Increase the pressure
When Bullock Construction specified timber frame for the first time on a housebuilding project in Coventry, the client suddenly demanded more apartments to the same deadline. TiC goes onsite to find out how Bullock coped with the extra work.
IT IS a race against time for contractors to get projects completed and handed over to their clients and often a competition between subcontractors and suppliers to get their ends of the job done faster.
Bullock Construction found itself in such a situation on a housebuilding project in Coventry, when its client, Orbit Housing Group, upped the ante and demanded more units in the same period of time. Project manager Greg Parton says the company found itself having to build 52 units instead of 29 without any leeway on the handover date.
“Although the other 23 units were apartments, instead of the three-storey houses we’re building elsewhere on the site, they’ve still put a strain on getting the project completed,” he says.
The A team
The contract has been a learning experience for Bullock as it is the first time it has used timber frame as a construction method. The majority of Bullock’s work has been in brick and block, but the company has teamed up with timber frame supplier Frame Wise on this project. Parton says he has been amazed by the speed of construction.
“Within a few weeks, the buildings appear from nowhere,” he says. “A threestorey building can get roof-high within two weeks, which would be very hard to achieve with traditional build. We aim to have the buildings weatherproof within three to four weeks, which then allows us to get other trades onsite.”
Parton says the company changed its working practices to accommodate its timber frame supplier. He said this involves preparing the site for just-in-time delivery.
“This is the first project I have had to work with timber frame,” he says, “and my experience with Frame Wise is they couldn’t have been more amicable in getting to site when they said they would. In turn, we have gone out of or way to have everything in place for them when they arrive onsite.”
Parton says Bullock’s preparations included putting in place the drainage, roads and substructure, the loading bays and erecting three sides of scaffolding. “The timber frame gets erected immediately when it arrives,” he says. “It literally gets dropped straight into place.”
Mighty and superior
Frame Wise has supplied timber frame, floating floors, compartment floors and the insulation for the project and the company has had a team onsite since July to install its side of the project. Managing director Simon Orrells says the breadth of products gives the company the advantage when it comes to planning the logistics of the job.
“It gives us more control over the product and allows us to make sure it goes in,” he says. “To a lot of clients and contractors it’s becoming very attractive, as they don’t want to go to a lot of different suppliers. They’re looking to tie up packages with suppliers.”
Orrells says offsite construction is particularly suited to multi-storey construction projects. “You can crane the panels in, which saves doing all the manual handling after they have left the factory,” he says.
Every construction project is different and the key to success on one that involves a large offsite element is for the contractor to involve its suppliers as early as possible. Contractors are not experts on every offsite construction technique on offer and need the advice of their supplier on what they can expect on a certain project.
“The biggest problem we have is that we have to develop the design and get people involved early on,” Orrells says. “Every timber frame manufacturer develops the design differently and nine out of 10 times they don’t know which offsite route or form of construction they’re going to use. The challenge can be knowing what form of construction you need for the roof or the walls.”
He adds that the gap in knowledge in the construction process often lies with the
contractors themselves. “A lot of the younger architects know that they have to change and to ask the right questions. By the time it comes onsite you have got to know the ins and outs of it.”
The system maintains strength
Early involvement can also get round one of the biggest criticisms of timber frame buildings, shrinkage and disproportionate collapse.
“It’s a matter of thinking early about the design so that people don’t wonder why they’re having to use additional strengthening structures afterwards,” says Orrells.
He says the timing of the timber frame deliveries has led the rest of the project.
“To meet the client’s targets, there was no other way it could be done, except using timber frame and it really has set the pace,” he says. “Everyone else has had to speed up to meet it. The ground workers have kept up – we have never caught them up – and it’s the same for the scaffolders. Everyone wants it to go forward and when the client tightened the programme, everyone said they would give it a go.”
Orrells adds that Bullock has used offsite construction to beat the short winter days and meet the client’s targets. “We have still got the last two blocks to go and in the shortest days,” he says. “With winter working they couldn’t have done it.”
Another beneficial aspect of using timber frame is that it has allowed Bullock to use fewer trades onsite. Orrells explains this has saved the contractor time and has also improved health and safety during the project.
“One of the details on the job is bringing in pre-plasterboarded party walls,” he says. “These minimise health and safety risks, especially in the roof spaces because a lot of the time they’re above stairwells. That’s something we’ve developed during the project to take one trade offsite.”
Installing the insulation in factory conditions and delivering it to site as part of a panel can also cut down on the total build costs. Frame Wise has struck up a partnership with materials supplier Isover for the insulation in its panels. The company used Bitrock for this project, which Orrells explains has improved the insulation by 10%.
“Rather than thinking about timber frame by itself, you should think about it as a system,” Orrells explains. “The u-values are getting lower and lower and there’s nothing worse than pricing the insulation afterwards and then noticing it’s more expensive than you originally thought.”
Land of dreams
Frame Wise has expanded over the last six years, from a firm of purely timber frame erectors to incorporate timber frame manufacture. Orrells set up a factory in mid- Wales, which currently produces panels 22 hours a day.
The company built its first seven-storey timber frame building last year in Swindon. Orrells says that Frame Wise used high tolerances to get round problems with the site’s uncompromising neighbours.
“The neighbour wouldn’t give any access and we still managed to build to within 250mm of the boundary,” he proudly explains. The company is also racing to finish eight schools before Easter, some of which have some interesting design features. “We’ve really pushed the boundaries with completely circular schools,” Orrells says.
He adds that the demand for apartments will fuel the timber frame industry. The construction method is ideal for contractors under pressure to build higher and build faster. “It’s an interesting time for timber frame because with a lot of the land starvation at the moment, it’s a lot easier to go up than to go out.”
Bullock’s Coventry project has demonstrated that timber frame also has the flexibility to respond to increased demands from clients providing the contractor gains an understanding of its supplier’s working methods.
Orrells says he is confident that he can tweak the specifications to accommodate tricky projects. “We say if it can’t be built with timber frame, then it can’t be built at all,” he says. “Clients find that quite comforting, because with dwellings getting more complicated these days timber frame gives them some flexibility.”
Whether designers are looking for lower uvalues to meet tougher building regulations or contractors are looking for a way to hand over a project more quickly, timber frame is proving a hit as a lean, very efficient method of construction.
