Open Bays
Overview
The Open Bay feature allows sections of a steel building to be left open, providing partial or full access along a wall or gable.
This is done by simply selecting the area you wish to open. Whether you are opening one bay or converting the entire building to a roof-only structure, these enhancements are all performed using the Open Bay feature.
When applying an opening to a side wall, always check the clearance height displayed in the design layout. Ensure this clearance height is adequate with the client before issuing the quote.
Why this is important
Enables flexibility in building design by creating open or semi-open sections.
Allows the addition of roof-only or partially enclosed structures.
Automatically adjusts engineering parameters to suit internal pressure coefficients.
Adding and deleting open bays
To add an open bay
Select the Open Bays tab.
Point the mouse to the desired bay location.
Click once to open the bay.
To delete an open bay
Right-click over the open bay and select Delete Open Bay.
Adjusting header sheet height
You can have only a portion of a bay open on a side wall.
For example, if your client wishes to reduce the opening clearance height from the ground up:
Right-click over the open bay.
Select Header Sheet Height.
Nominate the required clearance height.
Header sheets in open bays provide bracing value as determined by the program.
Setting header sheet measurements
From ground: Enter the clearance height required from the ground.
From gutter: Enter the length you want the sheeting to extend downward from the gutter.
Note:
You cannot apply sheeting only to the bottom portion of an open bay to create a horizontal gap.
Example:
If a client wants an open bay with wall sheeting from the gutter down for rain protection and specifies a 2.5 m clearance, you would:
Open the bay using the Open Bay feature.
Right-click on the open bay and select Nominate Height.
Enter 2.5 m from ground as the clearance height required.
Clearance height under open bays
Once applied, the design layout will display the clearance height of the open bay.
Note that the clearance height is less than the eave height because the eave purlin connection increases when an open bay is applied.
To increase the clearance height, you must increase the eave height of the main building.
Beam-overs (removing a column)
It is possible to remove a column between two open bays on a side wall.
To apply a beam-over:
Right-click on the column that needs removal.
SMS will automatically configure the engineering to suit the new design.
Important notes:
Beam-overs can only be applied between two bays — you cannot remove two consecutive columns.
The design layout will indicate which columns can be removed.
Beam-overs cannot be applied to adjacent columns on the opposite side wall.
Opening the gable end
You can open individual bays or the entire gable end wall.
To create a clear span:
Right-click on the end wall in the design layout and select the open option.
Note:
The building is measured from inside wall sheeting to inside wall sheeting.
When the client requests a specific clearance width, consider the side wall girts and columns.
Refer to the Material Specifications Sheet for more information.
Knee braces may affect clearance height — confirm via the Material Specifications Sheet.
When changing a fully enclosed building to an open building, SMS will automatically adjust the internal pressure coefficient as part of the engineering recalculation.
Gable infill sheeting
A gable infill is a panel of sheeting applied above the eave line up to the centre peak of the gable end wall.
To apply a gable infill:
Right-click on the gable end wall and select the infill option.
Note:
Before applying this feature, change the purlin type to Z purlins.
Tips, best practices & troubleshooting
Always verify clearance height with the client before finalising the quote.
Adjust eave height if additional clearance is required.
Avoid overlapping beam-overs on opposite side walls.
Ensure Z purlins are selected before applying gable infills.
Review structural bracing and knee brace requirements after modifying open sections.
Related resources
Personal Access Door (PA Doors)
Review & updates
Version history:
v1.0 – 19 April 2025
v2.0 – 6 October 2025
Article information
Category: Estimation View & Shed Design
Target audience: Estimators, SMS users, and design teams
Business owner:
Version: v2.0
Last reviewed: 6 October 2025