Question I had a flat roof designed wrong/build and trying to find the "correct" answer to fix it.
Currently have the roof build as follows
Joist 200mm @400 Centers
75x50 firings
18 mm OSB
Membrane
50mm PIR insulations
18mm OSB
oprema 3kg per
5Kg per cap sheet
No this doesnt meet the Uvalues
can i just do the following:
3mm skin
12.5 plasterboard
20mm PIR under joist for no bridging
100mm PIR between Joist
Joist 200mm @400 Centers
75x50 firings
18 mm OSB
Membrane
50mm PIR insulations
18mm OSB
Soprema 3kg per M
5Kg per cap sheet
50MM ventilation gap between first 18mm OSB and 100 PIR insulations between the joist
or do we just put 100mm PIR ontop and refelt ect
Currently have the roof build as follows
Joist 200mm @400 Centers
75x50 firings
18 mm OSB
Membrane
50mm PIR insulations
18mm OSB
oprema 3kg per
5Kg per cap sheet
No this doesnt meet the Uvalues
can i just do the following:
3mm skin
12.5 plasterboard
20mm PIR under joist for no bridging
100mm PIR between Joist
Joist 200mm @400 Centers
75x50 firings
18 mm OSB
Membrane
50mm PIR insulations
18mm OSB
Soprema 3kg per M
5Kg per cap sheet
50MM ventilation gap between first 18mm OSB and 100 PIR insulations between the joist
or do we just put 100mm PIR ontop and refelt ect