Steel as a circular material

Why it is a special material here

Steel can be remelted without loss of properties: the recycled material makes steel of the same quality as primary steel. With many other building materials recycling means downgrading — concrete ends up as rubble in a lower-value use.

On top of that, collecting steel works economically: scrap metal has a market, so recycling is not dependent on subsidy.

A demountable structure

An LGS frame is typically screwed, not welded. At end of life this gives two options:

• Dismantling: some members come out intact and can in principle be reused.
• Selective demolition: steel separates easily from the other materials, which improves recycling efficiency.

Compared with monolithic structures this is a real difference.

What should not be overstated

Demolition is still work

Demountability is an opportunity, not an automatic outcome. If the structure is built with bonded, foamed, hard-to-separate layers, selective demolition gets harder.

Material quantity is not everything

Environmental performance is not one number: production energy, transport, the sum of materials built in and the operation of the building all count. Steel’s advantage is in recyclability, not in every indicator. EPD and life cycle assessment.

The data is always product-specific

Actual environmental data comes from a product-level environmental declaration, not from generalities.

What design can add

• Less material: an optimised, not over-sized structure means directly less material.
• Separability: a build-up whose materials can be separated at demolition.
• Documentation: if a record of what was built in survives, demolition can be planned.
• Long life: the best environmental decision is not having to replace the structure.

The point

Steel’s circularity advantage is real but not automatic: demountability has to be designed, and less material built in is always worth more than better recyclability.