On-site showbiz-style incentive scheme claws back 20 weeks.
First week on site the prize was a DVD player. Music centres, colour tellies and tickets to Premiership football matches have all followed, and the big one – a £750 foreign holiday – is still to come.

For Russell Lane, project manager at Willmott Dixon's Peartree social housing site at Welwyn Garden City, the weekly prize draw is all part of an ambitious plan to squeeze into 46 weeks a site programme originally set at 66. The site is one of two trialling the company's accelerated programme initiative, a cocktail of innovations designed to raise output by compressing construction time.

A previous operative incentive scheme at White City to pay a bonus to subcontractors finishing on time foundered on distrust. "The lads didn't know if the proprietor would share it out," says Lane. This time around he's holding a weekly draw in the canteen on Friday lunchtime, preceded by as much razzmatazz as he can generate in a huge field of mud. Into the draw go all the workers present on site every day that week between 8am and 4pm.

"The big trades – bricklayers, groundworkers, floorlayers, scaffolders – really affect progress," says Lane. If they're absent because the weather forecast is poor or leave early to miss the traffic jams, he won't be able to meet Peartree's crash programme. "Predicting outputs is all very well," says Willmott Dixon's innovations director, Brendan Ritchie, "but if the brickies don't turn up, you've got nothing."

To get into the Peartree draw, trades have to work until 4pm rather than 2.30. "Timber framers are quite happy to bung it up, but it's the finishing off that's the real key and speeds up following trades," says Ritchie.

The timber framers have only just started on site, but the scheme has already changed the attitudes of bricklayers and scaffolders. "Last Friday, we needed the brickies to stay and finish off so the groundworkers could get in and do the drains for the telecoms," says Lane. "Normally sites are deserted by mid-afternoon on Friday. Not this time. Even though they didn't win the 22in colour TV, they stayed."

It's not perfect. Many trades, like plasterers, only have a few days' work on site anyway and don't qualify for the draw. And heavy downpours on a Monday will deter all but those with their hearts set on a free music centre from turning up, so bang goes the carrot for most workers that week.

Turning worms
Programme acceleration is needed because they discovered slow worms at Peartree. Kill one of the protected species and you face a £2000 fine. Capturing and relocating the 1400 snakelike legless lizards that turned out to populate the site held up construction for five months.

"If you'd been building Peartree the traditional way, you'd be up a gumtree," says Ritchie. But Lane aims to hit the original deadline by using process and material innovations to claw back the 20 weeks that the slow worms have consumed.

For example, Lane aims to set trades to work simultaneously on the same unit. Rather than the traditional sequential practice where a unit is each trade's exclusive domain until they go on to the next, Lane says the plumber will only be given half a day's headstart to set up before electricians and other trades enter the same unit, each working on a different floor.

Fast-track prefabricated materials on the site include insulated blocks from Hanson for the ground floors (which do away with the usual extra layer of insulation), and timber-framed walls and timber floor cassettes from Pace. The factory-assembled cassettes on the first floors eliminate subsequent operations. "Two men can do five units a day with a cassette system," says Lane. "I was on another site that took four men a week to do six units with joists and boards." Craned directly to their final position, the cassettes create the deck in one operation rather than several.

Initially sceptical about timber frame, Lane is now an enthusiast. "Now I've seen how solid it is," he says, giving a stud a hefty whack, "I'd defy anyone to detect the difference from brick and block by the time it's brick-clad and plasterboarded."

The accelerated programme also involves asking subcontractors and suppliers for fast-track ideas. For example, the groundworkers proposed easy-to-cut 6m-long plastic pipes rather than heavy 1.8m-long clay pipes. And the bricklayers suggested Willmott Dixon provide the forklift operator as well as the machine. "It's avoids contractors queuing up at the site hut to complain and demand their turn," says Lane. It also means supply hiccups get dealt with, rather than everyone ignoring a problem because it's not theirs.

Streamlining the services
According to Lane, services usually represent the biggest problem in building the roof and walls. Traditionally, they go in when the scaffold comes down and then become the critical path. Delays are common, with arms-length utility suppliers leaving construction companies feeling helpless.

At Peartree, the electricity mains have gone in before the timber frame, and most of the water and gas lines are already laid too. Lane's spent a lot of time cosying up to the service suppliers and agreeing timetables. It's been worth it: the first of Peartree's 94 units has gone from ground slab to roof felt and battens in eight days.

With the project turning over the expected £500,000 a month, Lane knows the work's being done and is confident about finishing on time. And with ever more site workers coming along to watch the weekly draw, he's got every chance.

Offsite buys you time

Peartree’s dependency on the offsite manufacture of timber-framed units transfers the time saved on site to the preconstruction phase. And a week of preconstruction is a lot cheaper for Willmott Dixon than a week on site. While the greater expense of preassembled elements ups the materials bill, reduced time on site raises the productivity of a construction company’s hard-to-expand band of construction managers. With offsite, a team can complete the site work faster. “We’re Willmott Dixon’s biggest expense,” says Lane, “but we’re a hard-to-come-by commodity. Prefabrication is the only way we can increase production.” Ritchie has some sympathy with construction managers uncomfortable about getting less time on site: “You get caned for missing your completion date, so project managers like some float in the site programme.” He argues, though, that offsite allows some slack to be built into the preconstruction phase instead. For Peartree, instead of a 12-week lead-in, Lane got nine months of planning. “It’s difficult at first,” he says. “You don’t know quite what you’re meant to be doing. But you soon get into it. What’s been good is I’ve had input into the programming process.” Just as importantly, prefabrication makes for more predictable delivery. “The biggest problem in construction is overruns,” says Ritchie. “They do a lot of damage to client relationships.” In social housing – and 30% of Willmott Dixon’s turnover comes from the sector – keeping the client happy is crucial. Which is why Willmott Dixon is financing the accelerated programme initiative at Peartree even though the client, Circle 33, reaps big advantages. £75 rent on each of the 94 units 20 weeks early adds up to a great deal of money. It also looks good on Circle 33’s CV, showing a commitment to modern methods of construction.

Source

Construction Manager

Postscript

Enquiry number 215 (Pace)
Enquiry number 216 (Hanson)