Reuse of steel in construction means taking steel components from an old building and using them in a new project with minimal re-processing. Thus, structural components such as beams, columns or non structural components such as cladding panels or staircases are taken from one project and used in another. This can also include the reuse and adaptation of whole steel frames in situ.

Reuse is most easily achieved for engineered components, which can be readily disassembled.

Steel reuse hierarchy

The following is an interpretation of the waste management hierarchy as it applies to steel:

1. Reuse whole buildings as existing.
2. Strip back and reuse the structure of an existing building on the same site.
3. Dismantle an existing structure and reuse the complete structure on a new site.
4. Reuse individual components such as beams, columns, cladding, and stairs from deconstructed buildings in new buildings with minimal reworking.
5. Reuse individual components such as beams, columns, cladding, and stairs from deconstructed buildings in new buildings with significant reworking.
6. Send steel to mills for recycling.

Benefits of steel reuse

It is generally thought that the environmental benefits from reuse are greater than recycling since reuse requires little reprocessing. Reuse also preserves the value added when manufacturing the component and generally minimises any environmental impacts from reprocessing. Whole buildings or individual components can be reused. For steel this is confirmed by a study in the UK by the Steel Construction Institute which suggests that reusing steel leads to significantly greater environmental benefits than steel recycling and correlates well with savings in greenhouse gas emissions.

Thus, from an environmental, and often economic, point of view it is desirable that as many components of a building as possible are extracted from the waste stream for reuse at the end of their useful life.

Process issues

Increasingly, designers are looking for opportunities to use steel components from demolition of existing buildings in their new designs. Reuse of steel components requires designers and contractors to be more flexible in approach. Salvaged components may not be readily available off the shelf, and may be difficult to source. One of the principal problems with reuse is to co-ordinate demand with supply, and this can affect the whole design and construction process – reclaimed materials do not show up at the right time, in the right amount or the right dimension.

With a traditional approach to design, the steel components are specified and sized to suite the spanning requirements of the architect’s proposals. This is not a problem if new steel components are to be used, off the shelf. However, reused components do not generally come “off the shelf”, rather they are identified on demolition sites by salvage contractors. Thus, when proceeding to construction the required size of salvaged steel may not be readily available. This may necessitate redesign to suite available salvaged components or choosing whichever oversized components are readily available.

To maximise the potential for reuse, the starting point for the new design may in the future be an inventory of the available materials from salvage.


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