Expert: Richard Taylor, AIA - 2/12/2008

Question
Is there a specific pitch or range of pitches for mansard roofs?  We, Yankeetown planning commission, would like to specify no flat roofs in commercial zones unless enclosed by a false mansard type roof.  We would like to specify the pitch for these false mansard fronts.  Is a range from 18:12 to 36:12 reasonable?  What would you suggest?  Thank you for your time and assistance.

Answer
Hi Chris - thanks for your question!

36:12 is practically vertical; there's really no need to set a top-end limit to the pitch.

Is your goal to limit architectural styles?  I'm wondering because a "mansard" roof is almost always associated with Second Empire style - which isn't a popular style (at least not around here!).  Limiting roof pitches to only the very steep will make it difficult to do anything but "Munsters" designs.

From my experience on both sides of the table of many, many review boards over the years, I'd suggest you do a less "prescriptive" code and think more about what you can do to encourage good design - I assume that's your ultimate goal.  You could for example, say that all rooftop equipment must be screened from view from the ground, and/or that only certain roof materials can be visible (you could exclude ballasted roofs, rubber roofs, etc.).  That way you get what you want (no visible roofing) and still let owners and their architects explore ways to do interesting architecture that fits the area.

Too often, citizen planning boards with the right intentions go about it the wrong way.  I'd guess that there are lots of talented architects around Yankeetown that can do great stuff if you encourage them to. The communities with the best architecture and the best-preserved architectural heritage are the ones who let their best architects explore contextual design options with little hinderences.

I'm reminded of a private community in Scottsdale, AZ that has a very detailed and very comprehensive design guideline document; it's all about the community's goals - it says realtively little about actual materials, colors, or procedures.  The result is a large community of very interesting buildings that are very different - and yet they all work together, because the code encourages quality without specifying how to achieve it.  That's left up to the designers.  It compares very favorably to more-restrictive developments where everything looks exactly the same - because the code requires it.

On the other hand there's a communitiy in Ohio where every building MUST be Georgian Colonial - imagine a development of 5,000 red brick homes...and a red brick Starbucks...and red brick gas stations...and...you get the idea!

Regulating design with specifications is a slippery slope - it almost always results in mediocrity.  Find ways to encourage good design and you'll do better in the long run!

Hope this helps,

Richard Taylor, AIA
www.rtastudio.com
www.rtaplans.com