Green guide: steel versus wood framing
While wooden framing has been the standard method used in Australian home construction for years, the use of lightweight steel to frame residential structures is on the rise according to a number of industry sources.
|However when it comes to deciding on the framing to be used in your new home, it’s important to consider the advantages and disadvantages of both materials – after all, this is what’s holding your home together.
Sustainable construction: to steel or not to steel?Opting for steel framing can ensure the longevity of a home – it’s stronger and more resistant to fire than timber, and according to Steel Framing Australia can also cost less to insure.
Steel doesn’t warp, rot or split, and it’s white ant and vermin proof . Somewhat surprisingly, it also creates a 100% recyclable waste product.
While still relatively new in the residential building, steel is a veteran of the commercial construction industry. It has been developed to include consistent wiring, insulation and connection standards and can be used for larger spans than timber.
However, the majority of contractors and builders have little or no experience working with steel framing, which requires different tools and a different skill-set. (There could be a few nervous phone calls from your builder if you decide on steel).
Steel is more expensive than wood, and once on site, it can be difficult to alter. The metal framing can also make a home less energy efficient as it acts as a heat conductor – meaning the occupant will be forking out more for heating and cooling.
(To get over this, builders use a series of thermal breaks. Read more about this next week when we talking about thermal bridging.)
Adding to this, the US Department of Housing and Urban Development has commissioned an interesting report to give builders and owners looking for sustainable building materials a way to compare the thermal performance of the two materials.
Sustainable housing: what about the wood?Despite the issue surrounding the recycling of treated wood – we cover this in more details in a recent story with sustainable designer/builder Brett Blacklow
– many sustainable designers claim building with wood framing is one of the primary building blocks – yes excuse the pun! - in creating a “green” home.
One of the reasons is that a timber framed home has the potential to be more energy efficient, because the thermal transfer of heat tends to be higher in steel homes than timber ones. This can mean that with the same amount of insulation and air conditioning a timber framed home is cooler in the summer and warmer in the winter.
In addition, with most of the timber used in Australian homes sourced from renewably plantations, rather than old growth forests, timber has a much smaller carbon footprint than steel or brick says the Timber Development Association.
In addition, timber framing is the most common method used in residential construction throughout Australia – so you won’t receive any blanks stares when you ask for timber framing from your contractor. Builders are familiar with it, have the tools to work with it and can easily alter it on site.
On the flip side, because wood is a natural product, it’s less uniform in its strength characteristics with knots and flaws. It’s also combustible and susceptible to decay and insect damage.
For more information about modern timber frame properties and their common problems, check out this article.
Recycling timber framingRecycling timber is a labour-intensive process and the chemicals used to treat timber require careful disposal – and as a result, wooden building waste often ends up in the local landfill rather than the correct facility. The adhesives used with building timber also complicate the recycling process.
While timber frames feature less embodied energy, once you’ve considered that less steel is required to construct a new home and takes up less space in landfill, the embodied energy margin is narrowed significantly.
An article previously published on LightHome includes an interview with David Baggs, CEO of third part material certifiers Global Green Tag & Eco Specifier. He provides insight into the complex embodied energy issue.