A lightweight, reusable formwork and building system has been developed in Australia for on-site production of robust and environmentally advantageous concrete housing.
The system developed by Australian company, Formwork Creation, is an evolution of a concept that won the 2005 Australian Engineering Excellence Award, and is designed to resist damage during extreme climatic events. The formwork and building system offers a viable option for the production of thermally efficient and highly practical dwellings that resist damage and can provide shelter during bushfires, cyclones and other natural disasters.
The formwork and building system has been refined to incorporate concrete slab roofs to permit the on-site production of entire modern concrete houses, suitable for both remote sites and urban developments.
The patented light weight reusable formwork and building system brings to small-scale concrete structures the benefits on in-situ construction that have been used for large-scale structures for 100 years.
The patented technology and equipment has no supply problems. It is easy for most semi-skilled tradespeople to use the technology and to manufacture the formwork equipment during shortages or when additional equipment is required. There are only 12 clearly identifiable components, with a maximum weight of up to 18kg for the heaviest component.
The formwork and building system advances the process further by solving the problems of construction times and the availability of low-cost formwork equipment capable of holding liquid concrete in place (while it is setting) to produce residential concrete walls and concrete roof slabs. Existing concrete standards provide all details for the concrete mix and structural engineering.
The reusable formwork and concrete building system permits the construction of complete concrete homes with variable wall thicknesses and slab roofs integrated into the structure.
The wall structure is engineered to provide optimal thermal mass insulation and environmental sustainability at competitive costs in remote or urban settings. Polystyrene wall insulation is moulded to the internal face of the external concrete walls to protect the inside of the home from the effects of outside temperature changes.
The system’s concrete roof slab, supported by load bearing in-situ concrete walls, is stronger and less complicated. The slabs are designed not to pond water and are treated with an additive to permanently seal the concrete against the penetration of water and other liquids from any direction.
The concrete structure of a standard residence (single story) with a concrete roof slab meets Australian concrete construction code requirements without variations or upgrades. Two story structures are easily accommodated with minor upgrades.
Concrete and reinforcing steel are less complicated structural building materials for housing than combinations of steel, timber, bricks and roof trusses. Yet foundations, floor slab designs, fit-out products and fit-out materials are the same for concrete homes as most other homes built on a concrete slab.
A standard 25MPa concrete mix with 7/10mm aggregate is used for the walls, beams and columns that are poured in one continuous concrete pour. A super plasticising additive is placed in the concrete mix on site to bring the liquid concrete to an easy flowing self levelling mix of about 260mm slump without effecting the finished strength of the concrete. Standard 20MPa concrete is used for the foundations, and 32MPa for the roof.
Following are the benefits of low maintenance concrete houses built using the formwork Creation system:
- Non-combustible exterior.
- Non-combustible interior structural elements.
- Fire-resistant roofs.
- Retention of structural strength under heat.
- Ability to build in water tanks for protection and insulation gains
- Reduction of the spread of room-to-room fires by the internal concrete walls.
- No joints to allow flame penetration.
- Thermal efficiency – the insulated thermal mass of the concrete structure stores and releases heating and cooling.
- Ability to support residential green roofs for comfort and ecological gains.
- Resistance to water loads and to condensation.
- No buoyancy loads and does not create flood debris.
- Resistance to structural damage, including during earthquakes, cyclones and high winds
- Non susceptibility to fungal or insect attack, including termites.
- Standard concrete roof construction provides roof top garden space to reduce the environmental impact caused by buildings.
- Environmental advantages.