黑洞社区

鈥淭he main difference between traditional construction and off-site construction is that the latter is more about exploring things. You have to spend a lot of time behind the scenes investigating what you鈥檙e actually going to build and how it will fit together. Sometimes we come up with things we鈥檝e never done before at all. We look at magazines and the internet to get as much information as possible 鈥� it helps you get an idea of what you鈥檙e talking about with manufacturers. Off-site methods bring you out of your own safety zone. Without a background in traditional construction I鈥檇 be lost, because there are some practical issues (cavities, strap, etc) you鈥檒l never get away from. It makes it easier to accept new methods, but do we gain real time?

In practice, you spend the same amount of time creating the drawings and foundations. But then it鈥檚 rocket speed. It goes up so fast that you see the buildings come up after three weeks, dried out with the weather. Generally speaking, when you programme for a traditional site it goes very much the way you think it should with time, because there are very few ways to reduce the timescale. But with off-site construction we know that we can complete work considerably faster.

At Cambourne we built the first three sites, and the first seven units of the fourth, using traditional construction. This is the biggest job, with 71 units. But the client鈥檚 challenged funding meant we had to flip to off-site methods to reduce the timescale. We worked with our off-site construction consultant Mtech Group to investigate and evaluate the best off-site techniques for the project. We introduced timber framed units and light gauged steel frame. Off-site methods speeded things up tremendously and were more controlled. We completed the site in 76 weeks instead of 90-something, as in the original contract.

But off-site construction is not without its difficulties either. It鈥檚 not always that easy to find people who can produce the quantity that you want in the time available. The big problem is lead times for manufacturers and delivery. You don鈥檛 have these issues with traditional construction because you have a bit more time to look at things once the ground work has started. With off-site construction you need to get it right at the beginning.

In practice, you spend the same amount of time creating
the drawings and foundations. But then it鈥檚 rocket speed

It makes no difference to the guys on site though. On a standard day on the whole scheme you probably end up with the same number of people as an average, although you do have very intense construction periods when you have an awful lot of trades on site. Since we moved to off-site methods at Cambourne we counted more than 140 people on site one day 鈥� most of them from the installing and finishing trades. But once they鈥檝e done their job, numbers drop dramatically. On the busiest day then we would have 40 to 50 people on site. In traditional construction everybody follows each other in a circle but in off-site construction everyone is there at once.

And this is one of the most challenging aspects of off-site construction. There is a lot more to see and check very quickly because things get covered up so fast. The site managers have evolved to suit that move. They have to get closer together with everyone else involved and demonstrate better communication skills, because a lot more co-ordination is required than before. That鈥檚 why the number of supervision managers has increased. On a traditional building site I鈥檇 be quite happy to go with three people with me, whereas we need at least five for an off-site project. But you don鈥檛 senior site or . Assistant level people can look at sections of the work and report. This means trainees and year out students can see every operation. On a traditional build they could only see one section of the work.

I said that off-site construction is more about exploring things. It鈥檚 true. With traditional construction you know what you鈥檙e going to get. But with these new systems they throw in strange bits and pieces you wouldn鈥檛 expect. It鈥檚 like a jigsaw. When it comes off it鈥檚 a real buzz.鈥�