As a registered commercial and domestic builder that has transitioned to a volumetric modular manufacturer, I believe that prefabrication offsite is the best solution to quality and speed, the more you can advance a modular product within the factory environment the greater the advantages.
In my professional opinion volumetric modules is the most evolved solution on offer, if designed correctly.
Design for Manufacture and Assembly – Disassembly (DfMA-D) is an essential element to a successful modular construction project.
There are a number of key elements to DfMA-D that need to be considered.
The first step is to engage an experienced modular manufacturer early in the design stage and using design consultants that are experienced in Modern Methods of Construction (MMC). The design documentation has to reflect the way the modules will be manufactured. Each manufacturer has their own building system; therefore, it is preferred that the design is tailored for their system, making it important to engage your preferred manufacturer early.
This avoids the costly exercise of redesigning more than once which we see occurring way too often. Modular manufacturers will have the most up to date information feeding back from the field that is growing and learning new faster and better ways to manufacture every project.
Minimize the part count
Reduce the total number of modules as much as possible, this is done by designing your project in larger module sizes rather than smaller modules.
This optimises the structural design, reduces the number of crane lifts, and reduces the transport costs. It also equates to a lot less work onsite as there are less connections to be made.
Designing 2 apartments within one long module with a centre hallway is a great example.
Standardise parts
When modules are designed to a standard size as much as practicable for a project, the economies of scale are far greater. Engineering, material ordering, trade experience and repetition in fabrication are all optimised when the modules are standard sizes throughout the project. The key to modular construction is repetition, and this is where you will see the greatest savings.
Design for efficient joining
Less modules equates to less joins onsite, resulting in less labour onsite, faster construction time and ultimately the project will be as close as possible to completion before leaving the factory.
The goal is to have the project past 90% completion before leaving the factory, in some cases this will mean apartments will be even fully furnished internally.
Joining modules against walls rather than through kitchens and wet areas, basic principles like this ensure those labour intensive and high-cost areas are completed in the factory in a controlled environment.
Module orientation (vertically and horizontally)
Module orientations in design ensure the modules travel through the factory in line and at a faster pace, and ensure faster assembly onsite when craning them into position. When designs go vertically with multiple floor levels and the modules can be stacked in line with direct load paths this also feeds into all of the above benefits and ensures better pathways for services and alike.
Transport and overall design parameters
Module design parameters are governed by the overall dimensions allowed to be transported by road.
In short (with pilot cars and a specialized trailer) a module can be up to 20m long, 4.5m high, 6m wide, and with a weight limit of up to 40 ton per module. These limitations do not have to affect the overall size of the project, as modules can be connected together. Open buildings like cafes and alike can be 2 x 6m modules next to each other achieving 12m spans.
By optimizing size, quantity, efficient joining, orientation and transport parameters, modular construction projects will be built quicker and cheaper.
Disassembly is an important aspect of the construction industry.
The key is to contribute towards net zero emission and become smarter with material selection, reducing waste and recycle as much material as possible. These principles have to be adopted, not only during the construction phase but throughout the entire building’s life cycle.
If the average building has a life cycle of 50 years, DfMA-D is planning for the future, and designing in a way that the building can be disassembled and broken down.
The key aspects to this are reversible and accessible module connection.
DfMA-D can be best achieved by certifying a built-in lifting system, allowing easy access for cranes to connect onto during install and dismantle. Design documentation, and operation & maintenance manuals including disassembly instruction plans should all be included in part of the handover pack to the end user.
We don’t know what the future holds, but designing buildings in this way offers greater flexibility.
When designing your modular project DfMA-D optimisation is only one consideration, design flare, aesthetic appeal, fit for purpose and final use are also important factors. Balancing the project budget and dismissing wrong perceptions of modular construction are all factors the right designer and manufacturer will account for during the design phase. If planned and designed correctly every modular construction project should enhance the construction industry, and build trust and reputation for consumers.
Industrialised modular construction is the way of the future.
If you are considering modular construction for your next project, always consider engaging a modular manufacturer early to get the right advice from the start and optimising DfMA-D.
