Just The JOSB
Modern methods of construction | July 2007
FROM: LABM July/August 2007
'Industry campaign set to cause a stir at interbuild.'
Claire Clutten travels to Inverness to gain a better understanding of OSB panel manufacture — from the forest to factory finished stage — and uncovers what it has to offer sustainable building projects.
Now in its second year, the JOSB Done campaign was established in 2006 to promote the uses and benefits of Orientated Strand Board (OSB) to the construction industry. The campaign is a partnership between OSB manufacturers Norbord and Smartply, the Wood Panel Industries Federation (WPIF) and resin supplier Huntsman. Despite OSB consumption doubling worldwide over the last 10 years and its growing popularity in the UK and Ireland, plywood is still a more widely known and sourced product. Alastair Kerr, director general of the WPIF attributes this to a general lack of awareness within the building industry: “With OSB, it’s what’s on the inside that counts. It’s therefore important for us to encourage merchants and builders alike to take another look at what OSB has to offer in terms of it being a precisionengineered panel of consistent quality that’s suitable for getting a range of jobs done. These include cladding walls and roof sheathing to I-joists and even building timber frame houses.”
Raw Deal
OSB as a building material dates back to the 1960s and is manufactured using raw timber harvested from sustainable forests across the UK and Ireland and independently certified by the Forest Stewardship Council. The forests are carefully managed, with trees selected, felled and all branches removed before the logs are cut to length and transported to the manufacturing facility. The forest site is then cleared, trees planted and the process begins afresh. Once transported to the manufacturing facility, the logs are cut into smaller lengths and the bark removed before the timber is chopped into credit card sized strands of wood. At this stage, the wood strands are blended with resin and wax as part of a carefully controlled mixing process before being laid down, layer upon layer to create a ‘mat’. Once coated with the resin mixture, the first layer of strands are carefully and evenly distributed onto a conveyor belt. The credit card sized pieces run first one direction and then in opposing directions, as second and third layers are added. By layering the strands in this way, a cross-ply effect is achieved that gives OSB its extra strength and durability. The final board is produced by pressing the three layers of the mat together under heat, resulting in a board of OSB with a smooth, consistent and defect free finish.
Mark of Quality
At Norbord, all OSB panels are marked with time and date of manufacture and include certification details to enable the products to be traced back to source. The Company works hard to ensure its manufacturing processes are as efficient as possible, from an operational and sustainable perspective. Emissions are 100% recycled via the pollution control section and any waste products produced are recycled back into the process by the outsourced recycler which converts scrap into reusable particles, whilst the yard clean up is used to fire the furnace. Just the JOSB Claire Clutten travels to Inverness to gain a better understanding of OSB panel manufacture — from the forest to factory finished stage — and uncovers what it has to offer sustainable building projects. Modern Methods of Construction Once coated with the resin mixture the first layer of strands are carefully and evenly distributed onto a conveyor belt Once coated with the resin mixture the first layer of strands are carefully and evenly distributed onto a conveyor belt OSB at the start of the manufacturing process 029.LABM_J-A07 26/6/07 11:59 am Page 29 The demand for zero carbon construction products and building solutions will only increase in years to come and it is now no longer enough simply to specify energy efficient materials. The product’s carbon footprint must also be taken into account. This is already having an impact on manufacturers’ production processes across the UK and Ireland and it is companies like Norbord and Smartply for example, who are leading the way. The raw materials both companies use are sourced from FSC certified forests local to the manufacturing facilities.
Types of OSB
There are two types of OSB – OSB2 and OSB3. The former is suitable for load bearing applications and dry conditions, whilst the latter can be used where moisture is present and in high humidity conditions, without any risk of structural change to the strength and durability of the panel. The Inverness “SterlingOSB” range from Norbord consists of panels suitable for dry and humid structural use plus Sterling Roofdek is designed specifically for roofing applications. As it meets the same performance standards as plywood, yet is more costeffective. SterlingOSB has excellent moisture tolerance and is less susceptible to the stress-related problems of plywood, such as warping and ply separation.
Timber Frame Homes
In Scotland OSB is proving to be highly compatible as a construction material for timber frame housing. The use of timber frame in housing construction is growing in popularity throughout the UK, partly due to its ability to speed up the construction process, which means a faster return on investment, as well as reduced disruption to local communities, and in many cases tidier, safer and more efficient sites. In addition to this, a typical timber frame house can be weathertight in less than five days. According to statistics from the UK Timber Frame Association, if all UK houses built since 1945 had been of timber frame construction, then over 300 million tonnes of CO2 would have been saved. Most wood products, from timber frame systems to joinery, can also help designers and developers improve their EcoHomes ratings. Tulloch Homes, based in Inverness, produces approximately 300 timber frame home kits a year. The kits feature treated OSB from Norbord, which is used to clad the external wall frames. The Company is working with social housing providers across Scotland supplying its timber frame kits to affordable housing projects. A basic timber frame bungalow kit takes only half a day to build, which considering the ever growing need to build more homes and at a quicker rate, is a huge boon to the industry. Currently over 73% of new homes in Scotland are built using timber frame, an increase of 8% from 2004, and by 2008 one in four new homes in the UK is expected to be of timber timber frame construction. Considering the fact that each timber frame home is said to save approximately four tonnes of CO2 (about the amount produced by driving 14,000 miles), this is a significant plus for the environment and will go some way to helping government get back on track with its carbon reduction commitments, with OSB playing an integral part.
To find out more about OSB and the JOSB Done 2007 campaign, visit www.josbdone.com or call the helpline on 0845 053 3277.
