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Ticking All the Right Boxes
2009-09-01
Source - Building news September 2009
Within the current economic climate, it is clear that cost is going to remain a driving factor when it comes to the specification of materials within construction projects. However, with the industry moving towards greener alternatives, timber is coming into its own, with OSB leading the way as the panel of choice across all areas of the industry in terms of cost, performance and environmental credentials.
Just ask Darren Jarman, Director of Lowfield Timber Frames. Involved in various innovative building projects across the UK, many of which hugely benefit the communities they are a part of, Lowfield Timber Frames have now successfully achieved their chain of custody for both FSC and PEFC, which has been a big achievement for the Powys based manufacturer.
“Since we established the timber frame wing of the business in 2001 at our Marton site, Lowfield Timber Frames has undertaken a wide range of projects for housing associations where the key focus has to be environmental compliancy. Care homes, nursing homes and social housing all require us to meet the standards set by the Government for the Code for Sustainable Homes, and it has always been important for us to show we have the appropriate certifications so for us, going for the chain of custody was the next logical and progressive step.”
Used as the external skin for their timber frame constructions 99% of the time, OSB is chosen for its structural integrity and consistent performance. “Generally, this decision comes from our structural engineers. All of our frames are structurally engineered to high set standards and OSB is the best product solution for what we aim to achieve.
“The racking resistance provided by OSB on the outside of the panels is strong, but aside from this, around 70% of the projects we do now involve the engineered I-beam which features OSB as the structural web material. Also, more and more clients are asking for roof sarking made from OSB and some even insist that OSB is always used for the roofing.”
So is it a case that the client is driving the demand for OSB, or is it compliancy with sustainability standards that is increasing the market for this strong board?
“For us, it’s not so much that our clients are pushing us to use more OSB – as an engineered product, we choose to utilise OSB for all the benefits it has to offer.
“From an environmental point of view, we certainly like OSB because it has all the correct certificates in place. It is FSC rated whilst many of the plywoods available on the market are not and even if they do have this accreditation, they tend to be three times the cost when compared to OSB and do not perform to the same standard.”
OSB manufactured in the UK and Ireland is always sourced from locally managed forests that are independently certified to Forest Stewardship Council (FSC) criteria. This ensures that the raw material travels a shorter distance to the manufacturing mill, whilst making it possible for manufacturers in the UK and Ireland to trace each and every board of FSC certified OSB they produce to the exact forest it came from and to mark the panels with other relevant technical data. Unfortunately, the same cannot be said for unsustainable plywood manufactured, for instance, in China and South America with raw materials originating from threatened rainforests, which doesn’t have the correct quality and environmental credentials that OSB has.
Guaranteed to Perform
“I must admit in the early days, we did use plywood,” continues Darren, “but I remember there being an awful lot of problems with it delaminating, which you just cannot tolerate when the inherent strength of timber frame comes from the racking strength of the sheathing material. It is well known that with OSB you don’t encounter delamination issues plus you won’t get any knotholes or any core voids in the boards. So not only are you getting a board that doesn’t have any of the concerns associated with plywood, OSB is also the cheaper option, which is why it has been an obvious material of choice and why Lowfield Timber Frames hasn’t used plywood within timber frame constructions for over ten years.
“Our number one goal is to ensure our buildings stand the test of time so the structural integrity is key. All of the pitfalls you can get with plywood you don’t get with OSB and from a manufacturing point of view, we want a smooth process and OSB has dimensional accuracy, it is easy to rout, cut and to work with, plus you can nail much closer to the edge than you can with ply whilst still maintaining the strength of the board. The working performances are much better which is what drove us down the OSB route in the first place and now with its competitive price point, the emphasis on proving your chain of custody of materials and being compliant with the Code for Sustainable Homes, we think OSB is really coming into its own now.”
OSB – The panel of choice
For some, this shift change has been a long time coming as despite being available in the UK and Ireland for over 20 years, a general lack of awareness of OSB’s properties and varied applications has meant that the industry has sometimes been slow to pick up on the possibilities.
The JOSB Done initiative, supported by leading manufacturers SmartPly and Norbord, resin supplier Huntsman and the Wood Panel Industries Federation, aims of spreading the word about the uses and benefits of FSC certified OSB over non-compliant plywood, and over the four year duration of the campaign, has witnessed changes in attitude across all sectors of the building industry.
“The challenge has been to meet common misconceptions head on and over time, change long-established purchasing and specifying habits.” says Alastair Kerr, Director General of the Wood Panel Industries Federation. “However, after four years of hard work, interest in OSB is at an all time high especially as builders are realising its viability within the current climate, based on comparative cost and guaranteed performance on the job.”
For Lowfield Timber Frames, it is a combination of the two that makes OSB their panel of choice. “We do have to ensure that we supply our clients with a kit that comes within their budget,” says Darren, “but more importantly we also need to make sure it is structurally sound and meets all the environmental standards they are looking for. When you bring all these elements together, OSB comes out on top every time.”
The opportunities for OSB look bright, with Lowfield Timber Frames branching out into the manufacture of SIPS. Utilising OSB boards either side of an insulated core, this is proving to be a key market for growth where a much higher specification is required.
Darren concludes: “The Code for Sustainable Homes has set a road map for where the construction industry needs to be, with standards increasing annually. As everyone strives to get to meet these standards, it seems to me that OSB will only be used more and more.”
Pix Darren Jarman - Director Lowfield Timber Frames
