Don’t get lost! These are tech pages only, go to HOME for main page list
E&OE The text and graphics of this website are Copyright © 1996-
If you found this page informative please tell others by clicking the +1
Insulation = 220mm (average)
Eg TR26: K = 0.024, R = 0.22/0.024 = 9.2, U-
Rest of roof standard values: Ext.surface = 0.045, Permadeck = 0.06, upper deck =
0.13, thermal break = 0.13, t&g liner = 0.13, int.surface = 0.105. Giving a total
of 0.6. The whole roof resistance is 9.2+0.6 = 9.8, and the U-
If this is too good, a U-
Example3: Timber deck Eco Roof with Exposed Beams
DryPly™ over parapet
Permadeck trim on o/s
18mm DryPly™ countersunk fastenings to suit
Tapered insn. eg 50 -
Thermal break layer, 18mm sheathing ply
If the laminated beams are sloping, the tapered insulation can be a standard flat board instead, giving greater insulation thickness.
300 x 100 exposed laminated beams at 1200 centres
Permadeck 20, BBA 93/2967
The ‘standard’ highly insulated roof with a single ply membrane poorly attached to insulation has proven to have many drawbacks. These soft roof designs are vulnerable to damage, difficult to trace and repair faults and have very limited design flexibility.
Whereas Permadeck, bonded to its DryPly™ deck, can easily withstand impact & abrasion and have anything designed onto it or into it: gulleys, rooflights, vents, micro generation, flues, air con etc.
Permadeck 20 on 12-
k fastenings on 50mm insulation on vapour barrier on metal deck to falls or tapered insulation.
Example1: Metal deck Eco Roof inc thermal break & Permadeck solid roof
Ideal where a solid roof is required. Can be walked on, can incorporate gulleys within the top insulation, easy fix for rooflights, water housings, parapet details, micro generation mounts, ventilators, aircon, heat pumps etc.
Example2: Timber deck Eco Roof
18mm ply with countersunk fixings into lower deck. 50mm or greater insulation on
vapour barrier on 18mm sheathing ply on firring on joists with ~120mm insul-
Permadeck on DryPly with trim to o/s face.
Roofs over high high humidity areas such as bathrooms, laundry areas, swimming pools should have an additional vapour barrier below the joists. Downlights and wiring should not penetrate this layer.
5 or 7w LED
Permadeck20 BBA 93/2967