The Landmark Offices, Manchester

The Landmark Offices, Manchester

Landmark is a 180,000 sq ft prime office development located in Manchester’s premier business district. Partially built off-site, it has been designed to achieve the highest sustainability standards – a BREEAM rating of ‘excellent’ and an Energy Performance Certificate rating of A so the thermal performance of its insulation was hugely important.

Building regulations in England and Wales ban the use of combustible materials on all buildings over 18m. With 14 floors and a roof height of 27m, the architect, Squire and Partners, specified non-combustible insulation with Euroclass A1 reaction to fire classification.

With this in mind, external wall sub-contractor FK Group consulted the Knauf Insulation Technical Support Team for advice about which insulation to use. The team conducted 3D U-value calculations and determined that Rocksilk® RainScreen Slab in thicknesses of 50mm, 100mm and 150mm would achieve the desired U-value.

Rocksilk® RainScreen Slab

Rocksilk® RainScreen Slab is manufactured from Rock Mineral Wool and has a thermal conductivity of 0.034W/mK. It is BBA certified for use over 18m and has the best possible Euroclass A1 reaction to fire classification, meaning it met the required specification for fire safety.

FK Group also sought advice about what to do if the Rocksilk® RainScreen Slab was exposed to rainwater during installation. There is a common misconception that the thermal performance of Mineral Wool will be permanently compromised if it gets wet, but this simply isn’t the case. Rocksilk® RainScreen Slab has been developed for external applications – its fibre matrix promotes water run-off, and it contains moisture-repellent additives in the binder. This ensures it can withstand higher levels of exposure to moisture during installation. Knauf Insulation also provided advice on the storage of insulation on site to protect the insulation from prolonged exposure to rainwater prior to use.

Offsite construction

Landmark was built using an offsite construction method. Decorative concrete rainscreen panels were manufactured by Techrete in Hull. Rocksilk® RainScreen Slab was fitted offsite before the entire panel was transported to Manchester and craned into position on the concrete frame.

The Knauf Insulation Specification Team provided further support by carrying out visits to both the Techrete manufacturing facility and the construction site to check the insulation was being installed correctly.


As well as its thermal and fire performance, Rocksilk® RainScreen Slab offers considerable sustainability credentials. It is manufactured with ECOSE® Technology, Knauf Insulation's unique bio-based binder that contains no added formaldehyde or phenol. ECOSE® Technology is made from natural raw materials that are rapidly renewable and is 70% less energy-intensive to manufacture than traditional binder, so it is more environmentally-friendly.

Products made with ECOSE® Technology are soft to touch and easy to handle. They generate low levels of dust and VOCs and have been awarded the Eurofins Gold Certificate for Indoor Air Comfort. This is beneficial when insulation is being installed offsite in an enclosed industrial environment.

Enhancing the St Peter’s Square heritage

Murray Levinson partner at Squire and Partners said “Landmark is an important project for Squire & Partners, representing our first completed new build project in Manchester. When we were approached to design Landmark, we recognised an opportunity to extend the cluster of prime office buildings of the adjacent St Peter’s Square southwards. Our design concept aligned itself with the new developments, whilst creating a building which enhanced its specific site heritage and context.

“A priority for both ourselves and the client was to create a building with exceptional sustainability and wellbeing credentials, and we are proud to have achieved BREEAM Excellent and EPC A ratings,” added Levinson.

Thanks to its thermal performance, fire safety and environmental credentials, Rocksilk® RainScreen Slab will contribute to Landmark achieving the world's foremost environmental assessment method and rating system for buildings. All of which means this will truly be a landmark building both visually and in terms of sustainability.

For further information about how our insulation can contribute to BREEAM, click here.

Client FK Group