OFFSITE INSIGHT: SIMON MCCARTHY

What first sparked your interest in offsite construction?
My first modular project was a four-storey apartment building that was designed in Melbourne in collaboration with the Architect and fabricator. The fabrication was done in China by an Australian company who leased a factory on the outskirts of Beijing. Over the following five years I have designed modular structures from relocatable luxury accommodation units to concrete prison cells, to the first three storey permanent modular school building in Victoria.

What’s the strategy behind your new position at Sensum Engineering and how might this kind of role might become more common in the offsite space?
The building industry in general has done little to invest in R&D until recently (refer to government grants such as Building 4.0 CRC and collaboration of new building technology by local industry partners). The result is that the productivity increase due to improved building practices over the past 20 years has been minimal. The capacity of the building industry to adopt modular / prefabricated construction practices in Australia needs to increase soon, for us to keep up with demand for new housing, for us to develop experience in this form of construction and for us to remain competitive against internationally recognised builders who are beginning to enter the market with high quality solutions.

My role leading the newly established engineering division at Sensum is to contribute to the design phase of projects at a very early stage and to demonstrate how structural framing can be refined to produce an efficient, non-complex solution on many new building projects. This is particularly relevant in accommodation type projects such as: apartments, aged care, hotels, hospitals, schools, student accommodation, affordable housing or corrections facilities.

“My role leading the newly established engineering division at Sensum is to contribute to the design phase of projects at a very early stage and to demonstrate how structural framing can be refined to produce an efficient, non-complex solution on many new building projects. This is particularly relevant in accommodation type projects such as: apartments, aged care, hotels, hospitals, schools, student accommodation, affordable housing or corrections facilities.” Simon McCarthy, Principal Structural Engineer, Sensum Engineering.

What are some granular examples of how your expertise can assist?
The majority of modular projects in Australia are single or double storey. This doesn’t need to be the case! I’ve worked on a number of multi-storey projects; in fact, the more storeys, the more efficient a modular structure is. A prime example is correctional facilities. Most prison cell buildings in Australia are double storey. The design I developed using a sixsided concrete shell can allow a site to meet the current requirements for two storeys, but have additional floors added up to a maximum of six storeys at a later date and without the need for any additional bracing. This would save a lot of valuable land space and have provision for special needs such as aged care or disabled inmates being allocated to their own floors.

Are there any solutions or methods that you particularly enjoy working with? Why?
I find steel framing is the most adaptive material to modular projects due to the availability of suitable member sizes, trades and connection types, as well as its ability to withstand various load scenarios. I’m also a big fan of volumetric construction as opposed to flat-pack, so most of the construction can be controlled in a factory environment for consistent dry environment, production line assembly and high quality outcome. This approach also provides more predictable costs, delivery times and reduction of waste. Light gauge steel framing methods are being developed for use on projects up to five or six floors high in other countries that would provide significant savings on transfer floors over basements, or footing design in areas with difficult soil conditions. Concrete modules are also overlooked in Australia due to the cost of craneage, but they are used successfully and extensively in many countries. We have access to dry connection details that suit earthquake design requirements without the need for dowels and grout for when the next appropriate project becomes available.

Do you interface directly with builders in your role?
Absolutely! I mentor junior engineers to understand that the development of a modular building is a two-step process: construct the building first as a digital model, then again as the final physical model. It is instrumental to have a builder involved in both stages to identify construction issues during the design stage (treated as a trial run), so that provision for lifting, transport and assembly of modules during construction phase has been developed before a building permit has been applied for.

What would be your advice to builders considering engaging with offsite?
Join a team with experience in offsite construction, rather than try and learn it from scratch. Otherwise, some of the benefits of saving time and costs will be lost due to errors. Sensum can provide the experience in both engineering design and project management of developing a building using modern methods of construction. We can refer you to experienced architects, service engineers, modular fabricators and head contractors who can join us as part of a team to assist in this process.

What are your biggest offsite bugbears?
There are two that spring to mind. The first is funding drying up due to poor financial advice. Anyone intending on using offsite construction needs to be transparent of those intentions with their funding provider.

The second is a key misunderstanding that comes up regularly. The design phase for modular projects requires time, effort and coordination amongst architects, engineers and builders before all three disciplines can agree on the optimal design solution.So, developers who believe that modular is repetition and that repetition means less work and less fees, have a gross misunderstanding of the design process. A more accurate understanding is that the increased costs associated with increased design time will be returned with a building that provides a quicker rate of return on investment with reduced delays and less maintenance.

Any final words?
Modular / offsite construction is not the golden ticket for resolving many issues in the building industry. However, early advice from an experienced design team will steer the development of a building project in the right direction. ■