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Wall u value calc

  • #2
    Registered Users Posts: 308 ✭✭ Moggaman


    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???
    Thanks


Comments

  • #2


    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???
    Thanks

    Cavity wall.pdf


  • #2


    Thanks Biker1.


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