Mar 05

How To Design An Efficient Solution on the Roof Plan Vignette

On the Roof Plan Vignette of the ARE, designing an efficient solution will be one of the critical factors in determining if you pass or fail that exam section.

Like most ARE vignette sections, learning how to design the most efficient solution possible is essential because there are multiple solutions possible.

Sure, anyone could design a solution that meets all of the requirements of the Program, but what NCARB is looking for in your solution is an EFFICIENT design that still meets all programmatic requirements.

This is true on most vignette sections (with a few exceptions), but especially true on the Roof Plan vignette.

Roof Plan Vignette

The basic concept of the Roof Plan vignette is to take a given floor plan and then design a 2-level roof plan that satisfies all the requirements given in the code.


There are a number of smaller elements that you’ll need to include in your solution such as skylights, MEP units, gutters, downspouts etc. These elements are simple and easy to add. They don’t require too much “design” work.

The bulk of your design work in this vignette is with determining the slope, orientation, and heights of your roof.

This is where designing an efficient solution comes in to play!

Start From The Bottom

The easiest way to figure out your roof heights in an efficient manner is to start at the bottom and work your way up. Like I mentioned above, your solution will most likely be a lower roof level and then a double-height space that will require a higher roof.

Start by determining the minimum ceiling height of the lower roof area. This is given to you in the Program.

  • (In the NCARB Sample Vignette, the ceiling height is 8′-0″)

After that, determine the thickness of the roof structure. Again, this is given to you in the Program.

  • (In the NCARB Sample Vignette, the roof structure is 18″ thick)

Add these 2 numbers together and you’ve determined the elevation of your Lower Roof!

  • (Again, in the case of the NCARB Sample Vignette, your low roof elevation should be set at 9′-6″)

There’s no reason to add any extra height than just the ceiling height and the roof structure. Candidates get into trouble because they will set their roof elevation higher than the minimum.

This is considered over-designing! It’s not a fatal mistake, but enough instances of over-designing can lead to a failed exam.

It’s important to design to the minimums allowed by the Program and no more!

Use Minimum Roof Slopes – Low Roof

Now that you’re lower roof slope is determined in the Roof Plan vignette, you need to set your roof slope.

This is easy.

In the vignette software, you have the ability to set the orientation and slope of your roof.

The orientation should be set depending on which way you’re pitching your roof depending on your background plans.

To determine your slope, check the Program because a range of slopes is given to you.

BE CAREFUL though! The Program lists different slopes for the low roof vs the high roof so make sure you look at the slopes for the low roof at this point.

Pick the MINIMUM slope allowed and use this!

  • (In the NCARB Sample Vignette, the low roof slope can be a low as 2:12)

By picking the minimum slope allowed for the roof, you’re essentially designing the most efficient roof for this section of the roof.

There’s no reason to go with any higher of a roof pitch.

Set the High Roof Elevation

After you’ve drawn in and set the elevations of your low roof, it’s time to do the same to the high roof.

Determining the elevation of the high roof is similar to the low roof but there are a few more elements to factor in, like the clerestory window!

The Program will typically require you to place a clerestory window in one of the walls of the high roof. It’s recommended that you design your high roof so that the clerestory window is on the low side of that roof (not the high side or the gable side).

With that in mind, you need to determine what the highest point of the low roof is and use that as your starting point.

22_Place Clerestory

Since you set your slope of the low roof, the software automatically determines the roof heights at all corners of the roof. Click around until you’re able to determine what the HIGHEST elevation of the low roof is along the wall that the clerestory window needs to be in.

  • (In the NCARB Practice Vignette, determine the highest point of the low roof along the west wall of the Exhibition Room, since that’s where the clerestory needs to be)

This is your starting point, similar to the minimum ceiling height when figuring out the low roof.

After that, figure in the clerestory height and the roof thickness of the higher roof. These are both given to you in the Program.

  • (In the NCARB Practice Vignette, the high point of the low roof is 12′-6″ plus the clerestory height of 24″ and then the thickness of the roof structure is 18″ equaling a High Roof Elevation of 16′-0″).

Again, there’s no reason to add in any extra height. Using these minimums by determining the high point of the low roof and figuring in thicknesses given in the Program, you’ve designed the most efficient solution possible.

Use Minimum Roof Slopes – High Roof

Just like you did on the low roof, set your high roof slope to the MINIUM allowed by the Program.

Make sure you read the Program though because the minimum roof slope for the high roof is usually different than the low roof.

  • (In the NCARB Practice Vignette, the minimum high roof slope is 6:12)

Again, there’s no reason to set this slope any higher than the minimum allowed by the Program.

Final Thoughts

As I’ve mentioned above, designing in the most efficient manner possible is essential when it comes to passing the Roof Plan vignette.

There are a lot of factors to consider, but most of these are given to you in the Program so the key is to make sure you’re using the correct numbers and not exceeding them.

Keep in mind that over-designing one area probably won’t be enough to fail this section but if you over-design in enough areas, you may fail.

I can’t stress this enough, just design to the MINIMUM allowed by the Program and you’ll be just fine.

If you’d like a closer look at some tips and tricks of the Roof Plan Vignette, please see the Building Design & Construction Vignette Guide, part of the ARE Advisor Vignette Series.

This guide will give you a step-by-step breakdown of the BDCS Vignettes (Ramp/Accessibility, Stair Design and Roof Plan Vignettes) and what you can expect. The guide uses the examples provided by NCARB so you can follow along using the NCARB practice software.

Since a fatal error on a vignette will cause you to fail an entire ARE exam division, I certainly recommend taking your time to understand exactly what you need to do to pass the vignette section. In my opinion, the vignette sections of each exam are the most important parts since one mistake can cost you the entire section.