Eexternally insulated barn rennovation roof using SEICOSpecial Dry sarking board, internally insulated between rafters with STEICOFlex. Photo Courtesy Kithurst Builders Ltd
RENOVATING A ROOF WITH NATURAL INSULATION Unlike new build projects, a renovation project offers unique problems. Building orientation or proximity to surrounding buildings or vegetation can influence exposure rates of different elevations. Additionally the impact of the weather changes with site location, and all of this means that simple U-value calculations (which are a static processes) cannot fully assess, and account for, all the variables unless a full hygrothermal analysis is completed using appropriate modelling software such as WUFI or DELPHIN. •14•
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ull hygrothermal analysis, and the associated costs, can be daunting but it is possible to incorporate some basic products and design principles, which will ensure a robust and condensation free construction. Specifying a basic vapour control layer as close as possible to the inside is key as it limits the amount of water vapour that can enter the structure. Using a moisture vapour variable membrane such as Steico Multi Renova or Pro Clima Intello Plus ensures that any potential moisture trapped within the fabric can migrate back to the inside during warmer periods. This is particularly relevant for renovation projects as it significantly limits the possibility of moisture forming close to the structural timber elements.
