re feeling skeptical, I’d recommend visiting a previous site that’s installed prefabricated steel, or visit a factory to see how they’re built.

You can also check out online reviews, testimonials and case studies online. Like the one we did that involved us installing a substructure that was 75m long x 4m wide x 1.5/2m deep for the place the London Taxi Company build their cars.

It speaks volumes about what can be achieved with prefabricated steel!


I hope this blog has helped give you a better understanding of how long prefabricated steel substructures will last for in the ground. If you opt for this method, it’s a fair bet that you can expect your substructures to last for over 100 years. In fact, we have some clients who won’t go back to in situ or precast, haven’t tried our approach!

TIP: Take a look at some of the other benefits of prefabricated steel, via our recent blog.

Do you have any specific questions about using prefabricated steel for your project? Let me know in the comments. I’m always happy to help!