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Mar 28

UDO ENO/TNO

Posted on March 28, 2018 at 2:08 PM by Vivienne Uccello

Background
map with marked districts and zoningManhattan was incorporated in 1857. Like many other new towns at that time, it was platted. Meaning the layout, size, and names of the streets were predetermined, the land within the confines of those streets were divided, and certain areas were set aside for schools, parks, markets, and public squares. 

Everything included in the original town plat was also within city limits. This created ease for the transaction of land, the provision of utilities, and provided a framework for the city’s development into the future. For the better part of Manhattan’s first 100 years, the city stayed snugly within the boundaries of this original plat. It wasn’t until after the Second World War that the city broke free from its crib and started toddling around in the hills of the western frontier. To this day, it is very easy to see where the original city plat was. If you look at any map of Manhattan, you’ll see a distinctive grid pattern to the streets around areas like Downtown, Aggieville, and everything in between. This gridded area generally marks the original town plat and original city limits.  

The TNO 

6The Traditional Neighborhood Overlay (TNO) zoning district generally spans the lower-density residential areas of the original town plat. The TNO is a zoning overlay district created by the city in 2003 to regulate how new homes and substantial modifications to homes in the older part of town are designed and to conserve the existing housing stock. 

photo of historic home in ManhattanThis area of town and its individual buildings are special to our community and their conservation is a high priority. These neighborhoods are full of character and packed with history that links us to our past. There are home to diverse examples of architectural styles throughout the area built since 1850 including Victorian, Vernacular, Tudor, Romanesque Revival, Queen Anne, Prairie, Neo Classical, National Folk, Italianate, Gothic Revival, Craftsman, Colonial, and many more!

photo of historic home in ManhattanUnfortunately, not all of them will be preserved. Occasionally, houses will be demolished due to degradation, high costs of rehabilitation, or redevelopment opportunity. This is just a part of life. And when this does happen, it’s important that what replaces it be compatible with its surroundings. This is one function of the TNO. Another is to address how older development in Manhattan relates to modern zoning code. Because by today’s standards, these properties in the older part of town are, well… weird.

photo of historic home in ManhattanMany of these homes would not meet our modern zoning standards because they are too close to the street, too close to their neighboring property, built on irregular lots, too big, etc. And these aren’t necessarily bad things. It’s just how these homes were designed and altered long ago, at a time when zoning was very unrestrictive, or in many cases, before zoning even existed! And these are things that give neighborhoods character and mark our history.

But properties not meeting zoning regulations can cause other problems. In city terms, these properties are called “non-conforming”. But if they were built or altered before such regulations existed, they are considered to be “grandfathered”. While grandfathered structures can continue to exist and operate indefinitely, their non-conforming status can often be a hassle for property owners when they want to rehab, modify, or make improvements to their homes. But non-conformities on its own is a topic for another time and we will get to that in a future posting. 
So the TNO serves two major purposes, to encourage compatible in-fill development and to deal with the uniqueness of the existing building stock. 
It does in many ways, a few of which include…
  1. Allowing homes to be built closer to the street.
  2. Requiring parking behind or to the side of a house and utilizing alley access. 
  3. Requiring garages to be further back from the house.
  4. Requiring a minimum amount of windows.
  5. Requiring a certain roof pitch. 
  6. Requiring a roof overhang. 
  7. Requiring a door on the primary building façade.
A quick walk through one of the older neighborhoods, and you notice the majority of existing homes meet these regulations. That’s because the regulations are built around them, taking their characteristics and codifying them. After 15 years of the TNO’s existence, we can start to see how things are going. We noticed buildings constructed since 2003 weren’t really meeting the spirit of the regulations. Moreover, it is clear that in many ways, the TNO regulations are still not entirely reflective of the existing environment. That is, there are many homes still considered non-conforming due to their site layout. These aren’t going away anytime soon, and in some cases, it is putting an unnecessary burden on homeowners.

Advances in technology since 2003 have allowed us to conduct quicker and more comprehensive assessments of these regulations pertaining to the TNO. Specifically, aerial surveys through mapping software allow us to get better statistical data about how homes were built in the older part of town; how close they were built from the property line, how much of the lot they cover, building dimensions, lot sizes, etc. With this information, we are able to hone in on adjustments to the regulations to better fit the character of the area. This could also bring more homes into conformance, which could remove the burden of requiring property owners to get special exceptions when they wish to make improvements and investments to their homes. 

UDO
The UDO process gives us a chance to implement these new regulations pertaining to the TNO. But now we have to call it the Established Neighborhood Overlay (ENO) because the TNO through the UDO has undergone a name change. So bear with me here.

Site Layout
One thing we’re looking at is changes to the regulations pertaining to the site layout of a property. Specifically, the front and side setbacks, or how close to certain property lines a house can be built. The setback of houses from the front property line varies greatly throughout the ENO. In some cases, houses are a close as 0 feet and as far back as 60 feet. So it’s tough to make a call on what the standard should be and what would be considered “compatible” because it varies greatly from block to block and lot to lot. You could widen the range, but that could mean less compatibility. One possibility is customizing setback requirements by looking at existing houses surrounding a property. That is to say, calculating the average front setback of houses on the same block and making that the requirement for new construction, with some degree of allowed variation. For example, a block with say eight houses each setback 10, 8, 20, 11, 13, 25, 16, 15, and 18 feet could have a requirement for a new house on that block to be setback 17 feet plus or minus 5 feet.
3
 Now that’s front setbacks. Side setbacks are a different story.

graph of ENO setback sample with textAcross the board, the UDO introduces the concept of a “street-side” lot line. Simply put, lots on street corners are currently considered to have two front lot property lines despite the fact that there is functionally only one. This puts unnecessary constraints on corner lots throughout town, but especially in the ENO area due to its smaller lots. In fact, after sampling 100 corner lots throughout the ENO, we found that only 34% of them actually met the current requirement of 14 feet. Recognizing a street-side gives corner lot properties one true front setback, and one street-side setback. This number can be adjusted to better reflect reality. For instance, lowering the requirement to 8 feet would make 79% of the 100 sampled corner lots conforming while allowing new development to better match the existing.

Building Design
As far as the design of the homes, the UDO proposes a few additions to the existing regulations already in place with the TNO. The major ones address porch design, foundation materials, and street trees.

color photo of street with historic homesSince many of the homes in the ENO have porches, the UDO proposes accommodations to encourage their continued existence and their integration into new buildings by discounting the extension of a porch from the front yard setback requirement by about four feet. But while front porches are a nice feature and many of the older homes have them, it is not always an appropriate design feature for each architectural style. We don’t want to force people to have porches, but if they are to be built, we feel they should be functional and more than just an at-grade concrete pad with an overhang. One way of doing this is by requiring a minimum depth to porches and requiring them to be elevated. 

Most older homes in the ENO area, regardless of having a basement, have a visible foundation of a material different from the cladding of the house. Without this, a new home creates a low-slung look incompatible with the more vertical-oriented housing stock. A way to address this is by requiring a visible masonry foundation to new buildings.

We also recognize that trees are an important element to the character of the older parts of town that also provide immense environmental benefits. Many of these trees are easily over 100 years old and may not be around much longer. One proposal includes requiring trees be replaced so that there be a minimum number of trees adjacent to every property. This will aid in maintaining the tree canopy over time.

In Closing
There are a number of other regulations that could be implemented to make the design of new houses in the old part of town as compatible as possible. However, regulating buildings down to that level of detail is tricky and can inhibit autonomy of creative design. And we don’t necessarily want new buildings to insincerely “look old”. There is a balance of conserving the character of a neighborhood and allowing Manhattanites to design, build, and reinvest in unique homes they can be proud of in an older part of town. We hope to make this balance work.