Off-site manufacturing

Off-site construction is usually sold as the answer to all the industry's problems. The promise is better quality and faster project delivery. Sites are also safer, partly because there are fewer people around to get injured. But for the teams delivering these projects, it can be a different matter. The architect has to design not only the basic building, but also how it relates to the manufacturing process. Once that process starts, it is hard to make changes. This means that members of the team such as the M&E engineer have to be involved far earlier in the process than is usual. For this off-site edition of Specifier we have brought together four construction professionals experienced in delivering off-site solutions to see what they think.

Bill Ireland & Dave Turnball (left to right)

c

When would you opt for an off-site solution?

Ben Chamberlain It starts with an informed client who can see the opportunities, but it also depends on the type of building that's being built. Off-site manufacture suits a fairly repetitive design such as a prison or student accommodation.

Bill Ireland From an M&E perspective, off-site solutions are very useful for plant rooms, because they are incredibly labour intensive. If you can shift that labour away from site, particularly to an area of the country where labour is cheaper, you can save money. The other thing is, if a project is running late the commissioning of services is always squeezed, and this is the most important part of the M&E installation. Having modular plant is a huge advantage.

Dave Turnball The key is a client who has a repeat business model. We couldn't operate if we were tendering different solutions each time to different clients. We do the specification reasonably well on the first project, but it is a learning curve and it's only on the subsequent projects you get the specification absolutely right and you can derive the benefits.

Phil Green But if you see off-site merely in terms of repeatability, there is a risk you remove yourself from the bespoke market. The answer is to be more dynamic in the way you approach off-site construction. We need teams that are working for bespoke projects.

What are the main problems you face using off-site manufacture?

Chamberlain The trouble is that everything has to be designed upfront, which is a problem as architects do need time to develop ideas. Once the manufacture button is pressed it's difficult to change anything. It's not just the building plan, it's also how you clad the building. It does mean there is little to do afterwards, though.

Turnball The one thing I hate is a client that changes its mind and says: "Can I have a modular option on this design and can I have it in a week?" It's bound to end up as more expensive as it hasn't been designed as a modular scheme from the beginning.

Is it difficult to convince clients that modular construction is cost effective?

Turnball We need to demonstrate at concept stage that there is a commercial imperative. With an educated client you will get that buy-in, which is the only way it can work.

Green The co-ordination of services is key in terms of costs. Traditionally, you get a drawing showing the route of all the services so you spend three months working out how these will fit into the building. If we are involved early on we can design fully fitted service modules. The services have to be modelled differently, there's no cost difference but you do remove waste.

Ireland Off-site teams have to work together early on. With traditional construction, services design has been right down the line. But this is going to have to change as the 2006 version of Part L means the M&E engineer has to be involved from day one. This is going to drive integrated teams and it is a shift that the whole industry is going to have to take note.

Speaking of integrated teams, how important is the relationship between designer and specialist contractor?

Chamberlain It's imperative to have the off-site contractor on board, as they understand the limitations. We develop a plan for the scheme, which is then reviewed with the rest of the team. The off-site manufacturer will advise on which bits will work and which bits won't.

Turnball The concept stage is led by the architect with input from others but we take responsibility at the detail design stage, and do a lot of the detailed design. If the team isn't integrated it means you have two design processes going on at the same time and the client is paying for that.

Green Integrated teams are the only way to get off-site manufacture to move forward as it will never work if the team is fragmented. There should be no need for the specialist to employ, say, a second engineer. The whole team should be working together to come up with the right solution.

Name one thing that would make off-site construction more efficient.

Ireland Having one IT base, so there is no duplication in the design process. Traditionally the M&E contractor takes our section drawings and produces its own fabrication drawings. With a single IT base you would do it just once by working together on one drawing.

Green A lot of elements could easily be standardised. For example, in a hotel, every riser is different, but this could be standardised. We do a domestic energy centre; these are the same every time and you just plug it in. People now ask why it has taken to get so long to this stage.