Project Overview:
Background:
Drapery Place is a popular student accommodation development in London. Set close to Spitalfields market and key transport hubs, it affords excellent links to the city’s universities. It is home to over 600 students and offers a mix of single and twin studio apartments.
The property owner sought to upgrade the insulated render on the walls that form the development’s internal courtyard. The intention was to provide a high degree of thermal insulation, to preserve the building’s bright, attractive finish, and to maintain the highest standards of safety.
The Brief:
In many places, the buildings of Drapery Place are eight storeys high, so a vital requirement was that the chosen system should meet the most up-to-date requirements for non-combustibility. Specifically, it should exhibit an A2-s1,d0 Reaction to Fire classification (EN 13501-1), using a non-combustible A1 insulation, and it should be suitable for use on buildings of any building height, including those exceeding 11 metres. For added safety, the design called for a system that would be both mechanically and adhesively affixed, ensuring excellent resistance to wind loading and to provide additional structural stability in the event of fire.
The other important criterion was colour: it was determined that the scheme should not change the overall appearance of the building, so the render system would need to be supplied in white to match the original finish.
Design and Specification:
For this scheme, the specified EWI system comprised:
PermaRock Mineral Fibre Dual Density Insulation is hydrophobic and has high laminar and compressive strength. It is made into rigid boards, typically measuring 1200 x 600 mm, and is non-combustible. When used as part of a PermaRock external wall insulation system, fire barriers are not required within the system zone. It achieves Class A1 (EN 13501-1: 2002) and in SBI tests, it produces no smoke or flash-over risk.
PermaRock SiliconeUltra K-Finish is a nano-quartz based render that is water-repellent and demonstrates excellent water vapour permeability. It is through-coloured and highly resistant to the accumulation of dirt, making it especially suited for use in urban environments. It also contains biocidal preservatives help to resist the growth of moss and algae.
The system is suitable for use in all exposure locations in the UK, including those classed as having ‘very severe exposure’ (Level 4) for wind-driven rain.
Performance: U-Values
The insulation has a declared thermal conductivity (λ90/90) of 0.036 W/mK and, on this scheme, the EWI achieved a calculated U-value of 0.20 W/m²K. This made an important contribution to the thermal efficiency of the completed properties.
Result:
The installation of the external wall insulation system was managed by the main contractor and specialist facades contractor, Clarke Facades, who were also responsible for the installation of the other elements of the scheme, following the architect’s specification and PermaRock requirements for the EWI.
The scheme was completed in 2023, producing a system that is bright and weatherproof, and which boasts exceptional performance in the event of fire.