HomeMy WebLinkAboutFile Documents.805 Roaring Fork Rd.0019.2018 (59).ARBKDEW POINT CALCULATION
JOB NAME: 805 Roaring Fork Road
JOB NUMBER: 17089.00
DATE: 1/18/18
CALCS BY: JSW
DP @ DP @ DP @ DP @ DP @
20% RH 25% RH 30% RH 35% RH 45% RH
30 33 37 41 48
0
Indoor design temperature (IDT)70
70
R-value
0.17
0.00
0.00
0.94
30.15
0.00
19.00
0.56
0.61
51.43
20.17
43
41
YES
Note: To minimize the potential for condensation problems,
humidity levels within the home must be properly controlled
and adjusted based on outdoor temperatures.
DPA = Dew point at point A (35% RH)
Roof Underlayment
3/4" plywood
4.5" spray foam insulation (R-6.7/in)
Outdoor design temperature (ODT)
Delta T = IDT - ODT
Layer
Thermal Resistance of Proposed Roof Assembly
Outside air layer
Roofing
Batt Insulation (5.5")
Is TA warmer than the DPA?
Inside air layer
R-Total
R-value at A
A: point of condensation analysis
Vapor barrier
5/8" gypboard
TA = IDT - (R-value at A)/(R-Total) * (Delta T)
TA = Temperature at point A
NOMINAL R-49 ROOF
INSULATION
1/18/2018
01/22/2018