During the conversion of a Grade II Listed Water Tower into a high specification home, Andy Critchlow, Director of AEW Architects was faced with the challenge of how to create a thermally efficient building from a structure that when originally built was never intended to be a home. To achieve excellent thermal efficiency, low environmental impact and help deliver a building fit for its new purpose, AEW specified a range of PIR insulation products from market leader Celotex.
Built in 1881, the water tower had lain dormant for over 50 years until purchased for a private residential conversion in 2010. Due to the nature of the building, and to retain the existing brickwork aesthetic as agreed with the Local Planning Authority, the insulation had to be installed on the inside of the existing structure. Combining the highest thermal performance and the thinnest possible solution, AEW specified four different Celotex products for use in various elements of the build.
To minimise loss of space, the insulation chosen had to be as thin as possible whilst achieving exceptional thermal performance. Celotex supplied its TB4000, GA4000, XR4000 and FF4000, which were installed by specialist contractor Archway Building Solutions throughout the ground floor of the structure as well as three additional floors, along with all external walls and stud walls, the roof and a new extension.
The conversion resulted in considerable remodelling of the brick building, including installing new internal floors and rooftop extension supported off a new steel frame, sealing and waterproofing of the floor slab, masonry walls and roof.
Celotex TB4000 was used in the lining of the tower walls at a thickness of 40mm, fitted between the existing masonry and new stud wall, and GA4000 was used at a thickness of 65mm between the studs of the new wall. With a breadth of range unrivalled by any other PIR manufacturer, TB4000 and GA4000 offer multi-purpose insulation solutions and have achieved an A+ rating when compared to the BRE Green Guide 2008 – outperforming typical PIR by 15% for environmental impact.
In the ground floor, approximately 85m2 of Celotex FF4000 in a thickness of 70mm was supplied. Ideal for installations with underfloor heating, the BBA certified and Ofgem approved FF4000 provides high compressive strength, better dimensional stability and resistance to site traffic during installation whilst the foam structure ensures better pipe clip retention.
For the two additional floors, Celotex supplied 270m2 of its TB4000 in 35mm thickness. Offering low emissivity foil facings, TB4000 is the thinnest PIR available and has been developed to eliminate the common occurrence of localised thermal bridges and greatly reduce heat loss – proving ideal for refurbishment projects.
For the stud walls and roof to the rooftop extension, Celotex developed and supplied a specification to help achieve U-values of 0.21W/m²K and 0.20W/m²K respectively. To achieve this, approximately 16m2 of XR4000 at a thickness of 120mm was installed into the roof top extension walls, with an additional 40m2 of 40mm thick TB4000 provided to insulate the new zinc-clad flat roof.
The innovative refurbishment and remodelling project was filmed for the Channel 4 show The Restoration Man, hosted by presenter and architect George Clarke. Attracting approximately two million viewers per episode, the show proved an excellent way to demonstrate how much can be achieved on challenging construction sites with a carefully considered, high quality design and specification of insulation.