Wind Load (Roof Components & Cladding)

This sub-page determines wind load of the roof for buildings of any height as per ASCE 7-10 Chapter 30 Part 2. Wind loads are determined for the roof from wind in any direction.
AssumptionsMean roof heights, h ≤ 500 ft (= 150 meters)
Major structural components supporting tributary areas > 700 ft^2 shall be permitted to be designed using the provisions for main wind force resisting systems (MWFRS)
Effective area, Ae for a component or cladding panel is: 
         a.   Ae = span length x effective width > 1/3 span length
         b.   Ae = h^2 / 3 for a vertically spanning concrete masonry unit (CMU) or concrete wall
Enclosed, partially enclosed and partially open buildings. Calculator is not applicable for open buildings.
Applicable for Gable roof with roof angle, θ ≤ 45 degrees, or Monoslope roof with roof angle, θ ≤ 3 degrees. For flat roofs (θ = 0 degrees) use either Gable (G) or Monoslope (M) for "Roof Type". Gable roof is symmetrical.
Sign convention of wind pressures: + is acting toward the surface, - is acting away from the surface
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Roof Components and Cladding (C&C) for buildings of any height
CalculationInputsBuilding properties
﻿﻿Building Classification
:III​
﻿
﻿﻿Enclosed? (Y/N)
:Y​
﻿
﻿﻿Roof Type
:Gable​
﻿
﻿﻿hr
:42ft​
﻿
﻿﻿he
:42ft​
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﻿﻿B
:222ft​
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﻿﻿ L
:204ft​
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﻿﻿Component Name
:Joist​
﻿
﻿﻿Ae =
:208sqft​
﻿
﻿﻿Overhangs? (Y/N)
:N​
﻿
Wind and site properties
﻿﻿Exposure Category
:C​
﻿
﻿﻿V
:170mph​
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﻿﻿ Kzt
:1​
﻿
﻿﻿ Kd 
:0.85​
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﻿﻿Hurricane Region?
:N​
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OutputBuilding properties
﻿﻿ θ
:0.0deg​
﻿
﻿﻿h
:42.0ft​
﻿
﻿﻿ a
:16.8ft​
﻿
﻿﻿Width of Zone 3 (corner)
:16.8ft​
﻿
﻿
Velocity pressure, qh
﻿﻿Kh
:1.05435523493483​
﻿
﻿﻿qh, lb/ft^2
:66.3046050462057​
﻿
Wind pressure coefficients
Roof external pressure coefficient, GCp
﻿
0.2​
-0.9​
-1.1​
-1.1​
Internal pressure coefficient, GCpi
﻿
0.18​
-0.18​
﻿
ExplanationDesign wind load pressures, pWind load tabulation for Roof Components and Cladding. For zone definitions of gable and monoslope roofs, refer to diagrams below.
﻿
Kh​
qh​
Joist​
0​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
​
15​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
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20​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
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25​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
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30​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
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35​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
​
40​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
For z = hr:​
42​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
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42​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
42​
1.05​
66.3​
25.2​
-71.61​
-84.87​
-84.87​
The diagrams are from Figure 30.3-2A to 2D and Figure 30.3-5A to 5B of ASCE 7-22.
❗The roof zone diagrams between ASCE 7-10 and ASCE 7-22 differ. Use the ASCE 7-22 diagrams as provided below.
Gable Roof Zones for GCp
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h ≤ 60 ft and θ ≤ 7°
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Snippet from ASCE 7-22 page 319
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h ≤ 60 ft and 20° ≤ θ ≤ 27°
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Snippet from ASCE 7-22 page 321
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h ≤ 60 ft and 7° ≤ θ ≤ 20°
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Snippet from ASCE 7-22 page 320
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h ≤ 60 ft and 27° ≤ θ ≤ 45°
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Snippet from ASCE 7-22 page 322
Monoslope Roof Zones for GCp
﻿
﻿
h ≤ 60 ft and 3° ≤ θ ≤ 10°
﻿
Snippet from ASCE 7-22 page 328
h ≤ 60 ft and 10° < θ ≤ 30°
﻿
Snippet from ASCE 7-22 page 329
		Kh	qh

Joist	0	1.05	66.3	25.2	-71.61	-84.87	-84.87
	15	1.05	66.3	25.2	-71.61	-84.87	-84.87
	20	1.05	66.3	25.2	-71.61	-84.87	-84.87
	25	1.05	66.3	25.2	-71.61	-84.87	-84.87
	30	1.05	66.3	25.2	-71.61	-84.87	-84.87
	35	1.05	66.3	25.2	-71.61	-84.87	-84.87
	40	1.05	66.3	25.2	-71.61	-84.87	-84.87
For z = hr:	42	1.05	66.3	25.2	-71.61	-84.87	-84.87


















	42	1.05	66.3	25.2	-71.61	-84.87	-84.87
	42	1.05	66.3	25.2	-71.61	-84.87	-84.87
	0.2
	-0.9
	-1.1
	-1.1
	0.18
	-0.18