The Victoria
and Albert Museum, London, is the world’s largest museum of decorative
arts and design, housing a permanent collection of over 4.5 million
objects.A
brand-new entrance, ceramic tiled courtyard and purpose-built
subterranean 1,100sqm gallery for temporary exhibitions was to be built.
The new courtyard will provide an open-aired space right in the centre
of South Kensington.
This area needed a durable, reliable waterproofing solution that
would provide a solution to the various threshold heights throughout the
project.
A Hydrotech system was used throughout which incorporated a typical
inverted roof build up and hybrid construction incorporating Foamglas
insulation. The 1200m2 installation was carried out by Alumasc
Registered Contractor, Knight Asphalt.
What is a Hybrid build up?
The hybrid specification offers the combined benefits of
incorporating a superior thermal performance insulant i.e. PIR or
Foamglas with a hot-melt waterproofing, assuring that the specification
is compliant will all current relevant standards, codes of practice, and
the Building Regulations to provide a secure, free draining and
completely weathertight roof.
Hybrid Insulation SystemAs
you will see from the above graphic the thickness of PIR
(Polyisocyanurate) required when compared to the adjacent XPS (Extruded
Polystyrene) to achieve a given u-value target is substantially less. An
example of where this detail may be used is on a balcony where upstand
heights are to be kept to a minimum with a flush threshold.
For stepped construction(s) provision for drainage would ideally need
to be allocated to both zones. The step transition can occur in various
ways e.g. a two-tier step in the paving utilising adjustable supports, a
timber batten upstand to which the membrane will encapsulate finished
level with the XPS, or alternatively incorporation of a kerb stone as
illustrated in our sketch which may be more aesthetically pleasing.
V&A
utilised Foamglas in favour of PIR in this instance because of its
exceptional fire performance and dimensional stability.
For further product information about Alumasc’s various Waterproofing Systems click here or call our technical team on 03335 771 500.
