Conversations with creative thinkers.
Lee Kay Lian, Warren Liu, Darlene Smyth, Tang Kok Thye, Samuel Vedanaigam, Kengo Kuma, Realrich Sjarief, Du Juan
Should we build our future homes in factories, like cars and planes? What is the current state of prefabricated construction in Singapore? We asked five pioneers who have been exploring prefab methods for residential projects in Singapore and around the region.
“[T]he use of PPVC for landed residential is still practically non-existent here. People have yet to subscribe to the idea.”
Warren Liu
Asih Jenie (AJ) Let's talk about prefab construction in Singapore’s residential sector. How advanced are we, and what's the take up rate? Tang Kok Thye (TKT) Prefabricated Prefinished Volumetric Construction, or PPVC, is one of the strategies in Singapore’s Design for Manufacturing and Assembly (DfMA) productivity roadmap. Instead of building on site, you’re building in a factory – like manufacturing a car. Right now, the government is the main initiator for PPVC through government land sales that mandate the use of PPVC for certain sites to drive the volume.
We started experimenting with modular housing in 2011 with six prototyped units of studio apartments using drywall and steel. Then, in 2013, City Developments Limited (CDL) invited a few architects to pitch for the first PPVC residential development in Singapore. ADDP Architects got the job. That was the 12-storey Brownstone Executive Condominium in Sembawang, and it has become a viable example of PPVC.
Down the road, I think there will be definitely be increase in PPVC demand. PPVC can be applied beyond the residential sector, but in Singapore the residential sector drives the demand because of the huge volume.
Warren Liu (WL) But unfortunately the use of PPVC for landed residential is still practically non-existent here. People have yet to subscribe to the idea. That’s why we are pushing a ground-up initiative to introduce prefab to the landed housing market. It’s a challenge to change the mind set.
We initiated the Monomer House 1 project because we saw the benefits of modular volumetric housing. And it’s great that the National Design Centre allowed us to make this into an exhibition through which we’ve been able to promote the technology. We’ve had a lot of enquiries and also we’ve started residential projects using modular panel construction made with light-gauge steel.
Lee Kay Lian (LKL) Another challenge is the capability of the local contractors who are still in the early stages of technology adoption. They haven't had the opportunity to put the innovation into practice because demand for such construction methods is still low. This influences the confidence levels of the designers and consultants who advocate for this way of building.
Sam and I started Pod Structures because we saw the pressing need to integrate and cross-fertilise different trades. I’m an architect by training and he’s a builder. Sam has a solution that has already been in the market for a long time and I saw the opportunity to create an architectural product that can open up more opportunities for building types that otherwise don't lend themselves well to prefab. Samuel Vedanaigam (SV) Prefab and modular construction is not new. Eighteen years ago I installed a modular large-span structure in Singapore for D’Marquee Downtown East in Pasir Ris , before it became widely advocated. Going forward from there, I wanted to apply the same idea for smaller structures, so I developed and patented the Tubelar System. It's a lightweight, modular knockdown system that can be installed on any terrain, made with aluminium and composite materials that could easily be deployed by a small team of installers under supervision. This system was used mostly for pop-up and events, until Kay reached out to me because he was searching for a builder to implement a disaster relief program in Bohol, Philippines, following the 2013 earthquake. From there we started exploring other applications.
LKL We're looking at prefab construction using a simple assembly approach. The components are broken down to smaller pieces and can be flat-packed, making the construction more agile because you can move components to different places and target difficult-toaccess sites for landed residential and asset enhancement projects.
The automotive and aerospace industries are building watertight and soundproof structures that are hurtling through space at high speeds. So why is building construction so slow to progress? Construction has never been thought of in terms of ‘product’. It’s always considered a fixed asset – a building must come with a piece of land. And because of that archaic way of thinking, construction hasn't really transformed over the last 300 years.
Meanwhile, we can test out things that are made in factories. There’s no prototyping in building because the prototype is the product. But let’s say we’re prototyping a residential module; test it until it really works well, then mass produce it and bring it to site. With that approach, I think we can get somewhere closer to those other industries’ level of innovation.
AJ How does Singapore’s performance in terms of prefab compare to other countries?
TKT At this moment, Singapore is the most advanced country in Southeast Asia in terms of adaptation. Different countries have different needs and considerations. Just like in Australia and Europe, labour cost is increasing in Singapore so prefab is a necessity. Labour is still comparatively cheap in the rest of the region. As long as there’s cheap labour, people won’t take this direction.
People fly from Hong Kong and China to study prefab here because it makes sense for them. Hong Kong with its density and China with its massive scale – we might say a 1,000-unit project is big, but for them it might only be phase 1A.
And for China, since they have space, the factory can be built closer to the site, which reduces the logistics costs. Our modules are produced in Johor Bahru and transported to Tuas or Woodlands before being delivered to the site. In China it is possible for them to build the factory next to the site, since they have the room.
Darlene Smyth (DS) In Canada, prefab houses are the norm. Lowrise brick construction is reserved for government and institutional buildings, via tender. I would say that most people live in prefab houses. To have an architect design and construct a house is considered special and will be very expensive.
Most people select their houses from a catalogue. Then you build your foundation and plumbing and the house arrives on flatbed trucks in two sections, like a dollhouse, then they put it together on site. It’s made with timber and they’ve also been using light gauge steel for over 30 years. LKL What makes your clients receptive to prefab houses, Warren and Darlene?
WL Most of them subscribe to the idea because of the principle.
They believe in being sustainable, and by building with prefab, your resources are better managed, you cut down the energy consumption, and you create significantly less noise and mess with the scaffolding.
TKT Sustainability is one of the driving forces that we’ve noticed as well. People are demanding sustainable design. But if they just looked at dollars and cents, nobody would do it. They’d go for the cheapest option.
LKL We do recognize that cost needs to be considered when implementing something new.
DS In one of our projects, the client did save money because there was no need for piling due to the weight [of the prefab solution]. Had we done conventional construction, they would have needed piling. That alone can save hundreds of thousand dollars.
TKT When there's enough demand, the cost will go down. We've seen a parallel in green buildings. Fifteen years ago, the cost for platinum Green Mark was almost ten per cent of the project, but now it’s not more than five per cent, with many projects in the two to four per cent range. It’s the same for modular housing. In early days it would cost 15 to 20 per cent more, today it’s fifteen per cent or even less with about eight per cent for private residential developments adopting concrete PPVC. PPVC only started five years ago and I can foresee in ten years it will be a level playing field.
SV I think there can be more awareness about the advantages of prefab construction and how it can benefit home owners.
TKT The people who most need convincing are the ones doing the job. The contractor will say, “This is how we do things, and now you want us to do something different?” They increase the cost even though you are actually trying to reduce it. You have to break down the cost savings; “You produce this in a factory – that’s eight hours a day, no overtime, you can finish in eight days instead of ten, and you don’t
have to travel to different sites for different projects.”
DS The most common question we get from visitors to the
Monomer prototype is about the cost. The second is about the speed of construction.
WL There is an actual price tag to Monomer House 1, which is SGD 98,000 inclusive of GST for two modules, about 450 square feet with 380 square feet of built space.
TKT So that's about SGD 260 per square foot. Conventional modular cost will be about SGD 300 to 350.
DS That's completely finished with green walls, fit out, modular furniture and solar panels. People were also curious about whether the modules can be shipped to their properties in other countries. The answer is yes. Monomer House 1 was designed to be shippable. The size of it was based on what can fit on a flatbed truck. The lightweight steel makes it one-tenth the weight of concrete structure, so it will save costs and not add too much extra load if a module is added to an existing structure.
WL The whole idea is to generate a kit of parts, like a vehicle. We will have basic models, which you can customise. We will make it intuitive for any designer or layperson to look at the parts and figure out how to use them.
LKL Our MOVIT modular home prototype is also a self-initiated case study. We can pack 72 square metres of space inside a 20-foot shipping container in one of our disaster-relief projects – that’s when we decided that we wanted to adopt the quick-assembly method for the housing product as well.
When your family grows, you can add a module, change a module or the internal lay out, or just pack it up in a container and move it to another site. These are the objectives – to make prefab nimble. The concept was inspired by the tropical vernacular kampung house.
It’s called MOVIT because you can really move it. It can also be applied to market sectors like co-working, hospitality and F&B/ Retail pop-ups. We could build structures on rooftops and under viaducts for example. It has the potential to unlock sites. We’ve activated vacant residual spaces once considered unusable just because traditional methods made it impossible to build a concrete and steel structures there, converting these sites into real estate with value.
SV We are working to integrate as many trades as we can, and have looked into various materials and components, including the testing requirements for target overseas markets.
TKT The government thinks very fast. The first few buildings using PPVC were 10 to 15 storeys. We are completing the tallest PPVC in Singapore at 40 storeys. There’s one project we’re doing with UOL that would be the next tallest PPVC building in the world – 56 storeys. We’ve become more adventurous now that we’ve got to know the system. We push out sky gardens, change up the facade – we’ve got a toolbox full of Lego-like modules we can confidently pick and choose from.
Now we're looking into using timber instead of steel. It’s lighter and easy to work with. We will start at the small scale, test it and see if we can roll it out for bigger projects. We’ve built a team of architects who are very competent in this area because they have been involved since the beginning. We hope to share this with more architects, builders and engineers in the future.
This system should not be proprietary. It should be something that is usable by every one of us to set the whole thing in the same direction and improve the productivity as a whole.
a-dlab.com addp.sg podstructures.com
“Construction has never been thought of in terms of ‘product’. It’s always considered a fixed asset – a building must come with a piece of land. And because of that archaic way of thinking, construction hasn’t really transformed over the last 300 years.”
Lee Kay Lian