Frequently asked questions

What are concrete blocks?

Frequently asked questions

What are stacked concrete blocks and what are they used for? Our structural engineers have collected some of the most frequently asked questions about using stacked concrete blocks and have tried to answer them as clearly as possible.

1. What are concrete blocks?

Concrete blocks are large lego blocks made of concrete that are meant to be stacked. The concrete used for these blocks often comes from surpluses from construction projects: so-called residual concrete.

This residual concrete is cast in moulds, resulting in concrete blocks that boast all the benefits mentioned in question 2.

2. What are the advantages of concrete blocks?

Concrete blocks are a very easy, versatile building material. Thanks to the special lugs at the top and the recesses at the bottom, they're easy to stack without shifting.

As a result, you'll have a reusable, durable and sustainable stacked wall that's cheaper than cast walls.

3. What are concrete blocks used for?

Concrete blocks are very versatile and can be used for many different applications, including trench silos and earthen pits for the agricultural sector, trench silos for the civil engineering sector, retaining walls, structural walls for factories/roofs and road barriers.

4. Why do I need an analysis?

To make sure that your wall made of stacked blocks of concrete is sufficiently stable, you need to have it analysed. Stacked concrete block walls are unreinforced walls, which means that they have a specific and abrupt yield point, rather than a yield range. As a result, such a wall can collapse 'spontaneously' when the structure is overfilled, for instance. Tilt resistance is the most important criterion.

With an analysis, you can assure clients, inspection authorities and users that the stacked walls used in a particular structure are entirely safe.

5. Can I do this analysis myself?

There are lots of factors to consider when analysing the stability of a wall made of concrete blocks, including wind, subsurface, bulk type, wall dimensions and, possibly, additional stresses.

It takes a trained structural engineer to properly assess all these different factors properly. Our structural engineers will provide you with a structural analysis report that you can submit to the building authorities.

6. The maximum fill height of my structure is less than expected. How come?

In accordance with the Eurocodes, we are bound to observe a minimum safety level of 2.1, which generally means reducing the maximum fill height by 25%.

This choice was made because of the additional risks involved in using retaining walls instead of regular structures, based on the subsurface type, the stress types and the fact that these walls are made of stacked blocks.

7. What about earthquake resistance?

In seismic zones, the substructure on which a concrete wall has been built may be unstable, which has a negative impact on its stability. The stability of a stacked wall depends largely on the subsurface.

At Concrete Block Engineers, we can also assess the stability of structures located in seismic zones.

8. Are you an independent consultancy firm?

Concrete Block Engineers is a completely independent consultancy firm, which means we can analyse all different types of concrete block walls and structures for commercial and non-commercial customers in the Netherlands and abroad.

9. I can't find my question. Who can I contact?

Can't find an answer to your question? Please feel free to contact us by calling +31 (0)182 231400 EN/NL or sending an e-mail to

  • Expert and independent constructive advice
  • Available in Dutch, English,German, French and Spanish
  • Suitable for submission to the Building Control Department
  • Tailored structural advice for your situation
  • Pricing starts at € 400 for a basic calculation, exclusive of VAT.
  • Stability calculation in your mailbox