This is an Archive of the ASCE7-05 Windload Program for Wall Components and Cladding

The program displays the Wall Components and Cladding design pressures for the selected conditions. I use these programs to verify the design pressures provided by the architects or to create them for estimating or engineering purposes. It is highly recommended you review the building code to understand where the information comes from. Refer to the links page for various building code web sites.

As you will see in the Asce7 Building Code there are two methods. Method 1 (section 6.4 simplified procedure) is a chart based format and is not used on this web site due to the fact method 2 (section analytical procedure) generates the same design pressures from a calculated basis. Method 2 (section has two limitations. The mean roof height is less than or equal to 60 ft and if the roof angles are less than or equal to 10 degrees the External Pressure Coefficients are reduced 10 percent. The method 2 (section analytical procedure) is used for mean roof heights greater than 60 ft.

A note about the Florida Building Code 2007, the FBC no longer gives you information to calculate the design pressures and refers you, in chapter 16 section 1603.1.4, to use the Asce7 code for your calculations. In chapter 35 (referenced standards) of the Florida Building code 2007, it specifically refers to use Asce7-05.

To get started select and enter your project information.

Wind speed =

From Figure 6-1

Importance Factor I=

Defined from Table 6-1, page 77

Building Exposure =

Defined from 6.5.6, page 25

Internal Pressure Coefficient =

From Table 6-5, page 47

Roof Angle =

From Figure 6-11, page 55

Kzt =

Kzt default = 1.00

Refer to section and figure 6-4 to determine the wind speed-up effect. See below for additional information about Kzt.

Kd =

Kd default = 0.85

Refer to Table 6-4, page 80

See below for additional information about the Kd factor.


Mean Roof Height = ft

Example 30'-6" is written as 30.5


Least Building width = ft

For determining Zone 5 dimension "a".

The following fields are optional and will show up on you printed page.

Project Name = optional

Company Name = optional

User Name = optional

E-mail = optional


A note about the Kzt factor: Kzt is a topographic effect factor to account for speed up over hills. Since I reside in Florida I use Kzt equals one and established that as the default value. Refer to your states Kzt values and adjust the value as required. I found a paper from the Florida International University stating few places in the state of Florida would warrant an escarpment factor greater than 1.0, therefore Kzt is unnecessary in the current endeavor. I found a great site showing the Kzt factors for Seattle, Washington from the Department of Planning and Development, their values range from 1.12 to 2. Refer to the links page for information.

A note about the Kd factor: Kd is a directionality factor. Over the years the Kd factor value has stirred up some controversy as to whether the value is 0.85 or should be one. I have set the default value to 0.85; if you are uncertain what value to use change the value to one for a worst case scenario. I found a good reference to this question at Engineering Express to support the Kd factor equals 0.85. Refer to the links page for information.

Please take a look at the material optimizer.
Click your back button to run the program again or select the link to Start Over

Thank you for using ASCE7-05 Windload Program.