Wall construction may be revolutionised throughout Australia with the recent addition of permanent formwork, or stay-in-place (SIP) formwork to Green Star’s Responsible Building Materials credit, in acknowledgment of the increased uptake in this building system throughout the country’s construction industry.
Cement has held pride of place for decades as most popular wall construction material in Australia. One of the appeals of cement is its high compression strength.
Cement is poured into a temporary formwork to support the building material as it forms shape, strength and sets. Once ready, the temporary formwork is detached.
Other popular materials include plywood, timber and at times steel.
Cement temporary formwork may have high compression strength, but it also has weak tensile strength requiring rebar reinforcement.
If exposed to prolonged pressure traditional cement formwork has the potential to crack.
Water penetration (amongst other factors) may cause concrete cancer, which is at “epidemic” levels through-out Australia according to Strata Community Australia.
It is also labour intensive and costly, eating up as much as 40% to 60% of the entire concrete structure cost for a business.
The formwork of permanent systems can be pre-fabricated by any number of different materials including fibre, or glass reinforced plastic, thermoplastics (polystyrene, PVC), metals or cement. Unlike temporary systems, this permanent formwork will remain in place once building is complete.
Permanent system components are designed for interconnectedness, so formwork can be built with excellent efficiency.
At the moment, forward thinking Australian construction businesses are creating modular SIP systems complete with propriety components so different permanent formwork brands are produced with their own, exclusive connecting systems and moulds.
Traditional load-bearing pre-cast concrete walls and masonry block, or tilt-up walls are increasingly being replaced by these new permanent systems, used today for construction of blade columns, basements, lift shafts, stairs, retaining walls (and other areas), irrigation tanks and buildings up to 30 stories high.
The need to lower the major costs of formwork construction across the globe has driven the world-wide building sector to innovate and develop new systems and technologies over the previous 10 years or longer, and Australia has been helping lead the charge, establishing world-class material formulations, as well as patents.