Over-rafter insulation is the most space-saving form of roof insulation possible and offers the best possibility for later using the roof space. However, it’s also the most complex method as the roof tiles have to be replaced. Avoiding thermal bridges ensures a high degree of energy efficiency. SPAX's product range offers a wide selection of products for over-rafter insulation: countersunk and washer head screws from 8 to 12 mm, with WIROX coating or zinc yellow passivated. SPAX A2 stainless steel, washer head screws with a full or partial thread are available with a diameter of 6 or 8 mm. The washer head allows for high tightening torques and greater spacing between the screws.