With the need for more sustainable building materials currently critical, Rebecca Goldsmith of MEDITE SMARTPLY explains why OSB structural panels can
streamline the fabric-first approach for high performance building envelopes
The updated Part F and Part L requirements of the Building Regulations are considered a crucial stepping-stone to the Future Homes Standard in 2025, which will see a new build house have 75% lower CO2 emissions than one built to today’s standards. To meet these requirements, timber frame construction provides distinct sustainability benefits. Timber is a natural, renewable and low carbon material which along with its versatility, flexibility, and rapid build times make it a highly attractive option for new residential projects.
A key area will be addressing the thermal performance and the design of a building’s envelope. This heightened focus on the building fabric presents both challenges and opportunities. As a route to more thermally-efficient building envelopes, it will become critical to ensure buildings are airtight. Timber frame manufacturers that can provide high-performance, airtight envelope solutions will be well-positioned to meet these changing regulations and capitalise on the move towards low-energy construction.
A Thermal envelope solution
To meet the evolving energy efficiency standards, there is an innovative solution to simplify the path to airtight building envelopes. The increasing demand for double sheathed timber frames in both structural applications and the development of offsite closed panels, led to innovation for producing two certified airtight OSB/3 panels
with airtightness engineered into the panel substrate.
As a solution for walls and ceilings, an airtight panel with integrated vapour control and air barrier can be used as the airtight layer on the warm side of the insulation in timber frame construction systems, helping to create an airtight building envelope. Each panel features alternating layers of wood strands coated with a formaldehyde-free resin and wax binder system to deliver outstanding levels of airtightness. A specialist coating is then applied to ensure vapour resistance and provide a high performance OSB solution for super-insulated and passive buildings, and thereby enabling the elimination of a traditional additional vapour control membrane from the construction.
By seamlessly integrating air and vapour barriers into high-performance OSB panels, this streamlines the installation process, minimising the risk of air leakage that often plagues traditional timber frame structures.
For flooring and roofing, a tongue and groove, load bearing OSB/3 panel can provide improved durability and slip resistance in all site conditions. Similar to airtight panels, it can be used as an airtight layer, contributing to sustainable building practices as well as reducing the energy consumption for heating.
These cutting-edge solutions not only simplify construction but also ensure a certified, proven approach to creating airtight building envelopes that will pave the way for low-carbon, energy-efficient homes of the future.
A home for the future
Testament to the benefits of OSB with built-in vapour and air barrier properties is an exciting regeneration project in Cardiff. Lowfield Timber Frames specified SMARTPLY AIRTIGHT panels alongside a their timber kits for a development of 12, two-bedroom houses in the Heath district of Cardiff.
Built to demanding Passivhaus standards, the homes offer improved health and wellbeing conditions for occupants whilst requiring very low levels of energy for space heating or cooling. Additionally, using timber frame for the construction lowers the carbon footprint of the development.
One of the principal benefits of a Passivhaus build is the significant reduction in energy consumption during the operating life of the structure. This will ultimately lead to reduced energy costs, heating bills, and even lower carbon emissions for the planet.
Showcasing an impressive level of airtightness, the average air test result for the 12 homes in this development came in at below 0.5 ACH. Furthermore, a Larsen truss panel (a lightweight wall extension which creates extra wall space to house insulation) was also used in the project. It was 330 mm deep with the finished wall make-up being closer to 500 mm, allowing for thicker insulation.
Timber frame construction offers housebuilders a clear advantage in meeting the stringent airtightness levels and energy efficiency requirements of the Future Homes Standard. By utilising OSB that features integrated air barrier properties, timber frame manufacturers can deliver airtight, energy-efficient building envelopes needed to comply with these new regulations and put us on a path to net zero.
Rebecca Goldsmith is product manager at MEDITE SMARTPLY