How much of a fall should a flat roof have?
Traditionally, flat roof falls were created in a couple of ways. The first is to lay screed to a fall. Whilst this creates a robust roof surface, it adds considerable weight to the construction and can require weeks to properly dry.
Alternatively, contractors could lay firrings below OSB or plywood sheets. These are wooden battens which have been cut to a 1:40 angle length ways. . Whilst this construction is lighter than the screed option, it will still require a separate thickness of insulation to be fitted in order to achieve a compliant U-value. This can significantly increase the thickness of the overall construction.
Our tapered roof insulation solutions address these issues. By combining a fall and insulation in a single solution, they can allow both drainage and thermal performance requirements to be met with a slim construction. As we discussed in our ‘Why Choose PIR Insulation’ blog
, in most cases Building Innovation recommend polyisocyanurate (PIR) insulation for tapered applications as the thermal conductivity (λ-value) these boards achieve help to limit the required thickness of the insulation layer.
The light weight of our tapered roof insulation solutions makes them suitable not only for new-build applications, but also for flat roof refurbishments and, in many cases, they can be installed directly above the existing waterproofing layer. The installation is also faster as the tapered insulation solutions perform twin roles and no time is lost waiting for solutions to dry. Building Innovation can help to further reduce project timescales, carrying out surveys and detailed modelling and calculations to ensure the solution performs as expected. We supply clear plans with the materials, allowing site teams to easily understand how the solution should be laid out and can also offer factory cut pre-mitred hips and valley boards reducing onsite labour and waste.