THE PROBLEM WITH BUILDING HEIGHT RESTRICTIONS IN ZONING CODES

Height_restriction_diagram

This post is about building height restrictions that are required by zoning codes, and are enforced by building officials and architectural review committees of historic districts, specifically height restrictions that are in feet, not number of stories.  This becomes problematic for the traditional or classical designer.

 

The Vieux Carre in New Orleans is one such district with zoning codes that restrict the heights of buildings.  The zoning code and architectural guidelines indicate that buildings are limited to 50 feet, and then “building height” is defined as being measured from grade to the top of a parapet if the building has a flat roof, to the midpoint of the slope of the roof for buildings with gable or hipped roofs, and to the top ridge of buildings with a mansard roof.  The definitions further indicate that vertical elements such as chimneys, cupolas, finials, etc. are not considered when determining a building’s height.  The guidelines further indicate that in addition to the 50 foot height restriction, no building shall be higher than the tallest existing building on the block face of the subject building.

 

The intent of the height restrictions is to prevent the construction of buildings that are out of scale with the existing historic buildings.  The problem is they were written by planners unfamiliar with the design of traditional buildings.  Ironically, the architects and builders of the historic buildings that exist within the district did not have a 50 foot height limitation imposed on them when they created the buildings that comprise the district.  Historically, a building’s height was limited by practical concerns such as how many flights of stairs a person was willing to ascend to get to the upper most floor, as well as the building technology of the time.

 

When designing a building’s façade, a number of issues come into play.  The proportions of openings and the heights and elevations of cornices, water tables and impost bands are all coordinated so that the overall height and width of the façade, or half of the façade is related to all the smaller elements that comprise the façade.  If the building has a classical cornice, the classical order that is assigned to the façade will determine the heights of many of the façade’s components. 

 

What happens instead is the façade’s vertical dimensions are manipulated until the façade is in compliance with the guidelines.  For example, the floor-to-floor heights are reduced slightly, and then the window heights are each reduced, and then the spandrel between upper floor windows and lower floor windows are reduced.  Then the cornice is lowered so that it is right at the head of the upper floor windows, and the parapet is reduced.  The original façade design may have architectural or sculptural elements that extend above the parapet line to animate the façade, or perhaps the center bays has a parapet that is purposely higher than the outer bays to give a stronger hierarchy to the composition.  With a height restriction imposed on the designer, it becomes difficult to justify these elements that would extend up in violation.

 

The façade design before it is compromised may be over the height restriction by 24 to 30 inches, a small amount in the overall scheme of things, but members of the architectural review committee and concerned individuals from neighborhood groups and preservation advocates view the non conforming façade as one that is out of scale with the neighboring buildings.  Good proportions are ignored when reviewing the design.  It is an even worse prospect when you have to be less higher that the tallest building on the block face.

 

On the other hand, a 4 story building could be built with 8 foot floor-to-ceiling heights, and it would be in full compliance with the height restrictions.  The proportions of this façade would look even stranger sited next to the neighboring historic buildings.

 

The height restrictions get complicated when a sloped roof is part of the design.  What if the roof has dormers?  Is the height still measured to the midpoint of the slope?  What if there are many dormers that are close together, or one large shed dormer?  Does the midpoint of the roof slope still apply?  What if the roof has a normal slope at the front and back or perimeter, but is flat in the center, a sort of truncated gable or hip.  Would that be treated as a mansard roof, or should it be treated like a gable or hipped roof?  What if I designed a 100 foot tall building in the form of a pyramid?  Wouldn’t that comply with the height restriction since the exterior walls of a pyramid is essentially the roof, and the height measured to the midpoint of the slope would be right at 50 feet?

 

I have attached a drawing that I have prepared that demonstrates this issue.  The drawing depicts three Neoclassical townhouse facades.  The facades are similar to what may be found in a typical urban historic district.  The façade on the far left is a well proportioned façade, but unfortunately it exceeds the height restriction by 5 feet.  (Probably no one would have known had I not put that dimension on the drawing.)  The façade just to the right is essentially the same façade design except that it is manipulated to conform to the 50 foot height restriction.  Whatever proportions that were established in the first façade exercise are lost in this façade.  Finally, on the far right side is a façade design with 8 foot floor-to-floor heights, that completely sacrifices proportions in order to gain the greatest amount of floor area.  The sloped roof gives way to a flat roof with a parapet.  The first façade design, the one that was properly proportioned, would not be allowed because of its height.  The other two façade designs could potentially be approved, unless the members of the architectural review committee become aware of the complete lack of proportions demonstrated in the third façade design.

 

The conclusion is this:  The height restriction should be presented as a minimum number of stories; it is that simple.  For the Vieux Carre, the height limitations should be no more than 3 stories in most areas, although some areas can be increased to 4 stories high and other areas should be no more than 2 stories high.  This would not only simplify the design and review process, but it would also have the benefit of disallowing buildings that forsake good proportions for maximum floor area.  There also would be no need to worry about chimneys, cupolas, parapets, or midpoint of roof slopes.  If the height restriction would say “no more than 3 stories” and a 4 story project is submitted, it would be rejected; if the project had 3 stories then it could be approved.

 

Now can we discuss how to make the façade more beautiful, and not just how to shorten it? 

 

 

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