Homeownership provides financial and emotional security and often represents the largest investment an individual will make in their lifetime. Businesses in the House Construction industry build new detached low-density dwellings or renovate and repair existing homes. Over the long term, rising house and land prices have resulted in more homebuyers opting for higher density dwellings, such as apartments and townhouses, which has constrained demand for industry services over the past five years. Australia’s housing demand has been underpinned over the past five years by strong population growth and record-low residential home loan rates. Check out our extensive range of home designs at Hitch Constructions.
What are the different types of construction?
Masonry homes are built from block, stone or brick.
Autoclaved Aerated Concrete (AAC) is a common lightweight block that provides strength and is an excellent insulation and sound blocker.
It can be covered with render, stone veneer or even cladding for an easy and cost-effective finish.
Brick homes typically include an inner wall of a block and outer brick or stone veneer wall.
Wood Framing / Brick Veneer
Wood framing consists of the main structure of prefabricated panels and trusses connected using nails or screws to form walls, floors, roofs and ceilings.
It is low cost and has design versatility as well as being quick and easy to construct.
A drawback of wood is that, if incorrectly treated, suffer damage in the form of rot, swelling, mould or attack from termites.
Being very lightweight, it is quite a poor sound insulator although added insulation can give great acoustic and thermal insulation.
Budget houses can be clad with timber or covered with a brick skin (brick veneer).
This is similar to wood framing but offers more long-term durability and fewer flaws.
It costs slightly more than wood but has a predictable finish that results in straighter walls and a tightly constructed home.
Although steel framing is a thermally conductive material proper detailing can address the problems
Homes constructed with concrete can use cast-in-place concrete, precast panels or insulated-concrete forms that contain integral insulation.
Whichever method you choose, concrete homes provide long-lasting durability and strength with very little maintenance. Concrete constructed buildings require specialist concrete repairs, and this material is most commonly used on heritage buildings.
The restoration can be challenging, but the use of this method offers a high level of fire and pest resistance, and it can withstand high winds and tough storms.
Concrete homes tend to cost more than the more conventional ways to build a house and often require specialist builders to ensure quality finishes.
Eco-friendly built homes include straw bale, mud brick, and earth mound methods.
These homes are energy-efficient and can be built on a budget provided you are prepared to put in a fair bit of effort yourself.
Strawbale homes represent a sustainable and eco-friendly design with enormous potential.
Earth mound homes, including those made from adobe and those sheltered underground, provide another energy-efficient design possibility.
Structured insulated panels (SIPs) are one of the most widely used green construction methods.
They consist of sheets of foam insulated sandwiched between sheets of aluminium, steel, plywood or fibre cement.
These panels form the walls, floor and ceiling of a home to create a virtually unbeatable level of energy efficiency and watertight construction.
A SIP home tends to be well insulated and draft-free, so it needs less energy to heat and cool than a typical stick frame.
This means you will need a smaller heating and cooling system, saving you money and the environment.
What are the construction systems?
The combinations of materials used to build the main elements of our homes — roof, walls and floor — are referred to as construction systems. They are many and varied, and each has advantages and disadvantages depending on climate, distance from the source of supply, budget, maintenance requirements and desired style or appearance.
The environmental performance of a construction system is determined by the life cycle or ‘cradle to grave’ analysis of the impact of the individual materials used in it. Preliminary decisions about construction systems are often made during the early design stages of a project. In contrast, analysis of their environmental performance often occurs later during the detailed specification stage (see Before you begin). Making decisions in this order can limit the range of achievable and cost-effective environmental outcomes.
Similar materials can have vastly different environmental impacts depending on where and how they are sourced. The source of the materials and the way they are processed ultimately determine their environmental impact. Give careful consideration to your choice of construction system early in the project, as changing systems late in the design or construction process can be costly, particularly if it requires structural alterations.
Most of Australia’s new housing stock is built to a common formula that varies only slightly, regardless of climate, geographic location and occupant lifestyle.
The majority of the new housing stock is built to a common formula that varies only slightly between states and cities. The formula prevails regardless of the enormous range of Australian climates, geographic locations and occupant lifestyles.
The formula has developed for a variety of reasons including availability of skills and materials, ease and speed of construction, market perception or familiarity with the final product, and individual or community perceptions.
This approach rarely delivers the most appropriate or even the least expensive solutions for Australian housing needs. It contributes to the environmental and economic cost of our homes and often adds little in the way of improved comfort and lifestyle.
Emphasis is often on ‘borrowed style’ and greater size — at the expense of comfort, function and performance. Finding the right home constructions company Melbourne is an important decision. Check out our range of the best home design constructions at Hitch Property Constructions.
Thermal performance of construction systems
An important point of differentiation between construction systems is their mass content. High and low mass materials make different thermal performance contributions depending on:
- the climate zone they are used in
- where they are used (internally or externally)
- availability or access to passive heating or cooling
- how they are designed to interact with or moderate the climate.
Mass can only contribute to thermal performance when it is exposed internally and insulated externally. When used this way as thermal mass, it can even out diurnal ranges by retaining or shedding heat. Diurnal variations greater than 6°C and access to passive heating and cooling are required for this. Where they are not accessible, low mass usually performs better.
When used externally, such as in brick veneer construction, high mass systems can have other advantages but do not contribute positively to thermal performance. Indeed, they can have a negative impact on poor designs.
High mass systems
- generally have higher embodied energy
- can offset their embodied energy by reducing heating and cooling energy use over the life span of the home
- are most appropriate in climates with high diurnal (day-night) temperature ranges
- can be a liability in tropical climates where energy is used only for cooling
- require more substantial footing systems and cause greater site impact and disturbance
- are often quarried and processed with high environmental impact
- require careful cost-benefit analysis on remote sites where transport needs are significant.
- generally have lower embodied energy
- can yield lower total life cycle energy use, particularly where the diurnal range is low
- respond rapidly to external temperature changes or heating and cooling input
- can provide significant benefits in temperate and hot climates by cooling rapidly at night
- are often preferable on remote sites with high materials transport cost
- often require more heating and cooling energy in high diurnal range climates (where passive heating and cooling is available) due to their inability to moderate diurnal cycles
- can have thermal mass added through the inclusion of water-filled containers or phase change materials
- can have lower production impact if sustainably sourced.
Mixed mass systems
In most situations, a well-designed combination of low and high mass construction produces the best overall economic and environmental outcomes.
In temperate climates, the best overall outcome is most simply achieved with concrete slab-on-ground and lightweight walls. In hot, humid climates, low mass construction is preferable. In cool climates, high mass is desirable. In cold and hot arid climates, careful positioning of low and high mass throughout the building is required to achieve the best outcomes.
High mass lower levels (earth-bermed precast concrete) and low mass upper levels (insulated timber-framed or AAC block) are combined to optimise the use of embodied and operational energy.
What are the elements of the construction system?
Footings are the structures that transfer the weight of the home to the foundation material, most commonly soil. Footing systems must be designed to suit varying geotechnical (soil) conditions and provide adequate tie-down for the building structure under the site’s wind classification. A good system meets these requirements while minimising both site disturbance and the quantities of materials with high embodied energy such as concrete and steel.
Lightweight framed systems have the lowest site impact and embodied energy. A broad range of lightweight steel footing systems is available including screw piles, adjustable steel piers on a simple concrete pad or bored columns, and pole and space frame systems.
Concrete slab integrated footings require substantial excavation on all but level sites, increasing impact. They can reduce construction costs where the slope is low and where the climate allows earth coupling to offset additional embodied energy over the life cycle substantially.
Waffle pod slabs are an effective structural solution were required for geotechnical reasons but should be used only on sites with moderate to reactive soils because the additional steel and concrete used wastes embodied energy on stable sites. Pods can be made from old car tyres filled with compacted fill. This maintained earth coupling, whereas cardboard and expanded polystyrene (EPS) foam systems do not. EPS foam often contains highly detrimental greenhouse gases, with a higher embodied energy equivalent than carbon dioxide. This further increases the embodied energy level.
Detached strip footings combined with loadbearing brickwork to floor level can reduce excavation. However, brick dwarf walls with fill often increase the embodied energy of this system.
Engineered steel pile systems capable of supporting masonry walls are now available. They reduce excavation and site impact and make for faster construction. Cost varies with application but is generally more expensive than strip footings. At HP Constructions, we have the best home constructions selection to make your house a dream come true.
High mass floors
The most common high thermal mass floor system is concrete slab-on-ground. Earth coupled slabs are effective where deep (>3m) earth temperatures constantly remain between 16°C and 19°C. Where temperatures fall outside this range (e.g. Darwin or Tasmania), the underside should be insulated (see Passive solar heating; Passive cooling; Concrete slab floors; Thermal mass).
Other systems include suspended slabs or precast concrete beams with lightweight infill and concrete topping. To contribute positively to thermal performance, the underside of suspended floors, including subfloor spaces, must be insulated if externally exposed (see insulation).
Lightweight suspended concrete floor systems are competitive in cost with timber and steel framed floors and can reduce site impacts where a slab floor is preferable to a lightweight floor. The slab underside must be insulated.
Compacted earth, flagstone or rock (e.g. Coober Pedy in central Australia) is used less commonly. Still, it is equally effective when properly designed and built for climate and site (see Thermal mass). Such systems have either low or no embodied energy and minimal transport impact. Generally low cost.
Low mass floors
The most common form of low mass flooring is lightweight timber or steel framing with particleboard, timber, plywood or compressed fibre-cement sheeting. When designed and built for deconstruction (e.g. screwed, not glued), this flooring has a high potential for reuse at the end of its life.
Lightweight steel framing has higher embodied energy than timber but is highly recyclable at the end of its life. Steel framing has greater durability in termite prone areas and often has lower transport costs than equivalent timber structures. It is subject to rust in corrosive environments; galvanising can eliminate this but does add to embodied energy. Usually more expensive than timber.
Lightweight timber framing using sustainably sourced plantation timber is a carbon sink effectively minimising embodied energy. Engineered timber bearers and joists allow for highly efficient use of materials, but glues can have a detrimental effect on indoor air quality and human health. Timber is subject to termite attack and, while termite proofing reduces this risk, it often relies on chemical treatments that have other environmental implications. It is relatively low cost.
Engineered composite panel or structural insulated panel (SIP) systems are growing in popularity. Low mass insulation materials are bonded to lightweight steel or ply sheeting and usually achieve high levels of structural efficiency with inherently high insulation levels. Cost ranges from medium to high depending on the system.
Many of these low mass floor systems offer lower embodied energy, increased structural efficiency and reduced resource depletion when sustainably manufactured from environmentally preferred materials.
Composite mass floors
Common examples of composite mass floors are:
- lightweight frames topped with concrete
- lightweight systems with water-filled inserts to provide thermal mass
- autoclaved aerated concrete (AAC) floor systems (see Autoclaved aerated concrete)
- phase change materials embedded in low mass materials to produce lightweight flooring with high thermal storage capacity (see Thermal mass; Mud brick).
High mass walls
Common high thermal mass wall systems are masonry and include brick, concrete block and precast concrete. Other popular systems include rammed earth and mud brick.
Traditional masonry systems generally have high embodied energy while rammed earth and mud brick have significantly less. Rammed earth uses varying levels of cement depending on earth type and therefore has higher embodied energy than mud brick (see Rammed earth; Mud brick).
All high mass wall systems must be externally insulated and internally exposed to improve thermal performance. Insulation levels depend on internal-external temperature differentials. The higher the temperature differential, the more insulation required (see Insulation; Thermal mass; Passive design).
Thermal lag (i.e. the retention of heat or cold) in thick walls such as rammed earth or mud brick can reduce the insulation level required in mild climates but may not eliminate it. This is a common misconception about these systems. Significant external insulation is required in cold climates, and their use should be avoided in hot, humid climates. Thermal performance modelling determines climate appropriateness and appropriate insulation levels.
Low mass walls
The most common form of low mass wall construction uses lightweight timber or steel framing as the structural support system for non-structural cladding and linings such as fibre cement, plywood and steel. Insulated lightweight walls reduce heat loss and can have minimal embodied energy, depending on the cladding material used.
Fibre cement sheet, plywood and other sheet cladding systems have low embodied energy and generally low environmental impact. They are very durable — although maintenance is required for any painted surface (see Embodied energy).
Composite (mixed) mass walls
These systems fit between high and low mass with either moderate density, such as AAC where high mass concrete is used to trap tiny (no mass) air bubbles or a combination of high and low mass, like straw bale where straw is a low mass, and the render finish is high mass.
Autoclaved aerated concrete, or AAC, contains closed air pockets that make it lightweight and fairly energy efficient.
Log wall construction — a low mass system — is one of the oldest methods of building, dating back to prehistoric times. It developed as a natural consequence of having a plentiful supply of tall, straight timber that could be relatively easily cut and worked and turned into building components. It is historically associated with countries and regions with tall pines and similarly straight-trunked trees. It appears to have first developed in northern Europe and spread with European colonisation, notably to North America where the indigenous pine forests provided plentiful timber suited to the method.
A solid timber log home.
Australian log homes use solid timber logs. At least one supplier uses imported Scots pine and Norway spruce, laminated when wider logs are needed; others use Australian white cypress or Monterey pine (Pinus radiata), which is native to the central coast of California but widely grown in Australia as a plantation tree. Systems of log wall construction that use composite ‘logs’, each made of a timber plank sandwiching a layer of rigid insulation behind an outer face or veneer of the natural log, have yet to enter the Australian market. A variant on the log facing technique is used on ‘log veneer’ houses in which logs are cut lengthwise to create cladding on insulated stud frames with timber panelled interior faces.
High mass roof systems
Roof systems are unable to improve thermal performance in thermal mass terms unless they can be exposed internally and insulated externally. Because ceiling level insulation is critical, exposed roof mass is unusual except in multi-level homes or apartments.
Low mass roof systems
The performance of lightweight timber or steel framed roof systems is similar to walls and frames. Variations in embodied energy arise from cladding systems that do not contribute to thermal performance.
There are a variety of house construction methods available for your new build.
Most Australian builders are used to building brick veneer, except for Western Australia masonry(double brick), double are more popular.
It’s the great Australian dream – building a house from the ground up, but the process of construction can be a bit of a mystery, especially for first-home owners.
Knowledge is power, so understanding the construction phase – what will happen when and how – is one of the best ways to minimise anxiety and start to enjoy the process.