Earth Day 2024 – Eliminating Plastics from Construction
On this Earth Day, we are looking at how we can eliminate plastics from our construction.
Plastics were the wonder material of the 20th century. They have so many applications but in recent decades concern has been building about the problems they cause, particularly when they reach their end of life. The promise of endless recyclability seems still to be a distant dream. This is particularly a problem with single use disposable items but is also a real problem with construction waste.
One of our more enlightened clients recently challenged us to remove as much plastic as reasonably possible from their proposed building. Traditional construction obviously didn’t contain any plastics, but it was also poorly insulated and required constantly burning fires to keep it warm and dry. Modern construction, on the other hand, has become highly reliant on plastic based insulation, membranes, etc. In this proposed detail, the main superstructure is a timber frame insulated with 300mm of wood fibre insulation behind timber cladding. Below DPC level Foamglas will be used. This material is made largely of recycled glass, is totally inert, and ultimately will break down into the sand it was made of. It has good insulating properties and also has good compressive strength allowing it to be used beneath the walls to stop cold bridging. It is, however, expensive and has a fairly high embodied carbon so we are limiting it to localised details. The floor slab will be insulated with Rockwool beneath a screed heated by an air source heat pump.
The one element of plastic remaining in this detail is the DPM. It would be easy to eliminate that by raising the floor and having a suspended timber floor, but in this instance we need to keep the floor level right down at ground level so I think we will have to accept that small compromise.
One thing we need to develop further in the future is how to remove more concrete from the substructure. Suspended floors? Stone? Limecrete?
How are you eliminating plastic from your work?
Neil McAllister
Associate Director & Project Architect
