Limits of raw timber design
Saving old timber
Antepavilion 2021 - The Sellout
More coming soon
Many historic buildings across London are built using timber - often with limited capacity for extension or conversion, particularly roofs and loft floors. As long as the timber is dry and sound, it can be reused and strengthened, rather than replaced.
An easy way of retaining existing floor joists that need to support higher loads (e.g. An extra storey) or span further (due to the demolition of a supporting wall) is to screw structural plywood boards into the joists to form a composite section. Care must be taken in the continuity of the boards, and often additional joists are required to ensure the strength capacity. But retaining the joists always leads to reduced material costs, increased stiffness and there are even construction benefits: laying new joists between the existing ones vs. Removing and replacing with new ones (not ignoring the programme cost of screwing the ply boards into the joists!).
Old pitch roofs are often not designed to modern standards. When alterations are made, the existing structure cannot be retained knowing that it does not meet today's structural requirements. But the timber is a valuable structural element that can be retained in place to reduce the new structure required. In a number of projects, Public House have carefully incorporated the structural capacity of the existing material into the overall capacity of new timber roof rafters and new timber ridge or propping beams. Whilst additional timber elements are almost always required, the amount of new elements is greatly reduced and can easily be incorporated into the existing structural zone.
A guiding principle of sustainable design is to always reduce the amount of new materials required in the first place, by reusing and retaining existing materials. As with most things sustainability-related - these solutions are more labour intensive and require careful design and detailing. But we also always see significant material cost savings. Below are some more examples of our old/new timber designs!