Alternatives Materials to Traditional Double Brick Walling

If you are planning to start a new home construction or renovation project, you most definitely would have been faced with so many choices of building materials, house components, and building methods that are available today among other aspects involved in new builds and renovations. It certainly can be overwhelming but the trick is to analyse all the available choices and understanding their pros and cons.

Some factors that you should consider while reviewing and selecting construction materials include strength, availability, durability, workability, ease of transportation, cost, aesthetics, resistance to fire, climate, sustainability, maintenance, and ease of cleaning. You should also consider factors influencing economy of building materials including availability of material, source of material, cost of raw materials, manufacturing costs, transportation cost, cost of placing and maintenance cost.

The above factors should be considered for all building materials required for the new build or renovation, some materials warranting more thought than others, including foundations, superstructure, walling, windows, doors, roofing, interior finishes, flooring, tiling, paint, kitchens, bathrooms, door hardware, decks, driveways, fences, gates, plumbing, electrical and lighting.

Of all the materials choices, one of the most important is the choice of wall material and construction method. The two most common wall material choices and construction methods in Australia are double brick and brick veneer, with Western Australia seriously obsessed with double brick construction method. Majority of homes in Perth are double brick, a classic, durable material considered by many to be a premier choice for home building. Today, Perth is the only Australian city still building mostly double brick homes.

According to the Australian Bureau of Statistics, in the last 100 years or so there has been a long-term shift away from timber towards brick as the most popular material for outer walls in Australia. In 1911, 25% of outer walls were made of brick, in 1981, 58% of dwellings had outer walls made of brick, and by 1994, 65% of dwellings had outer walls made of brick and 87% of new dwellings had outer walls of brick. In 1993-1994 Western Australia led the way with the highest percentage (87%) of new dwellings constructed with outer walls of double brick of all states and territories, compared to New South Wales’s 13% and Victoria’s 1%. Results from a recent survey conducted by the Department of Housing and Department of Planning and published in the 2013, The Housing we’d Choose: a study for Perth and Peel show that approximately half of respondents prefer double brick as a building material for their homes.

Double Brick Walling

The two brick walls possess an air gap or cavity between them which reduces heat transfer and prevents the penetration of moisture from the outside walls to the interior of the house. In some more energy efficient houses, the cavity can have an insulation to further reduce heat transfer. In the construction of a double brick wall, two walls are built that are joined with brick ties. These ties can either be of steel or any other strong material to strengthen the structure of the walls. The inner walls are usually made of brick or concrete blocks that are coated or plastered with a lining board. The thickness of the inner walls is 90mm. The thickness of the outer wall could be around 110mm. The cavity between both walls is 50mm. These parameters make up the double brick wall of thickness around 250mm.

Advantages of Double Brick Walling

  • Double bricks are extremely durable and require very little maintenance.
  • In the case of a natural disaster such as earthquakes, violent storms, floods or tsunamis, double brick provides a much more stable structure. 
  • They act as an insulator and keep your home relatively cooler and warmer in summer and winter, respectively.
  • The cavity or air gap between double brick walls not only reduces the thermal transmission and avoids moisture penetration, but also acts as a barrier to lessen outdoor noise pollution. 
  • Home with a double brick wall construction does not include any wood frame, therefore there is less probability of pest attack such as termites.

Disadvantages of Double Brick Walling

  • Higher building costs – double brick construction is generally more expensive compared to other methods including brick veneer. Double brick homes require massive foundations to take all of that weight, which requires a lot of concrete and reinforcing steel. On top of these costs, you also have to pay for the extra site administration and supervision, as well as the scaffolding, site amenities and utilities for 7-10 months.
  • Reduced energy efficiency – a full masonry construction requires materials with significantly more embodied energy than a timber frame home, meaning that more energy is used in the production and transport of these materials. Brick homes also have a higher thermal conductivity than timber and require more energy to keep them cool in summer and warm in winter.
  • Slow completion times – the single most alarming complaint from new home owners is the length of time it takes to complete. A double brick home can take up to 10 months to complete, leaving home owners with months of rent to pay and extra interest on their home loans. On the other hand, a timber frame and other engineered timber products construction takes just 3-4 months to complete for a single story home and 4-6 months for a double story. In addition, due to the nature of double brick, home remodelling and extensions can be a bit difficult.
  • Smaller homes and less usable living spaces - a full double brick wall is 60% wider than an equivalent timber framed wall, which means that you have less usable living space with a full masonry build than with a timber frame. With the size of lots being continually reduced in Australia, this means that you either build up to the boundary or have a smaller building footprint. Regardless of your choice, a double brick construction leaves you with smaller living spaces than a timber frame home.

Alternatives to Double Brick Walling

The walls of your home – inside and out – can be constructed from or clad in an enormous variety of materials. As one of the largest parts of the home, the walling material you choose will have a huge impact on the cost of your build, how quickly work progresses, your home’s environmental footprint and ongoing energy efficiency. Aesthetics are a major consideration too, with different materials suited to different architectural styles. Traditional double brick homes are slowly being replaced by structures built using new materials and alternative forms of construction particularly in Western Australia. Below are some of the key alternatives that you should definitely consider:

Brick Veneer

Brick veneer isn’t a term you often hear in WA, but it’s readily used in every other state of Australia. Brick veneer is also the most common type of construction for Australian homes. It can also be called masonry veneer. A brick veneer home uses a timber or steel frame as the internal structure. The brick or masonry veneer over the frame is the skin of the home. The veneer is anchored to the house frame for support with using either metal ties or horizontal header bricks. Construction consists of a brick layer that is mainly used for waterproofing that is connected to the internal stud frame with ties which make up the strength of the house. Two main components are involved in Brick veneer house construction:

  • The Frame, which is the core structural component of the building and provides support to the house roof. Steel or timber material is used to make up the frame. 
  • Brick, even though the name suggests that it is solid, but it only supports itself and makes use of ties to keep the frame stabilised. It acts as a weatherproof skin and protects the building.
Advantages of Brick Veneer
  • In terms of cost, brick veneer is generally less expensive compared to double brick.
  • A wall that is made of brick veneer is lightweight and thereby reduces the cost of structural foundation requirements.
  • In years to come when the homeowner wants to move an internal wall, it’s much easier if it’s a steel or timber stud wall compared to brick.
  • The cavity between the veneer and frame makes adding insulation very easy.
  • They brick exterior allows the house to have a solid aesthetic look.
  • The house doesn’t retain the heat and can cool down easier on a summer night compared to a double brick house.
  • The builder needs less time on site if the home uses a timber frame construction compared to a bricklayer building a double brick house.
  • In states that have clay soils, the house can move with the changing soil moisture levels. Brick veneer is not as rigid as a double brick, so it has more tolerance for movement.
Disadvantages of Brick Veneer
  • Brick veneer does not provide the best level of thermal transmission.
  • If you make use of a timber frame, there is a higher chance of termite attack.
  • Brick veneer can be noisy and has a hollow sound when touching internal walls.
  • While the home looks strong, it doesn’t have quite the same strength of a double brick home.

Timber Frame

While these days most timber frame construction involves the use of prefab house frames, in some cases the task is still completed on site. The timber framing is supported by a substructure of piers, piles, stumps, posts, stud walls, dwarf brick walls or perimeter masonry walls.

The most common technique used to construct timber framed homes is known as platform framing. This involves attaching planks of timber (studs) to other pieces of timber that lie across their tops and bottoms (wall plates). In Australia, timber wall frames are typically either 90mm or 70mm deep with 35mm or 45mm thick studs depending on load and spacing — usually 450–600mm. Noggins (spacers) are inserted between studs to provide lateral support.

The next step is to ensure the timber has the required stability. This involves attaching a strong and flexible material, usually plywood or oriented strand board, to the outside of these studs; and then fitting struts diagonally between the studs. At this point, the timber frame is complete, though still lying on the ground, and it is ready to be raised and lifted into position on the completed foundations. The ceiling joists and roof rafters can now be attached, and the house is ready for utilities, floors, walls, and internal and external finishes.

Advantages of Timber Frame

A natural, renewable product, timber is completely non-toxic. It is safe to work with and poses no threat to the homeowner or tenant. And, here in Australia, consumers can rest safe in the knowledge that most timber used in timber frame construction is ethically and sustainably sourced. Consumers concerned with verifying this can check with certifications such as Programme for the Endorsement of Forest Certification (PEFC) or the Forest Stewardship Council.

Timber has a very low embodied energy rating (the lowest of any of the major building materials) and actually stores approximately half its dry weight as carbon. On top of that, it is a good insulator. It has a high R value and does not act as a thermal bridge, causing unwanted heating or cooling. In short, used sustainability, timber can be part of the environmental solution.

In terms of construction, the news is also all good. Reliable and cost-effective, timber frame houses are well understood by specifiers. Carpenters are well-versed in its use and the system lends itself to changes and variations on-site. It is easy to work with, it involves low labour costs and generally poses few difficulties during renovations or extensions.

Disadvantages of Timber Frame

However, timber frame construction does have its down sides. Unlike steel alternatives, it does burn. However, while this is true, it can be noted that it is generally encased by material such as brick (externally) and plasterboard (internally). In a fire it chars at a predictable rate.

Similarly, while timber framed homes are susceptible to termites and white ants, the use of a termite barrier system minimises the possibility of this problem even in areas deemed high risk.

Metal Cladding

Suitable for exterior walls, metal is a surprisingly versatile decorative wall finish that is currently enjoying a moment in the design spotlight. Architects are creating a sleek, industrial aesthetic using steel, copper, aluminium or zinc, applied in flat sheets or panels. As an exterior wall-finishing product, some metals are relatively lightweight and durable, and it requires little maintenance and should retain its good looks for many years to come.

Metal cladding is supplied as a series of interlocking panels that are affixed to the exterior of the building. It can be applied in a variety of formations to create different visual effects, and each metal has its own unique character and properties. Metal cladding comes in a wide range of finishes, from shiny and reflective right through to matt, powder-coated colours.

Advantages and Disadvantages of Metal Cladding
  • Little maintenance is required (a quick wash and it’s good as new).
  • Some metals, such as zinc, will develop a patina over time.
  • Some manufacturers offer products made from recycled metals.
  • Metal is waterproof and requires no further finishing once installed.

Fibre Cement

Suitable for exterior walls, fibre cement is a type of wall cladding material that is durable, weatherproof, resists rotting and warping, and is termite-resistant. It is sold in a wide variety of formats and finishes, from large panels to weatherboard-style planks. This makes it well suited to a range of architectural styles, from ultra-contemporary right through to classic, heritage-inspired looks. Fibre cement boards are made from a mixture of sand, cement and cellulose fibres, and can be relatively heavy to lift and manoeuvre during construction.

Australia’s love-affair with Hamptons-style architecture continues unabated, and fibre-cement weatherboards can deliver the requisite traditional aesthetic without too much ongoing maintenance. As well as standing up to weather extremes, fibre cement boards will resist termite attack and are non-combustible. These boards can be supplied in a range of decorative profiles and finishes, including smooth and embossed with wood-grain texture. Some brands pre-prime the boards ready for painting.

Advantages and Disadvantages of Fibre Cement
  • All fibre-cement cladding products are engineered for fast, easy installation. However, their durability and weatherproof qualities are reliant on correct waterproofing preparation and installation procedures, so it’s important that your builder has prior experience in working with the product.
  • Fibre-cement boards are generally quite thin, so they don’t offer any inherent insulating properties or thermal mass. This means additional insulation will be required.

Hempcrete

Suitable for exterior and interior walls, made from a mixture of shredded hemp stems, water and lime, hempcrete (or hemp masonry) is a super-sustainable building material that has the potential to revolutionise the way we build. An innovative cousin of traditional rammed-earth construction, building with hempcrete involves pressing the hemp mixture between structural timber framework posts. A wash of lime-based render seals the product in and creates a smooth, seamless finish.

Hemp masonry is thermally efficient and provides good levels of insulation for ongoing energy efficiency and reduced running costs within the home. It’s also non-toxic, breathable and can reduce internal humidity levels, which translates to healthier indoor air quality.

Aesthetically, hempcrete has a beautifully organic, raw appearance and tactile warmth. It can be left natural throughout most of the interiors, however wet area and external walls will require a layer of waterproofing in the form of a breathable sealant or specialist lime-based render.

Advantages and Disadvantages of Hempcrete

Hempcrete is a holistically sustainable wall solution. Not only will it deliver a well-insulated, thermally efficient and low-energy use home, but hemp is a fast-growing crop that sequesters carbon as it grows. Hempcrete itself continues to absorb carbon as it cures.

Building with hempcrete is still very new; the product is expensive and finding a builder who understands the technique may be difficult.

Concrete

Suitable for interior and exterior walls, as a wall finish, concrete is as handsome as it is durable. Its imposing presence and versatility as a building material have seen it transition from commercial buildings into the residential sector over the past few years.

Concrete homes can be constructed in two different ways – from tilt-up panels that are poured on-site then erected; or from pre-cast panels that are produced off-site and transported in. While each method allows for high design flexibility, tilt-up is a preferred option for many architect-designed custom homes, as it allows total control and almost limitless options – panels can be poured to any thickness, shape, height and textural finish. However precast options can also be manufactured in a variety of shapes and sizes, and can be tinted with oxides or formed with aggregates, such as pebbles or stones, to create different looks.

Concrete is durable, non-combustible, termite-resistant and will require almost no maintenance. It offers excellent thermal mass, meaning it will help to stabilise temperature fluctuations inside the home.

Left exposed on the interior walls, concrete introduces an edgy, urban feel. While it’s a bold design statement in itself, its soft, neutral colouring and subtle texture also create the perfect backdrop for colourful artwork and statement furnishings. It also pairs beautifully with other raw finishes, such as timber and natural stone.

Advantages and Disadvantages of Concrete
  • Building with concrete requires engineering expertise and an experienced builder.
  • It can be expensive. If heavy panels need to be transported and/or craned into site, costs can quickly escalate. Using the tilt-up method reduces transportation costs.
  • Using pre-cast or pre-fabricated panels will reduce on-site construction times.
  • Once installed, concrete walls will require no further finishing, making it the ultimate maintenance-free material.

Besser Blocks

Suitable for interior and exterior walls, much cheaper than concrete but offering a similar hard-edged aesthetic, besser blocks – also known as breeze blocks or masonry blocks – are typically rectangular, hollow concrete blocks. Light yet strong, they are a versatile, inexpensive, and surprisingly under-rated option for walls. The holes in the centre of besser blocks offer several advantages – they can be reinforced with steel and filled with concrete to improve structural stability, or left unfilled, they provide space for plumbing and electrical wires in internal walls. The air space also delivers improved insulation.

While the plain appearance of undressed besser blocks may not be to everyone’s taste, designers are increasingly finding innovative and creative ways to use them as a decorative feature. For instance, designers can flip the besser blocks on their side to create a stunning perforated feature wall to the alfresco area. Besser bIocks have a utilitarian aesthetic that works well with exposed timbers and polished concrete. The cool grey-block feature wall can deliver a pared-back elegance to the living areas.

Advantages and Disadvantages of Besser Blocks
  • Besser blocks are economical and highly efficient to build with.
  • Can be laid in different ways to create different visual effects.
  • Homes built with besser blocks may have problems with internal moisture, so a correctly installed vapour barrier is essential.
  • If the utilitarian appearance of besser blocks offends, consider painting or rendering them.

Autoclaved Aerated Concrete (AAC)

Suitable for interior and exterior walls, AAC is a light but strong concrete product that contains hundreds of tiny bubbles or air pockets. It was invented in Scandinavia in the 1920s and has been available in Australia for about 20 years. AAC is manufactured as blocks that are strong enough to be used to construct an entire home (so the interior-facing side of the block wall becomes the interior wall). It is also supplied in steel-reinforced panels. These panels can be used as a veneer on the facade of a home (attached to a steel or timber frame), and can also be manufactured as a complete structural building system including panels for the floor, roof, interior and exterior walls. This type of system enables speedy construction.

Advantages and Disadvantages of AAC
  • It’s highly workable, and can be easily cut and shaped using hand tools. AAC blocks can be used to create curved walls and interesting shapes.
  • The air pockets in the AAC blocks or panels make it an excellent insulator, helping stabilise a home’s internal air temperature.
  • AAC is non-combustible and suitable for use in bushfire-rated areas.
  • Using the panel system may be more expensive than some other building methods. The extra cost may be offset by faster construction times.
  • AAC blocks and panels will need to be finished/painted with specialist protective acrylic coatings.

Structural Insulated Panels (SIPs)

Suitable for interior and exterior walls, SIPs are strong, prefabricated modular panels that slot together to form the walls, floor and sometimes roof of a home. SIP-constructed homes do not require any timber or steel framework – the panels themselves form the structure. This speeds up on-site construction times and reduces labour costs compared to traditional building methods, and because of this, construction using SIPs is rapidly becoming a mainstream option.

SIPs are made from a thick foam ‘core’ sandwiched between two sheets of rigid material. Most commonly, this is a composite engineered-timber product known as oriented strand board (OSB). However, more and more manufacturers are bringing SIPs products to market, using a variety of outer sheeting materials, such as fibre-cement sheeting or plywood.

Advantages and Disadvantages of SIPs

OSB is not waterproof, so depending on what the rigid outers of your SIP product are made from, you may have to install an additional cladding product to the exterior walls, which can increase costs. Inside the home, however, this isn’t an issue, and you can save time and dollars by leaving the face of the SIP walls exposed.

Structural Insulated Panels (SIPs) are available in a range of pre-cut standard sizes, or can be custom-manufactured based on your house or extension design. Thanks to their thick foam core, Structural Insulated Panels (SIPs) offer excellent insulation properties and there is no need to include additional insulation during construction.

Disclaimer

Information provided in the text above is general in nature and does not consider your specific building materials and construction methods needs and requirements. The information is not professional advice and should not be treated as such. You must not rely on the information in the text above as an alternative to professional advice. If you have specific questions relating to this subject, we strongly recommend that you seek independent professional building materials and construction methods advice.