Knauf Insulation provides the perfect solution for Passivhaus

Sustainability Tue, Aug 13, 2019 9:55 AM

Built from traditional stone and slate, Preston Springs, a four bed home in Leyburn, North Yorkshire, may look like a typical new-build property, but it is far from it.

Designed by architects LEAP, Preston Springs is a Passivhaus, meaning it is ahead of its time in terms of air quality, comfort and reduced energy use. It is one of the only properties of its type in the local area, with just over 1,000 Passivhaus properties in the whole of the UK.

Passivhaus is a voluntary standard for designing and building very low energy properties that offer high levels of comfort for their occupants. To achieve this, the levels of air tightness and thermal performance far exceed those mandated by building regulations.

To meet planning constraints, Preston Springs has been built using a conventional cavity wall construction. The 300mm cavity was fully-filled using two layers of Knauf Insulation Earthwool® 150mm DriTherm 34 Cavity Slabs. Manufactured from Glass Mineral Wool, DriTherm is specifically designed for cavities and uses a water repellent additive to prevent water ingress, making it ideal for its exposed location close to the Yorkshire Dales.

DriTherm 34 was chosen over rigid board insulation. Its structure meant the stone masons could cut and fit the insulation easily on site to ensure it fully-fills the cavity, touching both leaves continuously. This prevents undesirable air gaps that reduce thermal performance. It is worth noting that masonry construction with partially-filled cavities are particularly prone to air gaps between insulation boards or breaks in contact between the insulation and the wall surface.

Secondly, because detailing at junctions between the building elements and the openings meant thermal bridging was virtually eliminated, a more cost effective insulation specification could be chosen.

Principal architect Mark Siddall was confident that DriTherm 34 would deliver the 0.1 W/m2K U-Value required to help the project achieve Passivhaus certification.

For the loft, Supafil Loft Blowing Wool was specified after extensive consultation with Knauf Insulation’s Technical Support Team. While Supafil Loft is very popular in Scandinavian countries, it is not widely used in the UK. However, Siddall believes that blown insulation has a distinct advantage over other insulation types when working towards very high levels of thermal performance.

He said: “The advantage of Supafil Loft insulation is that it can get it into all the nooks and crannies very quickly and easily. This makes it a low-cost solution as far as labour is concerned because installers don’t have to cut and scribe around individual trusses at 400 and 600mm centres – something that would take a huge amount of time. By avoiding these air gaps the roof can be expected to deliver the thermal performance that was specified.”

It was not just the use of Supafil Loft that was unusual on the Preston Springs project, but its depth; 700mm of Supafil Loft was installed, delivering a U-Value of 0.06, which Siddall believes makes it one of the most highly-insulated lofts in the UK.

Siddall explains that to achieve Passivhaus standard, installation is hugely important. He said: “The only way to close performance gaps is through high quality workmanship. I have used the same construction team on several projects. I ensured that the installer had received the necessary training on how to install the Supafil Loft insulation correctly, so I had the quality assurance that it would perform as specified in practice.”

Steve Wise, Programme and Product Development Manager at Knauf Insulation added: “It is always exciting to work on projects that feature products not commonly used in the UK or in applications that differ from the norm, such as the 700mm Supafil Loft at Preston Springs.

“Passivhaus projects allow us as manufacturers to explore what is possible. Preston Springs demonstrates how environmentally-focused design, high performance products and high quality installation can deliver and meet even the strictest thermal standards in a real-world environment.”

Typically, Passivhaus properties achieve a 75% reduction in space heating requirements, compared to a standard UK new build. While monitoring is ongoing, anecdotal evidence from the owners show that Preston Springs is performing as designed, maintaining a temperate climate throughout the year. During ‘The Beast from the East’ the internal temperature was a reported 19°C without heating, while the external temperature plummeted to -6°C.

Furthermore, the owners report they are delighted with the low energy bills thanks to the very high thermal performance of the insulation combined with the heat recovery system.

Featured News

Specification news
Beko plc Appliance Partners’ parent company,...

Beko plc Appliance Partners, the specialist appliance solution provider to...

Read More >>

Specification news
Stunning property restored with Schlüter solutions

Tucked away in Sutton Bonington in Nottinghamshire sits a beautiful Grade II-listed...

Read More >>

BUILDING PRODUCT LIBRARY - LATEST BROCHURES

REVO.Prime TSA 325 NT Brochure

REVO.Prime TSA 325 N...
By GEZE UK Ltd

Download Now >>

Natural ventilation strategy for Sunderland SEND school Brochure

Natural ventilation...
By Passivent

Download Now >>

Squash Court Flooring Brochure

Squash Court Floorin...
By Junckers Limited

Download Now >>

Junckers Acoustics Floor System Brochure

Junckers Acoustics F...
By Junckers Limited

Download Now >>

BUILDING PRODUCT DIRECTORY - LATEST PRODUCTS

Ei1025 Environmental Sensor
Ei1025 Environmental Sensor

Discreet and secure, the Ei1025 Environmental Sensor can be placed throughout a property to monitor...

Read More >>

Ei1000G SmartLINK Gateway
Ei1000G SmartLINK Gateway

The Gateway and Cloud portal use Aico’s SmartLINK technology to bring together data from all...

Read More >>

Ei3030 Multi-Sensor Fire and Carbon Monoxide Alarm
Ei3030 Multi-Sensor Fire and Carbon Monoxide Alarm

The Ei3030 is a multi-sensor Fire & Carbon Monoxide (CO) Alarm. Containing our proven and dependable...

Read More >>

CONSTRUCTION VIDEOS - LATEST VIDEOS

Forma aluminium column casings for Winchester College
Forma aluminium column casings for Winchester College

In progressive and dynamic business sectors, such as construction, it’s natural to be forward...

Watch Now >>

Decorative metal bulkheads & column casings for Tesco Extra, Birmingham
Decorative metal bulkheads & column casings for Tesco Extra, Birmingham

Decorative aluminium horizontal bulkheads more than 100 metres long have been supplied and installed...

Watch Now >>

Vecta building linings for the perfect finish
Vecta building linings for the perfect finish

More than 150 sq.m of Vecta aluminium wall lining and a feature bulkhead have been manufactured and...

Watch Now >>