SikaBit,
the Safe2Torch reinforced bitumen roofing system from Sika, has been used to
upgrade the roof of a social housing block in the London Borough of Southwark
as part of a full refurbishment project delivered by Paragon Interserve
(Interserve Construction Ltd).
Located in
the busy Camberwell Road area, Castlemead House was undergoing an internal
refurbishment when Paragon Interserve called in roofing contractor, Hambro
Roofing to carry out repairs to the roof.
It soon
became clear that the condition of the existing felt roof was too poor for
remediation with patch repairs, leading to the installation of a new SikaBit
roofing system as an overlay, providing a like-for-like appearance while
upgrading the performance and service life of the existing roof covering.
Craig
Smith from Sika explains: “The client was keen that any roof refurbishment
should be carried out using a Safe2Torch reinforced bitumen membrane but it was
clear that there was an opportunity to upgrade the existing system with more
advanced bitumen technology. SikaBit’s best-of-both-worlds SBS and APAO hybrid
bitumen technology provided the ideal solution to achieve consistency of
specification while enhancing the roof build-up.
“The
system was specified as part of a warm roof build-up, which also included
SikaTherm tapered insulation, to both enhance thermal performance and improve
drainage by introducing falls and directing direct run-off water to existing
drainage outlets.”
Hambro
Roofing proposed using the SikaBit system for the project after seeing the
advantages of the SBS/APAO hybrid technology, which has been
specially-formulated by Sika for the UK market and Safe2Torch compliance. The
system combines the flexibility and tensile strength benefits of SBS bitumen
with the hardwearing properties and U/V stability of APAO.
After
cleaning and preparing the existing roof surface, the Hambro Roofing team
installed an S.VAP HD SA self-adhesive air & vapour control layer (AVCL).
The roof was then coated with Sika Primer 600, followed by the installation of
the tapered insulation scheme.
SikaBit
SA730 fully self-adhered underlay was then installed onto the insulation layer
and the Hambro Roofing team installed the torch-on SikaBit T940 G cap sheet in
the Safe2Torch zones, before completing the project by installing SikaBit SA940
G self-adhesive cap sheet in all the torch exclusion zones.
Mark
Robinson, contracts manager at Hambro Roofing comments: “The SikaBit system
offered us the flexibility to address unforeseen challenges with the roof. For
example, we discovered during the project that operational hot water pipes were
running through a central wall at roof level. We were able to box in the pipes
and dress the SikaBit system to the boxed area, ensuring it was completely
watertight.
“We were
extremely impressed with the SikaBit Safe2Torch system and how it performed on
this project in delivering a great finish across the whole roof area.”
