Going soft on exterior insulation

// the building envelope

Technical Editor Bruce Meechan catches up with Darren Snaith, Director of Refurbishment and Regeneration at ROCKWOOL UK.

ROCKWOOL may be thought of as being at the rigid end of stone wool insulation, but there are two very good reasons for my saying that I think the manufacturer has become more flexible and innovative when it comes to the subject of exterior wall insulation The first is in the form of a dual density board developed for retrofit projects; while the second concerns a brand new software tool package which is ideal for helping social housing landlords predict the benefits they could achieve by cladding their various property types.


Both of these topics and more were included in my conversation with Darren Snaith when we met at the Hammersmith offices of ROCKWOOL.


Referring to some of the governing forces in the marketplace, Darren spoke about the changes to ECO saying: “What the changes have done is challenge people to consider different ways of funding projects; now the housing associations and local authorities are more innovative in their approach, thinking longer term and not relying on schemes that can fluctuate. The need for EWI is very much there in terms of upgrading buildings and lifting residents out of fuel poverty.  And the funding route may very well change again in the near future. As well as thinking about their return on investment, social housing providers are now comparing EWI with other measures such as kitchens and bathrooms on a value for money basis.”


Darren explained the breadth of ROCKWOOL’s offering for its REDArt® Façade System: “We have architectural technicians who produce conceptual design and CGI’s so the client knows what the project will look like, as well as detailing around challenging areas such as, roof lines, service penetrations, plant rooms and even bin stores – they will visit site and decide how exactly the exterior wall insulation should interface with each specific junction. We also have a national team of site support technicians who visit projects to offer advice and support throughout the project and to ensure that the systems are being installed correctly around apertures and interfaces.
“It is their job to perform pull-out tests which determine the strength of the original substrate therefore the type of mechanical fixings required.  This is crucial because the fixings can vary depending on the substrate type or house type.  It’s all about the level of support you offer the client throughout the entire project, not just delivering the physical product.”


That support has recently been ratcheted up through the introduction of the ROCKWOOL SAP Sensitivity Tool that ROCKWOOL has developed in conjunction with Cardiff University, which is equally applicable to new build applications as it is to the millions of existing solid wall structures still waiting to be upgraded.


For anybody like myself who has witnessed an Energy Performance Certificate being carried out on a home – and been dismayed at the risibly approximate estimations of the building elements, especially the walls – then ROCKWOOL’s SAP Sensitivity Tool appears to present a similar step change as the I-phone to a fax machine.  


What is more, Cardiff’s research has included carrying out countless specimen calculations on all the different building types that an RSL is likely to have in its stock: from the Victorian terraces and post-war semis, through to high rise flats.


Amongst the parameters which can be compared are location, orientation, typology, the various glazing options, energy sources including biomass, existing bills and even a valid estimate of the contribution thermal mass will make to a property’s characteristics. Then the simulation is run again adding in different thicknesses of the three insulation types – including the dual density - ROCKWOOL can offer for EWI. The final analysis then offers accurate figures on the fuel savings and carbon reductions which could be achieved.


Darren summed up saying: “If you’re looking at a place which has been constructed to 1980 Building Regulations you can go through and set all the parameters for your base, and then go through the calculations to look at the improvements achievable. It’s a tool that demonstrates the infinite variables and value of our system and also enables our Business Development Managers and partners to examine all aspects of a project with clients."

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