• Floor systems remain the bedrock of business for metal web and I-joists.
¦ The market for roof systems will continue to grow.
¦ The emphasis on improved insulation will result in more wall stud solutions.
¦ Steico and Finnforest will launch new roof systems at Ecobuild.
¦ Pasquill is developing its own roof system.

Increasing regulatory demands on thermal performance, the pressing need to mitigate fire and health and safety risks during construction and the determination to improve build speeds have all contributed to growing take up of prefabricated, timber-based floor, wall and roof systems.

Add to that the continuing drive to offsite manufacturing and the consistent build quality and precision that can be achieved in the factory environment and the trend towards panellised components would seem to be irreversible.

Within the systems, I-joists appear to hold sway over metal-web joists on cost grounds, while solid joists continue to have their champions.

“The I-joist market remains very strong and builders appreciate the competitive pricing point,” said Simon Jones, business development director of Boise Cascade Engineered Wood Products. “The vast majority of the top 50 builders continue to use I-joists of one brand or another.”

Metal-web production remains strong, however, with Wolf Systems reporting a 30% growth in sales of easi-joist in 2011 over 2010 which itself showed “dramatic improvement” over 2009 volumes.

Market adaptation

Fellow metal-web producer Gang-Nail Systems also reports continuing growth and “market adaptation”.

“Due to the implementation of the Code for Sustainable Homes (CSH) there is an ever-increasing need for services to run through the floor zone and, with speed a key element of construction, the open-web joist is certainly able to deliver,” said Jason Ruddle, sales and business development director.

Floor systems remain the bedrock of business for both product types, accounting for as much as 80% of Donaldson Timber Engineering’s sales of I-joists and Posi-joists, said managing director Jonathan Fellingham.

And, according to Andy Moore, director of Steico UK, smaller builders and developers are beginning to look at floor systems rather than their component parts.

Demand for wall and roof systems is also picking up. “The market [for roof systems] will continue to grow,” said Stuart McKill, Pasquill managing director. “If you’re a housebuilder and you’ve got to meet increasingly high standards of airtightness and better U-values, having guys stick bits of insulation into the corners of rafters, then test it and find it doesn’t meet regulations isn’t a great solution.

“I also think that usable space in the attic – not necessarily room-in-the-roof – is becoming a more modern day requirement.”

“Although it represents a smaller part of our business at present than the supply of JJI-joist-based floor and roof solutions, specification of JJI-joists for wall stud solutions is growing,” said Mark Tilston, business development manager for James Jones & Sons Timber Systems Division. “And the anticipated requirement of Part L in 2013 will further emphasise the need for greater insulation within the building envelope, increasing the use of JJI-joist wall stud solutions.”

Product development

Manufacturers are keeping ahead of the Building Regulations with ongoing product development and improved technical guidance.

For example, ITW Industry, which developed the SpaceStud wall system in the UK, has produced a technical guide detailing various wall make-ups and connections, and has completed a 3D thermal modelling of SpaceStud. “This gives the actual thermal bridge for the stud,” said Tim Widdershoven, ITW’s marketing manager. “Clients give us their preferred insulation and wall thickness and we provide the calculated U-value.”

Wolf Systems is conducting research with the Trussed Rafter Association into the use of finger-jointed timber in metal-web joists and is also testing the structural and thermal performance of its easi-joist in a timber frame wall panel. “We’ve also undertaken testing for a new Robust Detail for easi-joist used in timber frame construction which would allow up to CSH level 3 credits to be claimed, due to the outstanding sound insulation results,” said Karl Foster, Wolf’s sales and marketing director.

Smartroof, the panellised roof system Wolf developed with Wyckham Blackwell, has also seen some developments, both in specification and operationally, with sales of the system being centralised through smartroof Ltd.

Supply chain changes

The way the product is supplied to the market has also changed, said Mr Foster. While traditionally smartroof was a supply and fit product, more housebuilders are simplifying their supply chains by using it on a supply-only basis, using their own contractors to install it.

“Smartroof’s specification has changed over the last few years,” he added. “It was re-engineered to meet the demands of a more competitive market – for example, we replaced the Bitrock top closer with a simpler, less expensive breathable membrane. The panel still performs in exactly the same way but is now more cost-effective and competitive.”

James Jones is also finding the market “all spin aside, very good” for its Intelliroof product, which it says is now one of the market leaders. “Customers and developers can see the benefits over traditional trussed rafters and nearly everyone is looking for a panellised solution,” said Mark Tilston.

He added that the product’s structural capability and thermal performance are always being improved as it is engineered to meet customer requirements. And James Jones is launching fire and preservative treatment in line with NHBC requirements for walls and working with the UK Timber Frame Association (UKTFA) on separating distances.

Fire and acoustic performance

Steico is also testing a new coated product for wall studs, as per NHBC requirements and working with the UKTFA on the fire mitigation issue and says this will greatly increase the market. It is also working towards meeting the new Scottish Building Regulation targets for acoustic performance.

Along with tweaks and improvements to existing systems, new products have been developed and are either just on the market or about to be launched at Ecobuild (March 20-22).

There’s a new crop of roof systems to look out for. For example, last year Boise Cascade launched HI-PIRform, a roof panel system combining BCI Joists with PIR foam insulation. “It’s attracting interest as it ticks so many boxes and we are ambitious for increased sales in 2012,” said Simon Jones.

Meanwhile, ITW Industry has developed SpaceRafter. Initially developed for major housebuilders, early this year the system is being used in the construction of the St Mellion Travel and Tourism Academy.

“It’s manufactured off site using timber top and bottom chords with SpaceJoist metal webs pressed in between,” said Tim Widdershoven. “Rigid, blown or quilt insulation can be fitted inside SpaceRafter voids. For faster installation SpaceRafter can be built into roof cassettes that are craned into position and we are in the process of developing a new ridge and eaves hinge to eliminate the ridge beams, saving time and money on site.”

New hinged system

Gang-Nail has also developed a hinged system that can work with any engineered component, be it metal-web or I-joist, and with solid wood.

It was showcased at its development stage at Timber Expo last year where it was warmly received and has since been modified, taking feedback into account. “We hope to launch the product officially later this year once we have gained the appropriate accreditations and independent test results,” said Jason Ruddle.

“With industry conditions as they are, any area where value can be added – evolving and expanding a room-in-the-roof, for example – is of great benefit and is sure to be a winner,” he added. “We just need to make sure it works in the correct manner and is simple and effective enough to manufacture and construct on site.”

Ecobuild will be the launch pad for another hinged roof system, this time from Steico.

“Our new Ecological hinged roof system uses Steicojoists and our insulation products,” said Andy Moore. “It offers architects and developers a fast, cost-effective and simple room-in-the-roof option for new build projects.” Other developments will follow, he said.

Finnforest is also set to launch a roof system – FinnRoof – at Ecobuild. The principle is the same as other panellised roof systems on the market although, instead of running from gable to gable as smartroof does, it runs from ridge to eaves.

Pasquill supplies smartroof, Intelliroof and MiTek Industries’ X-Rafter roof system, which was launched at Ecobuild last year. It already has experience of developing room-in-the-roof solutions, having worked with a major housebuilder a couple of years ago to develop SafeSpan, a timber roof truss construction incorporating spandrel wall panels and glulam beams with top hat trusses.

That work has been recognised by inclusion in the Construction Product Innovation Guide and Pasquill is now working on its own panellised roof system.

“Within [parent company] Saint-Gobain we have significant opportunities through our inter-company and inter-supplier relationships,” said Stuart McKill, citing thermal and acoustic insulation specialist Isover and plasterboard and acoustic ceiling products specialist British Gypsum as examples of the former.

“Developing a Pasquill system is important to us and will also help leverage the overall strength and market position of Saint-Gobain.”