Panel progression

// the building envelope

HA Magazine’s Bruce Meechan discovers how the advanced panel products available from a UK and Irish manufacturer are helping advance offsite system performance. 

There was a time when the construction industry relied on the ubiquitous three-quarter inch sheets of plywood for everything from site hoardings to shuttering, flooring and sheathing the early timber frame assemblies.  Now, however, as the comprehensive collection of panels available under the SmartPly brand demonstrates, such products have advanced to achieve much broader technical and performance standards. In fact panel products such as SmartPly VapAirTight and SmartPly OSB3 now lead the field for both prefabrication and in hybrid methods of building.

SmartPly VapAirTight has been developed through exhaustive testing both in the Coillte Group’s Irish plant and at a leading European university; and then proven in practice on a cutting edge, architect led, low energy project in Ireland.

Significantly, independent testing by a German institution revealed that OSB from a variety of sources, was not as airtight as originally thought.  Indeed, the results produced vastly varying results from the different samples, of between 0.0001 m3/m2/hr up to 0.1 m3/m2/hr.  This motivated SmartPly’s Innovation Manager, David Murray and his team to reconsider the formulation for the surface treatment of its boards.

Now, with a structure which is extremely airtight without the addition of a separate membrane, SmartPly VapAirTight has been shown to be six times better than the PassivHaus Institute’s recommendation, with 0.09 air changes per hour.

Manufactured in a tightly controlled factory environment by Coillte in Ireland, the new panel solution comprises a formaldehyde-free thermo-setting resin, which is bonded to the sustainably sourced wood strands. This is then finished with the company’s newly developed flexible coating to provide the moisture vapour transmission resistance.  It also provides a very durable and smooth surface that is ideal for the bonding of airtight tapes across joints under site conditions. 

Meanwhile, for a range with so much science behind it, it is appropriate that SmartPly OSB3 – with its FSC chain of custody and zero added formaldehyde credentials - has played such an important role in the construction of the University of East Anglia’s new Enterprise Building: a project designed to not only meet BREEAM Outstanding requirements, but also full PassivHaus certification.

In addition to main contractor Morgan Sindall, the project team included architects, Architype, UEA’s Adapt Group and BDP Engineers: setting their sights on adopting the most sustainable approach possible to low carbon construction, and an annual primary energy demand of less than 120 kWh/m2.a. 

In total over 11,000m2 of SmartPly OSB3 were consumed in the construction of the Enterprise Building, with 9,400m2 featuring in the floor construction and roof sheeting.  Then to achieve a U-value of 0.11W/m2 k, the outer elevations use a twin wall construction from specialist manufacturer, Cygnum, again using SmartPly OSB3.

The build-up of the wall panels features 18mm taped SmartPly OSB3 on the inside for racking and airtightness, followed by a 140mm cellulose insulated structural stud, a thermal break cavity filled with cellulose insulation and a second 63mm insulated stud. Prior to installation, an external breathable wood fibre board was then added to allow moisture to leave the panel, whilst protecting against condensation and ensuring the thermal insulation of the timber.

“SmartPly OSB3 provided the ideal solution in the creation of our ultra-low carbon timber frame,” said John Desmond, Managing Director at Cygnum Timber Frame. “Utilised in the floors, roofs and internal face of the external walls, it helped us to achieve a very consistent and excellent result for thermal performance with all detailing, jointing and edging completed to the highest standard on site.”

“SmartPly is a material that we are very happy to use for sustainable sites such as this one,” added John Desmond. “The SmartPly factory is also based in Waterford, less than 100 miles from our own manufacturing plant in Macroom, so this helped us to achieve further savings on our carbon footprint.”

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