Design Solution · Structural Systems
Design Solution · Dream about it
Reuse foundations and steel, then build extra floors on top.
Existing foundations and a large share of the steel frame are kept and reused, with three new office floors built on top of the retained structure. Avoiding a new substructure and frame removes most of the embodied carbon of a rebuild while increasing lettable area. The method makes intensification of existing stock viable.
Retaining an existing substructure and frame while adding floors on top compresses the embodied-carbon case for retrofit into a single measurable action: if the foundations and primary steel are already in place, the marginal carbon of adding lettable area is a fraction of a full rebuild. The strategy is credible in principle and has been demonstrated on commercial retrofits, though this record is claimed without provided evidence of structural validation methodology, load-margin calculations or carbon quantification. The engineering question that must be answered first — and can only be answered by a structural survey of the actual building — is whether the original foundations and frame carry adequate reserve capacity to accept additional storeys under current loading codes, taking account of any corrosion, connection degradation or capacity upgrades since original construction. That assessment is neither cheap nor quick, and it may return an answer that limits the number of additional floors to less than the commercial model requires. For buildings where the structural reserve is confirmed, the approach is one of the strongest tools for urban densification with low incremental carbon; the risk is committing to a retention-led scheme before the survey is complete.
#structural reuse #embodied carbon #densification