A Joist Direction Line defines the direction joists are laid out. Every floor platform can have its own joist direction. If a direction line is not specified, the joists are run the way that makes them shortest.
Select Build> Framing> Joist Direction and draw a joist direction line as you would draw a CAD line.
The text along the joist direction line states the joist size and spacing for the platform. Unless the individual joist direction line is edited, these values reflect the settings specified on the appropriate floor tab of the Build Framing dialog.
The Joist Direction Line controls the joist depth and spacing information for the floor or ceiling platform containing it.
To change this information, click a joist direction line to select it and click the Open Object edit button. The Joist Direction Specification dialog opens.
The Joist Direction Line changes the joist specification for the entire platform, but does not affect the settings in the Build Framing dialog. Settings in the Joist Direction Specification dialog affect subsequently produced framing only in the platform that contains the selected joist direction.
Note: For the Depth value to take effect, Rebuild Walls/Floors/Ceilings to regenerate the platform with the proper thickness.
Two Joist Direction Lines, one on either side of a Bearing Line, can split a platform into two for the purpose of defining different framing specifications for each area.
A less common application would be to use a single joist direction line across two separate platforms in order to define a single framing specification for both platforms. This is illustrated by the following example:
A 1 1/2 story house is shown in cross section in the diagram.
Normally, the program produces a floor platform under the second floor living area and a ceiling platform under the eave area, which is not a room area.
This is fine if the first floor has supporting walls or a large beam under the second floor kneewalls. If it does not, the floor platform should extend to the first floor outside supporting walls, replacing the ceiling joists.
Use joist direction lines to define separate floor platforms under the second floor living area and ceiling platforms under the attic eave area or one continuous framed platform across both spaces.
To connect a floor and ceiling platform into a single platform, draw a Joist Direction Line that crosses the boundary between them.
Following is a diagram of the original framing with the new Joist Direction Line spanning the knee wall area.
(Note: Several framing members have been deleted to make the new Joist Direction Line more visible.)
Although the framing of the 2nd floor platform is being edited here, the joist direction is drawn on the first floor. In Chief Architect, floor platform framing displays with the floor below, so its joist direction information must be placed there, as well.
You must click the Rebuild Walls/ Floors/ Ceilings button after placing a Joist Direction Line before the changes take effect.
Next, rebuild the floor framing for the second floor and the ceiling framing for the first floor. The floor framing now spans into the area which was previously framed using ceiling joists.
The 3D view of the framing also reflects the change.