The Ultimate Guide to Steel Frame vs. Timber Frame

Steel frame vs. timber frame? This can be a daunting question for the uninitiated, so let us help you break it down with our ultimate guide to steel frames vs timber frames.

When designing a new home or embarking on a knock down rebuild there are a number of things to consider, not least of which the material to use for your new house design’s frame. Every project has a different set of requirements and every place a unique set of environmental factors and constraints. In order to make an informed decision on materials you need all the facts, so here is the ultimate guide to steel frames vs. timber frames to help you pick which one is right for your new home design. 

Which is more cost effective?

The short answer: timber. However it pays to consider the overall cost of the home over time due to maintenance requirements. On a materials front the answer is simple, the raw cost of steel is more expensive than timber. However offsite prefabrication for steel frames means that onsite labour costs are reduced. There’s also no need to treat steel with pesticides or other chemicals, it’s lightweight and durable making it practically maintenance free, which can drive the overall cost of the home down over the years.

Timber frames cost less to produce and are much more versatile when onsite. This results in the average cost of a timber frame being around $150-200 per metres squared for a single story conventional home in 2021.

Which one is more time efficient?

Computer modelling and prefabrication allows engineers to tailor steel frames specifically to your new home design and easily meet structural requirements, however this is at the cost of reduced onsite flexibility. Steel saves time-spent onsite but takes much longer in the prefabrication phase. Timber frames require more onsite labour however they can be easily sourced and quickly constructed increasing the efficiency of the build and saving time in the prefabrication phase. Opting for a timber frame also means you have the flexibility to make little changes such as adding a shower niche or recessed mirror cabinet as the build is ongoing.

Timber gives you the flexibility to make small changes during the building process. How to choose the best builder in Canberra

Is a steel frame or a timber frame more energy efficient?

The thermal conductivity of a building refers to the degree in which a material transfers heat and responds to external temperature fluctuations. When planning a knockdown rebuild or new home design you want to choose a material that has low thermal conductivity so it transmits as little temperature change to the rest of the building as possible. It is the role of insulation to counteract the thermal conductivity of the frame material.

Timber frames tend to have better thermal performance because wood is a natural insulating material and has poor conductivity. Steel has high thermal conductivity and responds more intensely to temperature changes in the surrounding environment. This greater response to temperature fluctuations means that a steel framed home has a greater chance of interstitial condensation, which is condensation that occurs in an enclosed wall or roof cavity. If you live in an environment with large temperature fluctuations timber is the more energy efficient choice, as it is a natural insulating material meaning it will cost less to heat and cool your home. Another consideration is that from Total Building Materials Emissions worldwide, 28% of that is from insulating and sealing components; therefore it is a more sustainable choice to choose a frame material that has a lower thermal conductivity, requiring less insulation material.

Timber for days at Home by Howe’s custom house build in Burra.A dream family home in Burra, NSW

What is the environmental impact of steel frames vs. timber frames?

The greater tensile strength of a steel frame means that it can convey a heavier load with less material used, meaning that there is less need to cut into the ground reducing its impact on the site. Steel is also 100% recyclable, however this is offset by the large amounts of energy required in its production process, resulting in a sizeable carbon footprint.

Emissions produced in the fabrication of materials are one of the principal contributors to total Green House Gas emissions, with steel fabrication representing around 4% of total Global Warming Potential. In this case timber frames remain the more environmentally friendly option as a natural product. Results indicate that timber frames have lower embodied carbon emissions; through timber’s ability to retain C02 and less energy intensive industrial processing. Replacement of aldehyde compounds for wood treatment processes with natural resins such as Copa, Dammar, Mastic and Venice Turpentine will also increase the sustainability of your new home design. In summary the carbon storage potential of timber frames has the possibility to produce a net environmental benefit.

Is a steel frame or a timber frame stronger?

Steel frames allow for creative and flexible designs not possible with timber frames. They are also more resistant against flexing and warping allowing for straighter lines and finishes. Durability is one of a steel frames greatest selling points, it has a higher tensile strength, is non-combustible and has greater longevity in disaster prone areas. Timber frames can be more susceptible to termites, borers and pests, which can drive up the overall cost of a home over time.

Theoretically steel framed kit homes should have less movement as they are constructed with fixed brackets, screws and bolts. However due to the severe fluctuations in Canberra’s temperatures over the year, this actually proves counter to the common theory in the ACT. With temperature fluctuations between -4 degrees Celsius in winter and 40 degrees plus in summer the best Canberra builders know that steel framed homes tend to move more than their timber framed counterparts. This movement due to greater thermal conductivity denotes that some lightweight cladding instructions require additional barriers between the steel frame and the cladding, to manage the movement; a consideration that is over and above the requirements for timber frames.


We hope this has helped you to make a more informed decision on a steel frame vs. timber frame when planning your knockdown rebuild or new home design. Due to the large temperature fluctuations experienced over the year in the ACT, the best builders in Canberra such as Homes by Howe recommend a timber frame.

Book a design consultation package with us to make sure you’re making the right decision for your knockdown rebuild or new home design.

Sources

Padilla-Rivera, Alejandro, Ben Amor, and Pierre Blanchet. 2018. “Evaluating the Link between Low Carbon Reductions Strategies and Its Performance in the Context of Climate Change: A Carbon Footprint of a Wood-Frame Residential Building in Quebec, Canada.”  MDPI 10.