Is there one r value I must go by, or can I choose the one I want? I'm looking at three different spec sheets and get three different r values, from 1.03 and 1.10 per half inch, to 2.33 per inch(1.16 per half inch). I'm trying to keep the hearth flush with the floor and only have about 1 1/2 inches to work with. I need a minimum r value of 2.5 If I use the highest of the three specs I can do:
1" of Micore = r 2.33
1/2" Durock = r .26
1/4 tile = r .08
Total R Value = 2.67
If I use the lesser values of Micore 300 and cement board and tile I come up short of r2.5 - more like r 2.37
Will an inspector ask? Maybe more important is the safery factor. Will the hearth provide the required heat resistance with the variation between the high and low values? In other words, if I use the r 2.67 value am I really only getting the r 2.37?
Micore 160 would solve the problem but not available anywhere close(not even sure I could order 1 sheet out of state)
1" of Micore = r 2.33
1/2" Durock = r .26
1/4 tile = r .08
Total R Value = 2.67
If I use the lesser values of Micore 300 and cement board and tile I come up short of r2.5 - more like r 2.37
Will an inspector ask? Maybe more important is the safery factor. Will the hearth provide the required heat resistance with the variation between the high and low values? In other words, if I use the r 2.67 value am I really only getting the r 2.37?
Micore 160 would solve the problem but not available anywhere close(not even sure I could order 1 sheet out of state)
