The Australian Dream Series


Construction methods

Construction methods employed throughout Australia fall mainly into the catagories of Solid Brick, Brick Veneer, Clad Frame and Post and Beam construction.
Flooring methods are for the main either concrete slab or stumps.
Roof framing either a truss or a pitched system

The picture above shows a concrete slab on ground flooring system ready to take, in this case, a brick veneer cladding on a timber frame with timber framed internal walls.
The same system, with a 'heavier' slab design could be used for a solid brick home or a 'lighter' slab design for a weatherboard home.
All foundations are designed taking into account the soil type together with the cladding type.
Slab type construction is popular in that it provides a good working plaform for the remaining construction process, problems with subfloor timber shrinkage are removed and on flat sites it is generally a more economical flooring system. A slab can take the same floor finishes as a timber floor such as carpet, tiles etc plus timber floor boards for those looking for a polished floor board effect. - a floating flooring system.
Some people find a concrete floor harder on the feet than a timber flooring system as there is no flexing. Others like the fact that there are generally less steps.
With a timber flooring system (stumps, bearers, joists) the main method now used is 'platform flooring', where the floor is laid before the wall frames are erected. This, as in slab construction, makes for a safe working platform and also speeds up the construction process. The floor is usually a sheet product treated to withstand exposure to the weather until the home is to lock-up stage and water proof.
A drawback with this system is that the flooring is purely structural which does not present a problem for areas that are to be tiled, carpeted etc, but is, where polished boards are desired.
It is possible to apply a clear protective coating to strip flooring but this is rarely successful due to the physical damage that can occur during the framing and roofing stage. Where polished boards are required they can be laid over the structural flooring.
The older method of cutting in the floor boards to individual rooms after the wall framing is completed is now not often used.

Where a timber framing system is employed seasoned timbers are now used extensively for subfloor, wall and roof framing in preference to 'green' timber. These seasoned timbers are lighter, easier to use, are dimensionally uniform and remove or at least reduce maintenance that was regularly required within the first 3 months of a home being built when using green or unseasoned timbers due to shrinkage.

The framework shown above is of seasoned radiata pine with the roof trusses in the same material. The panels either side of the opening are plywood sheets used extensively in external walls on brick veneer homes as bracing.
Many Builders are now also opting to use treated timbers in framing as safeguard against termite attack.
Another option is to use a steel framing system for all structural members.

This picture shows a timber framed home with Hebel aerated concrete panels being installed.
The meter box is in position towards the front corner of the panels, sheet bracing is in place beside the opening together with horizontal battens for the fixing of the remaining panels.
With all these methods whether it be using weatherboards, rendered cement sheet, bricks in a brick veneer construction or in this case Hebel panels, the timber frame does all the structural work supporting the roof loads.

In a solid brick home the external wall load is carried by the inner brick skin.
In a post and beam type construction as shown below the posts are designed to support a structural perimeter beam around the home which in turn carries the roof load. This system is used extensively in mud brick or straw bale construction where the external cladding is classified as an infill panel and is non load bearing.

A post and beam type construction. In this case being for straw bale infills the posts are replaced by 450mm deep panels to stack the bales within. The perimiter beam size is determined by the spacing of the posts or panels together with the weight of the roof load. ie tile roof or a lighter steel roof.

A typical truss roofed frame showing the external wall frame with a double top plate.
With a truss roof system all loads generally are on the external walls - the truss is not supported by any internal walls.
Both internal and external wall frames are made to the same height for convenience and then an extra top plate is installed to the external walls to 'lift' the trusses so that there is no loadbearing points to the internal walls.




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