Residential Design in Sutherland Shire - Concrete Slab vs Timber Flooring

If you’re planning on building a new home or simply doing an “alterations and additions” renovation to your existing house (for example adding a new first floor to your single-storey home), one of the earliest and most critical decisions you need to make is whether your new floor will be of a concrete slab or framed with timber joists. So what’s the difference, and what are the pros and cons of each?

There are many things to consider in such a decision, we'll break in topic into 2 blog posts. Leet’s look at the first few of the influencing factors:

1. Cost

Generally speaking, a concrete slab is going to cost you more money to build.  Whether it’s a slab-on-ground for your Ground Floor, or a suspended slab for your First Floor, a concrete solution is going to cost more money because of 'materials, labour, and time'.  A slab will require formwork, steel reinforcement, pump hire on the day of the pour, and finishing costs becuse you will still need to build either a solid timber floor or lay tiles or carpet over your slab once it’s poured.

In contrast, a timber-framed floor (which might consist of bearers and joists that sit on brick piers at Ground Floor, or perhaps simple timber joists that span from wall-to-wall at First Floor level) can be easily installed by a carpenter; readily handled on site; cut to length as required; and is also more flexible for future alterations or renovations.  Timber is certainly the more affordable solution if your budget is squeezed.

 2. Performance & Durability

Concrete is a stronger and more robust material.  Compared with a timber-joisted floor, a concrete slab will exhibit less bounce, vibration, and noise-transmission through the floor when subjected to foot traffic – and if you’ve got young kids who jump around upstairs whilst you’re trying to relax downstairs, then this is something you may wish to take into account!   If your floor features stone or ceramic tiles, then we’d also recommend a concrete slab – a timber joisted floor will be more prone to bounce and deflection, which risks cracking the tiles.  Depending on other features of your house, a concrete slab can also offer better performance in terms of thermal mass and insulation.

Timber is a natural product, and it needs to be treated accordingly.  Depending on your design and the features of your house or the site, waterproofing, ventilation, and durability need to be considered.  The majority of timber used for framing in the construction industry these days is softwood – typically radiata pine.   Whilst this is cheap, renewable, and readily available, it’s also entrée, main course, and dessert for termites!   The termite treatments and barriers in use today are vastly improved and more effective than in yesteryear, so this isn’t necessarily cause for alarm, but it’s certainly something you need to take into account if your area is a known termite hotspot.

Mind you, concrete doesn’t get a complete tick here either – the steel reinforcement within the concrete needs to be placed and cast in with appropriate cover for protection.  In aggressive  environments, such as suburbs near the sea or Sydney Harbour, airborne salts & moisture can penetrate the concrete and lead to corrosion of the steelwork.  As the steel rusts and expands, it can cause spalling (breaking off) of the concrete, requiring expensive remediation and repair work.  (This is the defect many people refer to as concrete cancer.  We’ve previously written about concrete cancer here.)  Of course, providing your engineer specifies the correct grade of concrete for your site, and providing the builder places the reinforcement with adequate cover at the time of pouring the concrete, you won’t have a problem.

Finally, whilst it’s not a pleasant thought, some people also give consideration to what happens in a house fire.  Needless to say, a concrete slab is less combustible than a timber floor.

What's Next?

Contact us at Go Design Solutions, the Sydney's specialist in residential drafting design. Located in Penshurst and Sutherland Shire, Go Design Solutions are experts in residential drafting services in sydney and any general drafting services in Sydney. We provide an on-stop shop from Sydney residential drafting, to DA submission and liasise with all consults to get your residential extension in Sydney or a new home building in Sydney done in the proper way! We know what we do best and provide residential drafting services for our Sydney clients.