Discover the professional practice of reading and understanding building plans, with a focus on the significance of image numbers, sheet details, and differentiating between horizontal and vertical dimensions. This article dissects the components of a building section, explaining the importance of each part in an easily understandable manner.
Key Insights
- Building sections on plans are organized with lower image numbers at the top, increasing as you move down. This is due to the typical practice of stapling drawings on the left-hand side and opening from the right, making it easier for the viewer to follow the plan.
- Each sheet in a building plan has unique features including the sheet number, name, project number, and keynotes. Material legends and notes for the drawing are usually sheet-specific, showcasing different patterns for earth, sand, concrete, and gravel, among others.
- Building sections primarily highlight vertical dimensions, unlike floor plans which focus on horizontal dimensions. They are not meant to duplicate the dimensions seen in floor plans, but rather supplement them with vertical dimensions and datum information, which is also reflected in building elevations.
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Let's begin looking at our building sections, which are on sheet A4.1. If you look right here, you can see that it says image number one, sheet A4.1. Down here, image two, sheet A4.1. You'll see when we start working on the detail sheets, when we have multiple images on a sheet, it's very typical to start off with the lower numbers here, and as we go down, the numbers increase, that the image numbers will start at one, they'll go down to two, three, and four, and then images five and six will be over here on the left. The reason we do this is that typically drawings are stapled on the left-hand side, and people open the drawings from the right, and they open them to the left. So again, image numbers tend to be one up here and two over there.
So what we have going on is like before, we have the sheet number, the sheet name, we have the project number, who drew them, who checked, the revision dates, we have keynotes, and again, these keynotes tend to be sheet unique. You can see that right here, I'm showing some bubbled information and the delta for when I submitted the modification. I have my notes for this drawing, and I have my material legends, and again, the material legends tend to be unique for the sheet.
You can see that I'm showing a different pattern for earth, for sand, for concrete, and for gravel. I'm also showing a vapor barrier. Vapor barriers are typically something like a piece of plastic that keeps water from penetrating into the building.
When we were working on the floor plans, on the dimensions, you noticed that our dimensions were horizontal and vertical dimensions. Again, the floor plan is a horizontal slice through the building. Dimensions tend to be linear, again going horizontally or vertically.
When we go work on a building section, we are not calling out the horizontal dimensions that are reflected in the floor plan. Instead, we're showing out vertical dimensions that are relevant for the building section itself. If you look down over here, you can see that we're showing slab heights and different elevation callouts.
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This symbol right here is called a datum symbol, and so what we're doing is we're calling out datum dimensions, and if you look at the verticals, you can see that I'm calling out vertical dimensions between the floors. Again, we normally do not duplicate floor plan dimensions on building sections or on elevations. Rather, we include the datum information, and you can see that here I'm showing that the top of the parapet, which is the top of the wall, is at a vertical relative height of 30 some odd feet.
Again, I'm calling out the vertical dimensions with the datums. We will find that these same datums are on both the building elevations and on the building sections. Now, what's happening up here is that I have an enlarged detail for the top of the parapet.
So, if I want to see this enlarged detail, I would go to image 6 on sheet D7.4 to see that image. If I want to see the detail of what's happening over here, I would go look at image 1 on sheet D7.1. So, again, here's the building section. You can see that, once again, I have callouts that are saying if I want to see more information about what's here, that I need to go look at this detail on this page to see that information.
