Moggaman wrote: »
Hi . My design involves a sand cement render externally on a 100mm outer leaf, 200mm blown bead cavity , 100mm inner leaf with sand cement and skim finish. I attempted a u value calc .. see below.Can you tell me if I am thereabouts or am I missing something...
seems to me if you could guarantee effectiveness of PIR ie non thermal looping it is a no brainer in terms of u values...
Appreciate it . Thanks
Resistance to external surface 0.048 r
External render - 0.347
Concrete block outer leaf standard 0.075
Blown beads 200mm thick at 0.032 conductivity = 6.25 r
Concrete block inner leaf standard -0.075
Internal sand cenent and skim - 0.075
Resistance to internal surface - .122
Total resistance- 6.99
U value 1/r = 0.143???