Back in May we wrote about the construction materials research we were undertaking, we were looking to find out where our steel, concrete and timber come from. Whilst we managed to find the source of our timber, the steel trail has proved to be tricky to follow….but here is what we have found out.

As you would expect construction consumes more steel than any other – in buildings alone it is 425mt globally. Steel beams, rebar, metal studs and sheet cladding all go to make up this figure. Strangely we use more steel (rebar) in concrete frames than we do in steel frames.

Steel is the world’s most recycled material with some 95% of steel recycled at end of life. However, this is not an automatic tick in the sustainability box. Over two thirds of steel is made from mined ore and less than 15% of steel comes from end of life scrap. Most of the steel made in the UK is from mined ore – probably from Brazil. We tend to make steel using blast furnaces which can only accept small amounts of scrap steel.

It is difficult to put a finger on the recycled content on the 1.5mt of steel sections we use in UK construction annually. Perhaps it might be as high as 20%? All the more reason to support companies like Portal Power, one of the few UK companies to stock second-hand steel section for re-use in new buildings.