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Last Updated: 16 February 2021

2.3.8- Open a hole in the First floor roof slab for the stair - Add Railing

A.- Interference Condition

To operate the stair, you need to open a hole in the roof slab, long enough for someone going up not to bump his head, as shown in Fig.2.2.8.3.
To open a hole in the roof slab of the first floor,  you will add an interference condition between the stair and the slab.

With the interference condition, you can Add or Subtract other objects to a slab. The Subtract option removes the mass element from the slab.

Stair that is applied as interference condition in roof slab, can be edited like any other object using grips, or on properties palette. If you edit stair, and change width, height, headroom height, etc, the roof slab updates accordingly.

When you add an inerference condition between the stair and the roof slab, a box is cut around the stair, based on the stair's specified headroom height and side clearances.

The length of the hole is set in the Properties Palette (Fig. 2.3.8.1) of the stair, in the category Advanced > Interference > Headroom height.
The Headroom height defines the clear height between beam and slab at the edge of the hole (Fig.2.3.8.3).

To open a hole in the first floor roof slab for the stair:

• For your own convenience hide the wall (mg), and the openings of these wall, to have a better 3d view of stair and slab (Fig.2.3.8.1).
• Double-click the stair to open the properties palette (Fig.2.3.8.1).
• Click the Design tab, expand Advanced, and expand Interference.
• Specify the height above the threads for the interference condition. At this stair, for Headroom height enter the value 2.10 (as shown in section at Fig.2.3.8.3).
• Click Esc, to remove the selection of stair.
• Select the slab, on the roof of the basement, to intersect.
  On Ribbon > click Slab tab > on Modify panel select Interferencee Condition drop-down > and then select Add icon . 
• At the prompt: Select Object to Add: select the stair, and press Enter.
• At the prompt: Enter Shrinkwrap effect: select Subtractive and press ENTER.
• Press the ENTER button again to end the command execution.

The result is as shown in Fig. 2.3.8.2.

To remove the hole in the basement roof slab:

• Select the slab, in the roof of the basement, from which to remove the interference condition.
• On Ribbon > click Slab tab > on Modify panel select Interferencee Condition drop-down > and then select Remove icon . 
• At the prompt: Select Object to Remove: select the stair, and press Enter.
• Press Esc to end the command execution.

Add the Stair Railing

Railings are objects that interact with stairs and you can add railings to existing stairs, or freestanding railings.
AutoCAD Architecture provides the tools that let you place railings using a railing tool with specific predefined properties. You can use the default settings of the tool or you can change the properties.

• To design the railing of this stair you will use from the Tool Palette - Design (Fig. 2.3.8.5), the style of railing called Guardrail - Pipe. If there is not this style of railing in the Tool Palette- Design, you will get it from:
  Ribbon > Tools  > and select Content Browser. You will import this from Content Browser in to your Tool Palette-design.
• To do this: On the Content Browser which will open, select > Design Tool Catalog > Stairs and Railing > Stairs > select the Guardrail - Pipe railing icon, and drag it with your mouse on the Design Tools Palettes.
  
  

To design the railing:

• Open the Design Tool Palette, select the railing style Guardrail - Pipe Fig.2.3.8.5), the Properties Palette of this railing style will open (Fig. 2.3.8.6) where you can edit the values according your needs.
• On the Properties Palette (Fig. 2.3.8.6), in category Location make sure that attached is set to Stair, Automatic Placement is set to Yes., and for Side offset set 0.05.
• At the command prompt Select a stair or [….]: select a point on the side (P₂P₃P₄P₅) of the stair and press Enter.
• The railing of the Stairs have been created as shown in (Fig. 2.3.8.7).

Add a Freestanding Railing around the hole

You will add a freestanding railing, for protection, around the hole you opened for the stair.

Draw the polylines (r1r2r3r4), and (r5r6), on the top of the slab hole, and in a distance 0.05 from tha edges of the hole, as shown in Fig.2.3.8.8, that you will use to create the railing.

You will use the railing style Guardrail – Pipe + Rod Horiz., and after drawing the railing, you can edit it's style.

To design the railing:

• Open the Design Tool Palette > select the railing style Guardrail - Pipe (Fig.2.3.8.5), right-click on it > Apply Tool Properties To > select Polyline and select the polylines  (r1r2r3r4), and (r5r6), (Fig. 2.3.8.8), and press Enter.
• The railing of the Stairs have been created as shown in (Fig. 2.3.8.8).

Change the Properties of a Railing object

You can change dimension settings on the properties palette of the railing object, that you created.

To be able to do this, you have to select "Allow each Railing to vary' on the Railing Style Manager. It specifies whether that properties of this railing style can be overridden for individual railing objects.

To change the properties of the railing that you created for the stair:

1. Select the railing of the stair you want to edit (it's style is Guadrail Pipe + Rod Horiz).
2. On Ribbon, click Railing tab > General panel > Edit Style drop-down > Edit Style 
3. On the Properties Palette, click the setting for Rail Location, the worksheet Rail Location will open.
4. If you notice, that the settings in the Rail Locations worksheet is read-only, it means that the rail locations have been set in the style, and cannot be overriden here.
   To deal with this issue:
5. Select the railing of the stair you want to change properties > on ribbon click Railing tab > General panel > Edit Style drop-down > Railing Styles > select Guadrail Pipe + Rod Horiz
   
6. On the Style Manager that will open click tab Rail Locations, and select Allow Each Railing to Vary. (Fig.2.3.8.9).
7. Click tab Post Locations, select Allow Each Railing to Vary, and click OK.
   It specifies whether that properties of this railing style can be overridden for individual railing objects.

• Go back, select the railing of the stair you want to edit, and on it's Properties Palette, click the Rail Locations tab, and on the work sheet that will open:
• Set for Guardrail Horizontal Height = 0.900, Sloping Height = 0.900, set for Bottomdrail Horizontal Height = 0.175, Sloping Height = 0.175, set Number of Rails = 4, and Spacing of Rails = 0.175, and click OK.
• The Properties of the Railing changed. Note that changes to railing properties, do not affect existing railings of this style, unless you change each Railing object separtly.

Create a 3d Conceptual view

• Click on the corner WS of View Cube icon  to get a 3D isometric view of your project or select the 'Top' from the View Cube to get a floor plan of your project.
• You can apply Conceptual view in your plan to have a more artistic view (Fig. 2.3.8.10). To do this:
• On Ribbon > click on View tab > select Visual panel > select Conceptual
• The result is as shown in Fig. 2.3.8.10.

Save this drawing under the name h21190_firstFloor in the folder customDwg\firstFloor you have created. It's full path will be:
C:\ACA\myProjects\house21_190\customDrawings\firstFloor\h21190_firstFloor.
You will use this drawing in chapter 5, to create the construct drawings of the first floor.

The next lesson is 2.4. Create the Roof and Attic.