Snow load thermal factor Ct
Snow load thermal factor Ct
(OP)
I have always thought that the thermal factor Ct for determining roof snow loads should be taken as 1.1 for most homes. From what I understand Ct=1.1 when the roof is ventilated and the insulation between the roof surface and the heated area is greater than R=25. I live in Utah and the roofs typically have an insulation value of R=38 and have standard roof vents. But I review plans and nearly all the engineers in the area use Ct=1.0 when determining snow loads on these roofs. Am I wrong in assuming Ct should be 1.1? What am I missing?






RE: Snow load thermal factor Ct
RE: Snow load thermal factor Ct
RE: Snow load thermal factor Ct
By the way, which is the governing code? IBC or IRC? I have not used IRC. But many times the load requirements are quite different in the two codes.
Given your location of Utah and assuming IBC is the governing code, R > 25, I would use Ct = 1.1.
RE: Snow load thermal factor Ct
Does anyone see any reason why so many engineers in the area would use Ct=1.0 for the conditions described above?
I had finally decided that those who use 1.0 are wrong and I was going to start being nit-picky about it but then thought maybe I should find out what others thought about it. In my county we have snow loads that exceed 200 psf in some places. So thanks for any comments.
RE: Snow load thermal factor Ct
RE: Snow load thermal factor Ct
RE: Snow load thermal factor Ct
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