Deck Posts and Railing using Curtain Walls in Architectural Desktop

Contents:
Overview ---- Body ---- Conclusion

1Overview
The Problem

It seems like everyone wants a porch or deck with posts and railing these days.  More expensive homes here in California tend to be on hillsides offering views of valleys, mountains, lakes or the Pacific Ocean so why wouldn't you want a deck for the grand viewing.  In Architectural Desktop the problem with creating the optimum solution for this type of design lies in the tools.  The Railing Object seems like the obvious choice but it was really designed for Stairs and though you can create some great deck railings, the Object's Properties and Style Settings are lacking when it comes to a more structural consideration.  The Column Structural Member Object may be good for columns and footings, you can even control spacing with a Column Grid, but this is a cumbersome option that offers nothing for railings.

In this article I will discuss how you can use a Curtain Wall Style to combine the need for Structural Column with Railings.  The primary reason I decided to explore the use of Curtain Walls for this type of design problem has more to do with the precise control I have over Post placement than anything else.  With Railings, for example, you cannot force the posts to be 8'-0" on center unless the total length is a factor of 8'-0".

2Body
Creating the Column Division

Create a Curtain Wall Style and name it something like "6x6 Deck Posts and Railing".  When you go to the Style Properties for this new Curtain Wall Style, you will find a variety of default settings that will be changed in this article.

Illustrated to the right I show that I renamed the default "Primary Grid" to "Posts" because that is a better description for what this Division will control.

Typically, the default "Primary Grid" is set to "Horizontal Division" and in this example I show that I am keeping that Element but changing the Cell Dimension to match the spacing I want for my posts (shown here as 8'-0").  I have also decided to use the Auto-Adjust Cells option and set the Cell Adjustment to "Shrink" for both ends.  Keep these settings in mind as you design your own post and railing system.

You can play with the Auto-Adjust Cells settings and see how they affect the type of work you do but remember that you can also change the Division Type to "Manual" for extremely precise spacing - useful when attempting to place posts in alignment with other architectural features.

Creating the Railing Division

Typically the default "Primary Grid", now named "Posts" has a Cell Assignment set to *Nested Grid* and in the illustration to the right I show that I have renamed the default "Secondary Grid" to "Railing".

The default "Secondary Grid" is usually set to "Vertical Division" and in this example I show that I am keeping that Element but changing the Division Type to "Manual" so I can set the heights for the bottom and top rails.

In the illustration to the right I show one Gridline at 36" From Grid Bottom and another Gridline at 3" From Grid Bottom.  Think of these values as centerlines for your rails so you may want different values depending on the thickness of each member.

In this example I am thinking of the bottom of the Curtain Wall as the top of the desk which will probably be drawn as a Slab Object.

 
Creating the Baluster Division

Now that the top and bottom rail positions have been defined, it is time to define the balusters.  In the illustration to the right I show that I set the "Default Cell Assignment" to "*Nested Grid*" and added a "New Cell Assignment" which I will discuss later.

Once I set the "Default Cell Assignment" to *Nested Grid* it automatically created a new Cell Division Name called "New Nested Grid".  I renamed this Cell Division to "Balusters" and set the Orientation to Vertical, Division Type to "Fixed Cell Dimension", Cell Dimension to 5" and Auto-Adjust Cells to Grow at both Ends.

If you know the dimension of your balusters and you want to stay code compliant, you may want to use a different Cell Dimension than the 5" I show; i.e., you don't want a 4" diameter sphere to be able to pass between the balusters.

My decision to use the Auto-Adjust Cells was not part of my initial design plan but after running some experiments on the completed post and railing solution, I found it necessary to use this feature to avoid having balusters end up inside or too close to the end posts.  I recommend that you run your own tests to create an optimum solution for your needs.
Creating Blank Space

In the discussion directly above I stated that I created a "New Cell Assignment" but did not elaborate on how or why it would be used.  By default, Curtain Wall Styles fill in all voids with a default Element that usually appears as glass (which makes sense for Curtain Walls) but for a Post and Railing solution, the void(s) should be not be filled in.

Illustrated to the right I show that I have jumped down to the Infills section and changed the "Default Infill" name to "Blank".  I set the Panel Thickness to 0" so it will effectively disappear.

Back on the Railing Division I assigned the "Blank" Infill to the New Cell Assignment and set the Location to "Bottom" and "Top".  The Balusters will are in the Middle Location and will automatically have this same "Blank" Infill assigned for the spaces in between each baluster because it was the default.

 

 

Creating the Balusters

After defining the Baluster Division, you can create the actual Balusters.  In the illustration to the right I show that I have jumped down to the Mullions section of this Curtain Wall Style and created three Mullion NamesBalusters, Bottom Rail and Top Rail.

In this example I have chosen to make my Balusters 2" Wide by 2" Deep just for simplicity.  Later I will discuss how to assign these to the Baluster Division.

In this example I also show that I have created a Bottom Rail with a Width of 1 1/2" by a Depth of 3 1/2" and a Top Rail with the same dimensions.  Later I will discuss how to assign these to the Railing Division

Once you have created the Baluster and Rails, you can return to the corresponding Divisions and Assign these as Mullions.  In the illustration, lower right, I show how I have returned to the Balusters Division and set the Default Mullion Assignment to "Balusters".

I have also returned to the Railing Division and set the Default Mullion Assignment to "Top Rail".  However, since I want to provide an option for a Bottom Rail with different dimensions or Profile, I show that I added a New Mullion Assignment and set it to "Bottom Rail" with a Location of "Bottom".

Creating the End Posts

When using a Curtain Wall Style as a Post and Railing system, think of the outer frame as the end posts but without the top and bottom horizontal members.

Illustrated to the right I show that I have jumped down to the Frames section of this Curtain Wall Style and created two Definitions that I named "6x6 End Post" and "6x6 Start Post".  The reason for a different Start and End post will be explained at the end of this article but you could get away with just one Definition if you prefer.

I set the Width and Depth for each Frame Definition to 5 1/2".  Under the Offsets section, I set the X value to one-half the Width (2 3/4") because I want to be able to draw my Post and Railing system based on the centers of the first and last post.  The other reason I set this value is because I want the Division between the posts to be from center-to-center on all of them; including the first and last.

Also under the Offsets section, I show that I have set the Start value to a negative 3'-0" (-3').  The reason for this is to demonstrate how you can account for posts that project below a deck and down to grade level.  Keep this option in mind.

Creating the Intermediate Posts

After creating the end posts, it is time to create the intermediate posts.  Illustrated to the right I show that I have jumped down to the Mullions section of this Curtain Wall Style and created a new Definition that I named "6x6 Intermediate Posts".

I set the Width and Depth for this Definition to 5 1/2" to match the end posts.  Under the Offsets section, I set Start value to match the negative 3'-0" (-3') I set for the end posts.  There is no need to adjust the X Offset because mullions are automatically based on the center line set by the Division values.

Once the Posts have been defined, they can be assigned to this custom Curtain Wall Style.  Illustrated to the right I show that I have returned to the Primary Division, Posts, and set the Default Frame Assignment to "6x6 Start Post" with a Location of "Left".  I also added a New Frame Assignment and set it to "6x6 End Post" with a Location of "Right".  For the intermediate posts, I used the Default Mullion Assignment and set it to "6x6 Intermediate Posts".

3Conclusion
For the more advanced: using the right and left Posts for Block Attachment.

In the discussion above I created a Frame Definition for a Right and a Left Post which were Assigned to the Primary Division with matching Location Settings.  The reason I created a separate Right and Left Post has to do with how Architectural Desktop's Curtain Wall Frame reads its Frame as a contiguous entity.

Illustrated to the right I show that under the Model Display Representation for this Curtain Wall Style, I have set an Override and used the "Other" tab to Add... a custom Block of a concrete pad.  Notice that I am only using the "Draw Custom Graphics" option and not the "Replace Graphics" option because I don't want to remove the Post, just add something to it.  For the "6x6 End Post" I can attach my Block to the Bottom of the Frame (renamed 6x6 End Post), but for the Start Post I have to attach the Block to Top of the Frame (renamed 6x6 Top Post) and then Mirror the Block in the Z-axis.  If I don't go through all of this tedious work, the pier block would end up on top of the Start Post.

I also added my pier pad Block to the Intermediate Posts using the same settings as those for the End Post.

When you start to go out on a limb with customization in Architectural Desktop it seems that you always get bitten by weird limitations.  In this case, as soon as you use the option to add a custom Display Component, you lose the ability to control the Component By Material under the Layer/Color/Linetype tab.  This means that you cannot assign a Material to the Posts.  In VizRender you can drop a Material on the Posts to remedy this problem but if you are not skilled at this type of work, you may not like this last bit of customization work.

 

 

Copyright 2007 ARCHIdigm. All rights reserved.