Why is it convertible?
The Convertible Home is highly adaptable. The frame is lightweight, it can be picked up and moved and can be easily adapted for a variety of both permanent and non-permanent structures. All internal walls are non-load bearing allowing for greater flexibility.
With fast construction, semi-prefabrication allowing to the millimetre precision and overall cost effectiveness the Convertible House is an attractive housing solution that won’t drain your hip pocket.
The Convertible Home prototype is off-grid producing its own energy and heating, harvests rain water and treats grey and black water on site. Not only that, we consider how clients will live in the house and interact with the environment around them. The structure is lightweight both in its design and impact on the environment, we like it ‘lightly touching the landscape’.
The Convertible House is the perfect weekender or holiday retreat with rural and coastal dwellings in mind. The construction is low cost, secure, storm and fire resistant. The simple semi-prefabricated components reduce reliance on skilled contractors. The lightweight frame offers sensitivity to the environment and the building can be locked down increasing general security and protection from nature’s elements while you are away.
The innovative design and lightweight construction makes the Convertible House an ideal solution for commercial applications such as multiple dwellings for holiday park developments, mining, communal and retirement villages.
The structure could also be used where emergency shelter is required and for remote and environmentally sensitive areas such as National Parks. The building can be easily relocated or dismantled and re-erected as required. It has excellent fire resistant construction which is also ideal for wild fire prone zones.
The lightweight frame provides an excellent support for either lightweight permanent cladding, or high tensile fabric coverings. The structure can be easily adapted for a variety of both permanent and non-permanent structures.
The design principle of the Convertible Building provides flexibility and the basic construction system is relatively simple to erect and extend. Design features include:
- Strong, light and readily available materials (sourced locally where possible) or alternatively able to be cost effectively freighted are considered a critical component of the design.
- The modular nature of the construction, using primarily lightweight materials, assists in simplifying sourcing and delivery of materials.
- The “meccano” type assembly process allows for the construction of the outer superstructure quickly, therefore the execution of the internal construction and fit out is relatively unaffected by adverse weather conditions.
- One of the main features of the Convertible Building is the unique, lightweight and versatile modular portal frame design and connection details which simplify and speed up the erection process.
- The open web framing allows for services to be safely and easily routed during construction or retrospectively. If required strategically located removable panels can be fitted so that the roof/external wall cavity can be easily accessed.
The building materials specified have been carefully considered and selected using the following criteria:
- Inherent durability
- Potential for recycling
- Embodied energy
- Ease of transportation (ideally locally produced and sourced)
- Overall cost effectiveness
As an example, steel Colourbond CGI (corrugated iron) roof and wall cladding has been specified for its inherent properties, i.e. durability, low thermal mass, low maintenance, fire and storm resistance and economics. It’s also ideal for rain harvesting and provides an appropriate architectural response for both rural and coastal locations.
Plywood was the world’s first engineered timber product and has been predominantly specified for the ceiling and wall linings while also assisting with bracing the structure. The specified plywood is produced from 100% renewable and sustainable plantation resource timber, is economical and has an environmentally friendly manufacturing process using 100% resource landscaping materials (bark and log cores). Other inherent qualities including low toxicity, low embodied energy, low thermal mass, high uniform strength and low shrinkage, versatility, lightweight and impact resistance make it an appropriate choice.
The main superstructure has been designed using lightweight steel framing. Although steel has relatively high embodied energy compared to timber, unlike timber it’s infinitely recyclable. Steel has been selected for its superior strength to weight properties, durability, stability and versatility. All of the framing components can be pre-cut and/or pre-fabricated to the required shape and lengths thereby eliminating the need for additional cutting on site and wastage. Most of the members can be quickly and easily assembled using self taping screws or bolted connections.
Internal walls are non-load bearing and can therefore be constructed using a variety of lightweight materials e.g. timber or steel stud framing. The prototype dwelling’s internal walls have been made from a combination of compressed rice and / or wheat straw (renewable raw materials) rigid infill panels which are easily cut and shaped and plaster lined timber stud framing.
The house has been orientated to maximise its exposure to northern solar access. High performance windows and sliding doors have been positioned in all north facing habitable rooms providing excellent natural light. The radiant heat energy entering through these windows in the colder months is absorbed by the thermal mass of the compressed cement sheet floors and in combination with the floor and wall insulation, this heat is stored and re-radiated into the building.
The solar conservatory over the stairwell /entry area acts as a heat bank (solar collector) during the day in winter by maximising solar gain. This warm air is trapped, filtered and redistributed to other rooms using heat recovery ventilation.
The combined free and environmentally friendly passive heating from the solar collector, radiant heat and thermal mass reduce the sole reliance on the solid fuel heater to heat the home.
In summer, this optional solar conservatory / collector over the stairwell acts as a thermal chimney drawing in cooler air from lower level operable screened vents and expelling it through the heat recovery ventilation system and static ridge vents located at both ends of the building. This thermo suction effect is also employed in other areas of the house to assist with cooling and ventilation. Operable roof ventilators can be additionally located along the ridge line to expel warm stale air in the warmer months. Good cross flow ventilation is achieved in the main living areas by using openable south facing roof windows and this can be further enhanced by locating openable smaller south facing roof windows in the utility areas.
Once the external superstructure is completed, it also acts as a thermal chimney. As the outer corrugated skin/cladding heats up on the upper surface, cooler air is naturally “syphoned” from outside through fixed or operable low level eave vents which in turn forces the warmer stale air up the roof / wall cavity, it’s then purged through static ridge vents and optional roof ventilators.
The house power supply is predominantly generated by a stand-alone 6kW solar system generating which is capable of running autonomously for approximately five days. PV (Photovoltaic) cells are mounted on the curved roof which provides excellent flexibility with adjusting the PV cells to the correct sun angle relative to the location.
The two storey prototype house achieves a 6 star rating (CSIRO AccuRate) on the present level of specification. This can be increased to meet individual requirements.
Energy efficient aspects of the Convertible Building include the installation of compact fluorescent lighting, energy efficient appliances and a high efficiency solar water heater has been installed with an LPG booster.
Smart flush toilets and a reed bed effluent treatment system have been located on a lower area to the north of the house site.
Potable water is collected from the expansive roof/wall area and gravity fed into an above ground water tank. Rain harvesting is maximised via the barrel vault roof / wall area, the rain is transferred to the underslung half round gutters adhering to the sheets through surface tension once it travels beyond the vertical plane while the majority of leaf litter and twigs fall off the roof cladding at the vertical position. As the gutter is conveniently located below shoulder height any remaining debris can be easily and safely cleaned. Excess water run-off from the tanks, deck areas and surface water is directed into the existing dam to the east of the house site.
The property is heavily vegetated with native trees and grasses over two thirds of the site and has an “Environmental Significance Overlay” so any further agricultural activities require considered planning.
The innovative structure reduces wastage through its modular lightweight construction and Best Practice Site Management, i.e. labour and material efficiencies; waste water management; waste management and recycling.
The steel framing is prefabricated to standardised lengths and segments for the floor, wall and roof framing.
Installing the roof/wall sheeting horizontally eliminates the additional energy and costs associated with roll forming and makes transportation and fixing of the sheets easier.
Top soil derived from the excavation of the house pad was stockpiled to the north of the house site on an existing grassed area at reduced height to enhance micro-environment and then redistributed over the cut and fill batters and planted with native grasses soon as soon as possible to prevent potential soil erosion.
Materials wastage generated from the construction was responsibly stockpiled for potential recycling.
In order to maintain the highest quality and the integrity of the Convertible Building, where a client has a specific requirement or seeks a change to the standard dwelling configurations provided (i.e. Weekender, Rural/Coastal, Urban, Events Structure), Designology works with the client to ensure the optimum solution.
The customised design process also considers any required modifications to the standard structural components and fixings.