Currie & Brown have carried out research looking at how the use of these two approaches might affect the above deck weight of a warm deck flat roof construction. To do this, they selected four new build case study buildings with concrete roof decks. The buildings include 3 offices and a healthcare facility and feature roofs in a range of sizes and complexities.
To ensure a fair comparison, the two build-ups are designed to achieve the same U-value of 0.16 W/m2K. The screed laid to falls option is insulated with Kingspan Thermaroof TR27
, whilst the tapered insulation solution is Kingspan Thermataper TT47
The approximate above deck weight for the two options across the different case studies is shown below.
||Roof Area (m2)
||Screed laid to falls build-up approx. weight (kg)
||Tapered insulation build-up approx. weight (kg)
The results show that by fitting a tapered roof insulation system, it is possible to make significant reductions in the overall weight of the above deck construction. This could help to avoid the need for additional structural or foundation work, saving costs. Further research has also shown that, in addition to these savings, the expected material and installation costs for tapered roof insulation is also as much as 30% lower than screed to fall approaches
Learn more about how tapered insulation systems can help to reduce costs.
From a practical perspective, the lightweight solution also makes it possible for the insulation layer to be fitted directly above the existing roof surface on certain refurbishment projects (where the existing waterproofing is in good condition). This helps to cut down on installation time and, as it is fitted with a dry installation, no time is wasted waiting for the surface to dry. By comparison, screed to fall systems can take 200 days or more to dry in some cases.
Learn more about how tapered insulation systems can speed up installations.