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SMARTPLY ULTIMA is an extremely high-performance engineered wood panel (OSB4) suitable for the most demanding structural applications in offsite manufacturing and construction.

Moisture resistant OSB4
OSB4 used for roofing
SMARTPLY ULTIMA used for barn construction
OSB4 construction
ULTIMA used for wall structure

At a glance

  • High strength OSB/4 panel
  • Stronger and more moisture resistant than OSB/3
  • High load bearing capacity
  • Consistent surface
  • No added formaldehyde
  • FSC® certified

Our technical sales team can help you find the right product

Contact us +44 (0) 1322 424900

Specification and sizes

SMARTPLY ULTIMA is manufactured using state of the art ContiRoll® technology consisting of moisture resistant and formaldehyde-free bonding of wood strands, precision strand orientation and continuous pressing. SMARTPLY ULTIMA is available in standard sizes, with the ability to produce large panels up to 2.8m wide by 7.5m long and to a maximum thickness of 40mm (subject to minimum order quantity).

Panel Size
2500 x 1250mm
Panel Size
2440 x 1220mm
Panel Size
1197 x 2397mm


It is a cost-effective alternative in humid and high-load structural applications when compared to a similar performing exterior structural plywood.

Example applications include timber frame, offsite, flooring and walls.

RIBA Approved CPD

If you are a RIBA Architect and would like to learn more about specifying OSB, we have experienced technical sales managers that are able to present a CPD at your practice to you and your team.

This CPD will focus on how OSB is made, its uses and its certifications, as well as covering examples of how it has been used in these applications. It will also cover the uses and benefits of specialist OSB boards for applications such as drylining and flame retardant panels. By the end of the seminar you should have a greater understanding of:

  • What OSB is and how it is made
  • The properties of OSB
  • The advantages of OSB over alternatives
  • The various uses of OSB and how it has been modified for specialist applications

Case Studies


SMARTPLY ULTIMA OSB4 panels help transform barns into state-of-the-art homes

In a £3.6 million regeneration project, 4000 m2 of SMARTPLY ULTIMA OSB4 panels


SMARTPLY ULTIMA can be used in all heavy-duty load bearing applications in service class 2 conditions. Due to the increased strength and rigidity it is an ideal panel for use when higher than standard loads are expected such as flooring or roofing. It is also a panel of choice where increased moisture resistance and reduced panel swelling is required.

SMARTPLY ULTIMA is an OSB/4 grade panel where SMARTPLY MAX is an OSB/3. Panels meeting OSB/4 requirements of EN 300 achieve higher strength and rigidity, but also higher durability and reduced thickness swell due to moisture or water.

To achieve higher strength, rigidity and reduced thickness swell an increased dosage of formaldehyde-free resin and wax is used to make OSB/4 compared to OSB/3.

SMARTPLY ULTIMA can be used in similar applications to plywood but is more uniform and consistent. It is a truly engineered wood-based panel that consists of many strands throughout the thickness of the panel, so its characteristics are averaged out over many more “layers” than plywood giving it more consistency.

SMARTPLY ULTIMA panels can withstand short periods of temporary wetting during construction, although such exposure must be minimised as much as possible, temporary protection is recommended. Water must never be allowed to pool on the surface of panels, particularly at panel edges and T&G joints. If SMARTPLY ULTIMA panels have been exposed to water, it is recommended to allow the panel to dry to the final expected moisture content before installing any permanent floor permanent covering to avoid any moisture degradation of the panels.


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