Roofing contractors should no longer be asked to price a project on the basis of ‘roofs to comply with Part L’ either on specifiers drawings or bills of quantity. As the thermal performance of the building design has to be considered as a whole the actual ‘U’ value the roof is required to achieve, or the insulation thickness should be clearly defined.


Thermally broken tube based fastening systems should always be used with the Sika-Trocal Disc System as this will reduce insulation thickness to achieve the required ‘U’ value. Rigid carbon steel fasteners will require a greater thickness of insulation to achieve the required thermal performance.


Always check if the thermal design and specification have been done on the basis of tube based fasteners, which generally they will have been, as the use of rigid one piece carbon steel fasteners will mean the required performance is not being achieved; potentially leaving liability for non compliance with the roofing contractor.


Products should not be marketing to you as being ‘Part L compliant’, as not one element or product can meet Part L without consideration of all the other elements that are likely to effect the energy performance of the building. There are many combinations of design that will affect the Building Emission rate.