Due to the tragic event at the Grenfell Tower in 2017 and subsequent building fires in the UK, Facades and Fire Safety has, rightly so, elicited increased focus on the fire performance of products used in the constructions of today. It has had a huge impact on the high-rise sector and has resulted in one of the biggest changes in Regulation 7 and Approved Document B (ADB) that has been experienced for a number of years.
Whilst Regulation 7 and Approved Document B (ADB) are the regulatory and advisory documents, it was unfortunately the case that they were considered ambiguous and therefore the reading and interpretation of them could end up with flawed or potentially dangerous outcomes in both design and specification. The update in late 2017 sought to improve and strengthen the message, language, terminology and examples in order to simplify the information and attempt to remove any ambiguity and achieve mutual understanding of the requirements.
One of the most important amendments was the shift in classification of materials within ADB and the removal of references to BS 476-6&7 which previously classified products for Spread of Flame. The issue with the classification was that it only considered the reaction of the surface of the material being tested, and did not consider the combustibility of the whole product.
Due to the performance requirements of certain critical, flexible components within the external façade, such as
breather membranes, the ability to achieve a non-combustible classification is inhibited by the nature of the materials
from which they are made.
This was understood by the regulatory writers and therefore a list of exempt components has been included in Approved
Document B to accommodate such products. Manufacturers are investing time and money into this area in order to
provide an achievable fire classification without impeding the performance of the product.
In the amendment to Document B in November 2018 the required fire classification for breather membranes is stated to
‘Membranes used as part of the external wall construction should achieve a minimum classification of European Class
Traditionally breather membranes are mechanically fixed on low rise and taped on high rise. These membranes tend
to shrink away from fire, however standard tests utilise a single focused burning flame which is widely challenged as the
correct way to test a membrane for this application, and is not reflective of a real time scenario.
There is a clear benefit to using a self-adhesive membrane due to the material being fully adhered to the substrate.
Therefore, there is no air gap behind the membrane and the substrate, meaning no flames can pass up the back of the
membrane, as could happen with a loose mechanically fixed product.
Membranes & Fire Performance
The increasing use of a self-adhered breathable membrane in high-rise development over A1 and A2 sheathing boards,
has resulted in it being carefully considered in terms of performance in a fire context, which is of critical importance.
Wraptite has therefore undergone classification to BS EN 13501-1 over a wide range of appropriate substrates
The results from these tests showed that Wraptite achieved a Class B-s1-d0, the highest classification that can be
achieved from a polypropylene based membrane.
This performance allows designers to utilise the weather protection and air leakage performance benefits of Wraptite
with confidence, even in the most demanding of applications where fire safety is critical.
However, if using a membrane in the cavity, either on lower rise buildings, or in high rise to add further protection to the
system, products which actively resist fire, such as Fireshield are ideal.
Fireshield is a more rigid mechanically fastened product compared to lighter weight polypropylene membranes, in part
due to the nature of its glass fibre backing. The weight and robustness of the product makes it less likely to billow away
from the substructure, forming air gaps behind when installed correctly.
Fireshield’s specialist coating eliminates fire spread across the surface of the membrane and it is fixed using mechanical
fixings. The intumescent facing actively resists the spread of flame by preventing it from taking hold due to the ‘foaming’
effect (expanding when it interacts with fire).
The A. Proctor Group provide a number of Breathable Membranes and Vapour Control Layers which have in depth
testing to ensure confidence in the performance of the products in situ.
Fireshield is a vapour permeable walling membrane with a fire proof surface. Fireshield is suitable for all walling applications
including those in multiple storey buildings. Its unique coating doesn’t just resist fire, but eliminates fire spread. It is installed and
fixed to the substrate in the same manner as standard breather membranes using mechanical fixings.
Fireshield can also be used on the external cavity face to improve the fire robustness of closed panel assemblies when installed to the
external sheathing alongside suitable non-combustible internal linings.
Fireshield is the first fire resistant vapour permeable membrane approved for inclusion in the Structural Timber Association’s tested
product listing for fire robustness during construction. As part of such a construction, Fireshield acts as part of a system to limit the
spread of fire to adjacent properties, allowing for reduced spacing to neighbouring properties and maximising development space.
Fireshield (right) and a competing fire retardant
membrane (left) are fixed to a 10mm OSB panel
with staples. A butane torch is positioned approx.
10cm from the face of the membranes at a 45
degree angle. Two cameras capture the view
from front and back.
After 1 Minute
On the left side, the competing membrane
retreats further from the flame and the OSB
begins to burn. On the right side, the flame
has caused Fireshield’s intumescent surface
to react and ‘puff up’ which protects the
membrane and the OSB.
After 20 Minutes
The competing membrane exposed the
OSB directly to fire from the outset and, as a
result, the OSB burned completely through
before the test was over. The torch over
Fireshield was left on for a full 20 minutes.
Even though the membrane itself did not
catch fire during that time, the front-side of
the OSB panel only received minor scorch
marks and did not ignite.
Part B compliant for buildings over 18m/ 11m in Scotland
Unique composition actively reacts to prevent fire taking hold
Vapour permeable walling membrane for use either directly onto
sheathing or insulation
Class B, s1-d0 but performs differently to other similar class
Complies with BS5250, BS4016 & NHBC requirements for vapour
permeable walling underlays
Robust and durable composition
Airtight for enhanced energy efficiency
Procheck A2, is a fire resistant, vapour and airtight membrane. Procheck A2, with its Class A2-s1,d0 fire classification to BS EN
13501-1, makes no contribution to fire development. Its composition comprises of the glass fibre backing, with a pure aluminium
foil and clear lacquer coating. This composition affords the membrane its Class A2 performance as well as giving it a high degree
of vapour controlling properties. The membrane comes with a high vapour resistance, as well as being airtight, which allows its
use as an AVCL in the construction. Providing high levels of airtightness can enhance the thermal efficiency of the building.
The integral foil layer, with its protective clear lacquer coating, gives this A2 membrane the unique added benefit of having a low
emissivity surface. This means that the membrane, when installed with the foil face next to a service cavity, with a minimum depth of
19mm, will provide additional thermal performance to the overall wall construction.
Procheck A2 air and vapour tight membrane improves energy efficiency and reduces the risk of condensation.
Fire resistant to A2,s1-d0
Water vapour diffusion tight
Reflective material, emissivity <0.05
Clear lacquered aluminium surface allows for low
Easy to install
Robust and able to withstand tough site conditions
BRE approval in buildings over 18m in England and
Wales, and over 11m in Scotland
Procheck FR200 is used as a fire retardant vapour control layer in roof and wall structures in new build and renovation projects.
It has a Reaction to Fire classification of B-s1,d0 which provides assurance of fire performance for the structure. Procheck FR200
air and vapour tight membrane improves energy efficiency and reduces the condensation risk.
Independent assurance of fire performance
Class 0 to BS 476 parts 6 & 7 and EN 13501-1 B-s1,d0
Improved energy efficiency
Reduced condensation risk
Lightweight and easy to install
Water vapour diffusion tight
Withstands tough site conditions
Spacetherm SLENTEX® A2
Spacetherm SLENTEX® A2 is a flexible, high-performance, silica aerogel-based insulation material of limited combustibility used
for exterior and interior applications. Supplied in a variety of finishes**, the substantial layers of Spacetherm SLENTEX® A2 meet
the requirements for A2 classification. The product is used to optimise the thermal performance and fire properties of façade
systems in a number of ways. These include enhancing the thermal performance of the ventilated façade, and addressing thermal
bridging in the façade. Spacetherm SLENTEX® A2 is also useful in minimising thermal bridges around windows in areas such as
window reveals and roller shutter cases.
With a thermal conductivity of 0.019 W/mK, Spacetherm SLENTEX® A2’s performance, coupled with its superior fire performance,
qualify it as one of the best insulation materials available worldwide. Engineered for space-critical applications, the product offers low
thermal conductivity, plus breathability allied to hydrophobic characteristics. Its flexibility and ease of use has proven it as the insulation
material of choice in many applications and for a wide variety of clients.
Class leading fire performance from an Aerogel insulation
Wraptite is a unique patented external airtight and vapour permeable, self-adhered membrane which solves the problem of
reliably achieving airtightness in buildings. Applying Wraptite to the outside of the building will mean there are fewer penetrations
for services therefore the likelihood of expensive remedial work is greatly reduced. Wraptite is lightweight, easy to install
and fully bonds to virtually any substrate, with a key benefit being its speed and ease of installation, negating any requirement
for sealants or tapes. This new approach saves on both the labour and material costs associated with meeting the demands of
modern energy efficiency requirements in both commercial and residential buildings.
Wraptite has received BBA certification for use in roofs, walls and modular floor construction making it an ideal choice for commercial
projects with large uninterrupted façades. Its unique patented technology means it is the only self-adhering vapour permeable air barrier
certified by the BBA. Wraptite is compliant with Part B regulation changes and also has BRE acceptance for use in the external wall
systems of buildings over 18m in height, both as a continuous layer on sheathing board, behind fire classified insulation, and for use to
tape joints in insulation behind rainscreen.
Water resistant yet vapour permeable and airtight membrane
Self adhered to avoid air bypass
Full adhesion avoids damage during transportation of modular timer
frame kits to site
Part B compliant for buildings over 18m / 11m in Scotland under
BRE acceptance for buildings over 18m high
Class B, s1, d0 on A2, s1, d0 or A1substrate with minimum density
of 653kg/m3 and 9mm thickness
Can reduce wall thickness
Leading airtightness performance
Removes requirement for complex internal detailing and may
negate requirement for VCL internally
Reduces thermal by-pass
Allows temporary protection until primary external covering
Provides durability and reduced risk of tears and subsequent
Unique patented technology
Continuous airtight seal
Simple detailing at junctions and corners - less EPDM required
Wraptite Liquid Flashing
Wraptite Liquid Flashing is a high-quality, gunable, elastomeric, polyether, liquid applied flashing and detailing membrane.
It bonds to most construction materials, such as aluminium, brick, concrete, wood, vinyl, and exterior sheathing boards. Wraptite Liquid Flashing is compatible with our entire range of vapour permeable products for joint detailing in exterior sheathing panels.
Wraptite Liquid Flashing is ideal for use in complex details. It can also be used to protect the leading edge of the Wraptite membrane or tape from water penetration if the edge cannot be protected by overlapping in a shingle fashion.
Airtight & vapour permeable
Continuous seal and system approach
Can be applied in damp conditions
Does not peel back when left exposed
Does not create build up in rough openings
100% solvent free
Bonds to most construction materials
Easily applied and spread
Does not harm foam insulation
A useful way of stopping unnecessary air leakage around openings and overlaps is to use Wraptite Tape, an airtight, tear resistant
tape with high vapour permeability for internal and external applications. Wraptite Tape’s flexibility facilitates ease of application and detailing, while its resilient composition resists punctures and tears during construction. It can be left exposed for up to 120 days during construction and has a wide operating temperature range (-40°C to +100°C). Wraptite Tape is also available with a split release liner for ease of installation.
It fully bonds to all standard substrates, with no primer required, suppressing air leakage around joints, openings and penetrations.
It is also suitable for permanent airtight sealing of membrane overlaps and for taping insulation joints. Wraptite Tape’s high vapour
permeability allows damp sheathing to dry quickly and moisture vapour to escape. This ensures good indoor air quality and reduces the likelihood of mould, mildew, condensation, timber distortion and metal corrosion. Wraptite Tape contains no VOC’s.
Vapour permeable tape used to protect exposed joints in insulation
Easy to use when detailing joints
Ultimate airtightness accessory
Can seal joints in mechanically fastened air barrier
Provides a continuous airtight seal
Lightweight and flexible
Wraptite Preformed Airtight Corners have been developed for the difficult areas around doors and windows where maintaining
good air barrier continuity is difficult and time consuming. Wraptite Corners’ simple design and installation process makes sealing
openings against air leakage simple, just peel off the release liner, stick the corners in place, then install the Wraptite membrane
as normal. This helps achieve the best possible results in the shortest possible time.
Once installed, the corner sections provide the same vapour permeable air barrier performance as the Wraptite membrane itself,
ensuring air leakage and water ingress are minimised without trapping construction moisture or causing condensation.
Ensures continuity of airtightness measures
Simplifies complex detailing
Lightweight and flexible
Façadeshield® UV is designed specifically to ensure the building fabric maintains good water resistance and breathability behind open jointed cladding.
Leading research has culminated in a non woven breathable membrane that combines exceptional water resistance and UV resistance with the aesthetically pleasing dark colour to provide a “shadow” appearance within open rainscreen façades.
Façadeshield UV enhances the air tightness of the building whilst reducing the risk of condensation due to its’ high vapour permeability, yet airtight fabric. The product comes with the reassurance of a CE Mark showing the product’s fitness for purpose in the façade application, making it the obvious choice behind open jointed façades.
To protect the membrane from mechanical damage, the joint openings in the façade covering have to be less than 50% of the area, and maximum 50mm wide*.
Provides secondary protection to open jointed & perforated façades
Aesthetically pleasing behind open façades
Provides externally applied airtight layer for continuity of air barrier
Has long term durability
Class B fire performance
Robust and able to withstand tough site conditions
Can be fully exposed for up to 12 months
Fire Solutions In Practice - Goldfinch Court & Balfron Tower
Meeting the challenge of delivering fit for purpose fire
protection depends a variety of solutions tailored to individual
project requirements, Ensuring the specification, installation and
application are well matched is the key to a successful design.
At Goldfinch Court, client Hills Partnership working with PCKO Architects
undertook this project to replace and upgrade an existing residential facade
comprising combustible ACM panels and rigid foam insulation.
In addition to mineral fibre insulation and non-combustible cladding panels, the
architects specified the Fireshield vapour permeable membrane from the A.
Proctor Group Ltd.
Correctly installed in accordance with the A. Proctor Groups guidance by
contractors Facade Cladding Solutions, Fireshield has a unique intumescent
composition that actively reacts to prevent fire taking hold. This unique coating
extinguishes fire rather than just resisting it, and significantly reduces the formation
of droplets and smoke.
Fireshield complies with BS5250, BS4016 and NHBC requirements for vapour
permeable walling underlays, and also carries BBA certification and has LABC and LABSS registered details. It is installed and fixed to the substrate in the same
manner as standard breather membranes using mechanical fixings.
Applications include both commercial and residential buildings including apartments
and student accommodation, as well as rainscreen cladding and applications over
Another project, The Balfron Tower (left image) involved the
upgrading and refurbishment of a Grade II* listed 1960’s building
in the London Borough of Tower Hamlets, originally designed by
the renowned architect Ernö Goldfinger.
The existing wall construction meant that space for traditional
insulation was limited in some instances. Spacetherm SLENTEX®
A2 was capable of achieving the BRE’s surface condensation
analysis target temperatures of 16°C, with minimum loss of space.
The concrete walls around the stairways in each apartment were
particularly space critical and identified as a weak point for cold
The original specification would have required an additional
insulated wall lining of 145mm, whilst using Spacetherm
SLENTEX® A2 the required high-performance insulation was
achieved in less than 60mm.
Total Solution Capabilities - Concept to Completion
Years of investigation, research and development has
resulted in new and innovative ways to protect buildings,
both whilst being constructed and once built.
The A. Proctor Group’s range of construction membranes
combines this expertise to provide comprehensive
protection to building envelopes from both the inside and
the outside of the structure, whatever design criteria may
The A.Proctor Group operates out of The Haugh in Blairgowrie, which has belonged to the family since the early 1900’s and now acts as the Head Office for the Administration departments and Customer Services.
Condensation Risk Analysis
Condensation can significantly reduce the effectiveness of
insulation, and result in damage to the building fabric.
A Condensation Risk Analysis evaluates the likelihood of
interstitial condensation in your roof or wall construction.
These calculations are regularly required by building control to
demonstrate compliance with building regulation requirements.
Calculations are performed free of charge when using our
Dynamic Assessment With WUFI
The industry standard Glaser method considers only the
movement of water vapour in a single direction. Where more
complex analysis is required, hygrothermal simulation using the
WUFI software can provide insight into the effects of capillary
action, stored moisture and precipitation.
The movement of moisture is analysed in much more depth,
using real world climate data to provide an hourly analysis, rather
than the monthly averages that Glaser works with. Materials
which are particularly able to store moisture perform very
differently under the two methods.
Our range of Performance Specifications & BIM content,
covering our Condensation Control Membranes, External
Airtight Barriers, Acoustics Flooring Solutions, Ground Gas
Protection Systems & Thermal Insulation range is now available
in a combination of Revit Project files (.rvt), Revit Detail
Component files (.rfa), Industry Foundation Class files (.ifc)
& PDF format.
Technical & Sales Support
Our technical back-up has always been an integral part of our strategic development, with an
outlook based on advanced technical solutions, rather than commodity driven.
Our dedicated technical team is focused on providing high quality advice and support to our
customers all the way from drawing board to site.
Online Technical Advice
WUFI & U-Value Calculations
Condensation Risk Analysis
8:30am - 5pm, Mon - Fri
01250 872 261
01250 872 727
A. Proctor Group Ltd., The Haugh, Blairgowrie, PH10 7ER