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Saturday, July 1, 2017

Zoning Conflict & Opportunity

This is an attempt to understand the relationship of individual residential zoning regulations, the reasons why they often conflict to produce ambiguous shelter design leadership, and their improvement potential.

NOTE: I suggest printing this essay so you can place the tables next to the text for reference. Tables 1-3 document the conflict. Tables 4-7 are forecast models that present an algorithmic alternative. They are part of a comprehensive portfolio implied by Table 8, and eliminate conflict by automatically correlating independent regulations to reveal their combined implications. They represent the formation of a new leadership language that can lead a response to the issue of shelter for the activities of growing populations within a Built Domain that is geographically limited to protect their source of life, and is designed to protect their quality of life. The models represent one small step toward the absolutely essential goal of symbiotic survival. This is a document you must be prepared to study. It is not meant to be easy reading on the editorial page. It is meant to stimulate your interest in a new science - the Science of City Design.


Table 1 is a collection of residential zoning regulations distributed through the chapters of one zoning ordinance. Lines 14-29 apply to single family residential lots. Lines 31-91 are written for multi-family buildings, but also permit 1-4 family housing.

Minimum lot areas per zone are noted in column F. Building height regulations are noted in columns C-E. Maximum net densities are noted in column H. Lot width, depth, and setback requirements are noted in columns J-P. Parking requirements are noted in column Q.

None of these requirements are correlated. Each is independent and their combination has often produced conflict and contradiction that has defeated consistent design leadership. The dilemma is most easily explained by asking one question:

1)      Is it possible to achieve the net densities permitted in column H given all of the remaining independent requirements on any given line of Table 1?

Table 2 lays the ground work for an answer by calculating the implications of the zoning requirements in Table 1. Column HH gives the impression that the total gross building area potential for each zone is more than adequate. Column JJ shows that unpaved open space is a quantity that remains after all impervious cover topics are subtracted. It is not a requirement. It is a left-over quantity and cell JJ14 reveals a typical contradiction. The 3 acre R1 zone is intended to be the lowest density zone in the city; but when the independent line item requirements in Table 1 are analyzed, cell KK14 shows that they permit the highest percentages of two-dimensional building and pavement cover (impervious cover) in the community. This means that the lowest density is permitted to produce the greatest intensity.

The collection of requirements on line 14 of Table 1 also permit the greatest amount of three-dimensional gross building area as shown in cell HH14 of Table 2. Homes in the R1 zone are expected to be larger; but the maximum 158,610 sq. ft. shown in cell HH14 is far greater than needed for a single family detached residential home and contradicts the low density intent. Column JJ in Table 2 also shows that total left-over yard areas increase as density increases. This exposes another contradiction of expectations.

Column KK also reveals a more dangerous permitted condition. A residential storm sewer is often designed to accommodate the runoff from 30% impervious cover, but the actual percentages are often omitted from the public record. The percentage reduces initial pipe size and construction cost, but may not be correlated with zoning requirements that govern site plan preparation for building cover, pavement, and yard area quantities. Column KK in Table 2 shows that all permitted site plan impervious cover percentages in the column exceed 30%. Problems can begin when storm sewer design capacity percentages are not correlated with zoning ordinance regulations and recorded on approved plats. When permitted impervious cover excesses multiply along branch and trunk sewer lines with limited storm water capacity, flooding becomes inevitable and continues until a city can afford to construct relief sewers. In other words, the impervious cover percentage limits permitted for site plans in column KK should not exceed the design capacity of the storm sewer system present, planned, or permitted.

Table 3 measures the implications of Tables 1 and 2. The underlying question is the meaning of the measurements. For instance, the most obvious implausibility is on line 14. It pertains to the low density R1 zone, but permits some of the greatest shelter capacity (SFAC), intensity (INT), intrusion (INTR), and dominance (DOM) measurements in the table because of the zoning regulations in Table 1. This is a classic example of inadequate or nonexistent correlation that can occur between zoning regulations and city design results.

The measurements in Table 3 imply two additional questions:

2)      What measurements and percentages are desirable?

3)      How can regulations be correlated to avoid leadership contradictions?

I won’t attempt to answer Question (2). It will require site plan measurements and evaluation of hundreds, if not thousands, of existing site plans and building mass relationships before conclusions can be reached with the credibility required for public acceptance. When accepted, these conclusions will establish desirable, correlated parameters with the potential to lead the design and construction of shelter for the activities of growing populations within a geographically limited Built Domain. This will protect their quality and source of life – The Natural Domain.

Correlation is the objective of Table 4 and the answer to Question 3. Cell F3 defines the actual land area involved for this example. Cell F12 defines the shelter area available for “improvement” in cells F12-G12 after the percentages entered in the boxes of the Land Module produce quantities that are subtracted. (Any value entered in a box within the table is a variable that may be changed to explore options.)

Cells F15 through F19 define the design standards being tested. Line 23 introduces additional design decisions that apply to the proposal.

Line 38 calculates the implications of all design values entered in the boxes of the Land and Shelter Modules. Line 43 presents these calculations. The impervious cover value representing the sum of these building and pavement cover decisions is presented in cell J48. The bonus room above the garage is added in cellK38. Garage and accessory building areas are added in cell L38 to produce total building area (TBA) in cell L38. All of these values are presented on line 43.

Cells A53 to A74 contain unpaved open space percentage options. The shelter area density that can be achieved in column F of the Density Module is a function of the average impervious cover per dwelling unit value (AVGIMPD) presented in cell J43 and the unpaved open space per dwelling unit value (UOSD) chosen in column A of the Density Module. (One minus the UOSD% in column A should coincide with the storm sewer capacity present, planned, or permitted.)

The density results in cells F53 to F74 serve to explain that density is not a leadership tool. It is a result of the 45 correlated design decisions displayed in the boxes of Table 4. The choice of design values in these boxes is up to you until research defines better parameters. Table 4 is simply an algorithmic tool that correlates these decisions to give you the vocabulary and language needed to lead shelter design decisions toward your design objectives.

The total impervious cover required for the home specified on line 23 of Table 4 is presented in cell J43. When this 2,700 sq. foot area is combined with the 9,300 sq. ft. of unpaved open space in cell B68, a 12,000 sq. ft. lot is produced containing the 77.5% of unpaved open space, or 9,300 sq. ft., noted in cell B68. This total complies with the minimum lot area required by the R6 zone. Column D in the Density Module also shows that the home would fit in five other zones when the unpaved open space percentage in column A is adjusted as noted. If you look at column EE in Table 2, however, the impervious cover pertaining to these zones in the current ordinance is substantially greater. So who is right? If the impervious cover capacity of the storm sewer is 30%, line 66 in Table 4 is right and Table 2 represents serious excess.

I should also mention that line 29 in Tables 1-3 was rejected by the community in 1968 as a minimum living standard. It permitted 53% impervious cover and the desire for larger home sizes on these small lots led to variance requests that were often permitted. These variances increased impervious cover, reduced open space, and eventually led to the need for a relief sewer at public expense. These variance approvals were often combined with additional variance requests to reconcile conflicting regulations. The combination of increasing intensity, decreasing open space, and inadequate infrastructure eventually led to rejection of the R7a zone on line 29 of Table 1, but left the lots as a lesson that was not fully understood.

Based on my experience, unpaved open space on a given lot or land area is a by-product and not a conscious zoning requirement adopted to protect a city’s storm sewer capacity and quality of life. The minimum amounts needed to function as a relief from intensity and a contribution to a city’s health, safety and quality of life has often been considered a “taking” of property value; but who is taking what from whom? The lack of knowledge regarding the value of unpaved open space and the arbitrary nature of uncorrelated zoning requirements leaves an entire city at the mercy of uninformed regulations and variance approvals.

Forty-five values have been entered in the boxes of Table 4 and have been correlated by an algorithm and master equation to produce the results in its Density Module. The specification values entered are interactive and one or more may be modified to produce different results in the Density Module, but the underlying point is that correlated zoning requirements are the key to effective city planning and design leadership.

A measurement system has been introduced in columns H-L of the Table 4 Density Module to calibrate the implications of correlated zoning requirements. Line 66 shows that the minimum preferred single family residential standard in the R7 zone produces 15,379 sq. ft. of gross building area per shelter acre, an intensity of 0.106, intrusion of 0.4, and dominance of 0.506 per shelter acre when the minimum unpaved open space percentage is 70 and the total home area in cell K43 is 2,598 sq. ft.

Cell H66 in Table 4 reveals a contradiction with cell GG28 in Table 3. Table 4 shows that the R7 zone on line 66 can produce 15,379 sq. ft. of shelter area per acre based on its design specification. Table 3 shows that the R7 regulations on line 28 of Table 1 can produce 36,421 sq. ft. of total shelter area per acre. The intensity represented is 0.446, intrusion is 0.5, and dominance is 0.946. Keep in mind, however, that Table 3 represents unintended consequences produced by uncorrelated zoning regulations.

The answer to Question 1 is that achieving a net density limit produces random results when the 45 leadership decisions in the boxes of Table 4 remain ignored or uncorrelated. The density options in column F of Table 4 are based on these 45 correlated decisions. In other words, density is a social measurement that is a product of many physical design decisions.

Question 2 remains to be answered with the measurement, correlation, and evaluation of existing projects based on the consistent topics of a shelter capacity and intensity forecast model.

In response to Question 3, zoning regulations can be correlated to avoid leadership contradictions and achieve leadership objectives with shelter capacity and intensity forecast models.


Lines 32-91 in Table 1 were originally written to address multi-family residential shelter options that I’ll generically refer to as townhouses and apartments. “Townhouses” are horizontally connected single-family residential dwelling units that are not stacked. “Apartments” are connected and stacked dwelling units within a gross building area envelope.


Table 5 is similar to Table 4, except for lines 23-27 and lines 38-42. Design value options have been entered in lines 23-27 to reflect the diversity of bedroom options often available in townhouse configurations. (These additional values could also be changed to reflect home size options in a residential subdivision.) Lines 38-42 calculate the implications of lines 23-27. Lines 53-71 correlate these implications with a master equation to produce the results in the Density Module. The density options related to these correlated design decision values are displayed in cells F53-F71 of the Density Module.

Column F in the Density Module of Table 5 illustrates that density is a function of the 67 optional design values entered in the Land and Shelter Modules of Table 5, and a choice among the unpaved open space percentages entered in column A of the Density Module. If 5% open space is considered, a density of 21.33 dwelling units per shelter acre can be achieved as noted in cell F53, but this is based on a limit of 5% unpaved open space. If 50% open space is provided, a density of 11.23 dwelling units per shelter acre is achieved on line 62 based on the design specification in the Shelter Module. The point is to illustrate that correlated open space percentages and design specifications produce the density limits in column F of Table 5. Keep in mind that each open space increment in cells A53-A71 has a companion storm sewer capacity percentage equal to 1-UOSD% in cells B53-B71. An engineering standard does not necessarily represent an open space provision that protects our physical, social, psychological, environmental, and economic quality of life, however. The measurements in columns H-L of the Density Module have been created to measure these implications.


Table 6 is a variation of Tables 4 and 5. It has been adapted to address the unique nature of apartment design decisions. The Land Module calculates the shelter area available in cells F12 and G12 based on the values entered in its boxes. The G1 Module identifies the net shelter area available in cells F20 and G20 after a number of miscellaneous site plan topic values are entered and subtracted. The Apartment Module defines the “mix” of bedroom types, percentage allocations, and habitable areas under study in cells A30-C34. The building efficiency percentage entered in cell F36 is used to convert habitable area to gross building area per dwelling unit type in cells D30-D34. The garage and parking lot spaces planned per dwelling unit type are entered in cells E30-F34. The design averages representing the dwelling unit mix are calculated on line 36. These are correlated with the open space percentage options in column A and the building height options on line 44 of the Density Module to produce the density options in cells C46-M64. (The correlation is executed with a master equation.)

Table 6 illustrates the number of density options that can be produced from one design specification when unpaved open space and floor quantity options become variables. The specification is represented by the values entered in the boxes of the Land, G1, and Apartment Modules of Table 6. The unpaved open space options have been entered in cells A46-A64. Floor quantity options have been entered in cells C44-M44. Density options are located in cells C46-M64. A choice is made by finding the intersection of an unpaved open space percentage and a floor quantity option. The density located represents the correlation of 68 design specification decisions in the Land, G1, and Apartment Modules plus the unpaved open space and floor quantity decisions in the Density Module. Intensity and Dominance measurements corresponding to the density options found in Table 6 are calculated in Table 7.

The point of this apartment exercise is to show that the density of 34.85 permitted in cell G74 of Table 1 is questionable given a complete design specification containing 70 decisions. It cannot even be found in cells C46-M64 of the Density Options Module in Table 6. In addition to this, the intensity and dominance measurements calculated in Table 7 indicate that many of these choices are not desirable; but this conclusion is based on my opinion, and it will only convince others when supported by consistent measurement and evaluation of many existing multi-family residential apartment projects based on a standard specification vocabulary and language.


Compilation, correlation and consistency of planning data evaluation can yield city design knowledge. This is the opportunity implied by Tables 4-7. Table 8 has been created from Table 4 by removing all calculation line items. The data entry boxes remain to form a questionnaire for the G1.R1 Activity Group. The intent is to use this modified forecast model to record existing and proposed shelter project data for evaluation. If the residential activity topics were removed, it would e a questionnaire for the G1 Design Category. (The gross building area options for a design category can be used to shelter any activity.)

A completed questionnaire represents a project data record. Record values can be entered in a related forecast mode. Tables 4-7 have been examples of forecast models that calculate shelter design and impact implications. For instance, columns B-F in Table 4 calculate design implications based on 23 design decisions and 22 floor quantity choices. Many more design implications could be calculated, but these have been presented as examples.

Columns H-L in Table 4 calculate the impact represented by the 23 design decisions and 22 floor quantity options in the table. Impact is measured by calculating the shelter capacity, intensity, intrusion, and dominance represented by the design specification and each floor quantity option in the Design Module. The data in the module implies a question:

        What impact parameters on the 22 lines of the Density Module are undesirable?
Given the incomplete and conflicting nature of current zoning regulations, this remains a land owner driven decision without a correlated city design strategy and land use policy. Project records, evaluation, and city design forecasting can begin to answer the question when all members of the shelter design and construction community begin to use a common, cloud-based method of preliminary planning and evaluation. I have the models if someone wishes to invest in the application.

All calculations have been based on the G1 Building Design Category. It represents buildings served by parking around, but not under, a building. Classifying buildings by parking system permits an infinity of appearance and activity options to be organized into 6 building design categories: G1, G2, S1, S2, S3, and NP. A design category is occupied by one or more activities to form an activity group, but activities are a social consideration. The gross building area available to shelter these activities is the product of a physical design specification containing many correlated decisions. These decisions directly affect the massing, pavement, and open space fabric of the projects, neighborhoods, districts, cities, and regional areas we occupy. Our success in designing this fabric contributes to the quality of life we create.

You have just read about the G1.R1 (single-family), G1.R2 (townhouse), and G1.R3 (apartment) activity groups. The S1.R3 activity group represents an apartment building served by an adjacent parking garage on the same property. The parking capacity of the S1 garage influences the gross building area potential of the site. Gross building area is subdivided by an apartment design specification to determine the apartment capacity of the gross building area. If an S1 design category building became an initial design decision, the Table 6 forecast model would be replaced by another. The floor quantity options in the new model would be changed, and the density options calculated would increase significantly. These optional building categories are not anticipated by the density regulations in Table 1. This omission, and the omission of unpaved open space specifications, means that a developer may seek to achieve these permitted high densities with a surface parking lot. The attempt can produce a sea of asphalt around a tall building with no open space relief in sight and little attention to storm sewer capacity.
I have used a number of terms in the Conclusion without definition. Table 9 places them in context with a Built Domain classification system that includes an explanation of their meaning.

TABLE 9: Classification of The Built Domain




The Built Domain: All physical creations of man on planet Earth
The Natural Domain: All of planet Earth, except The Built Domain
Phylum: one of two elements of The Built Domain
Division: one of four components of a Phylum
Cohort: a primary unit of a division encompassing similar, but not necessarily compatible, activities
Category: A primary unit of a cohort with a unique physical feature such as, but not limited to, a parking system
Group: A unit within a category containing similar activities or functions

Urban, Rural

Shelter Division


Residential, Non-residential

G1: Surface parking around, but not under, building
G2: Surface parking around and under building
S1: Structure parking adjacent to building on same premise
S2: Structure parking underground
S3: Structure parking at grade under building
NP: No parking required

R1: Single-family detached, unstacked residential
R2: Single-family attached, unstacked residential
R3: Single family attached, stacked residential (apartments)
NR: Non-residential occupant activities are too extensive to separately itemize, and may require customized design specification templates.

Location: Address and parcel number(s)
Capacity: Gross building area in sq. ft. per acre
Impact: Intensity, Intrusion, Dominance, Density
Class: Appearance or Style: a designation from architectural history and landscape history can be debated but is helpful.
Code: Use group, construction class, and occupancy limits: This level of detail is difficult to gather. It is optional for this reason, but essential for a complete library of information.

Movement Division


Roads, railways, air traffic, water traffic, subways, bikeways, sidewalks, and so on

Airborne, terrestrial, aquatic, and subterranean

Intercontinental railways, short-haul railways, international airlines, local airlines, intercontinental shipping, local ferries, intercontinental tunnels, local subway systems, and so on

Function: (e.g., local, collector, arterial and freeway road systems)
Service Level: level of demand or design

Open Space Division


Federal, state, regional, local and private

Preservation, participation, defense, and buffer

Campgrounds, day visits, lodges, proving grounds, and so on

Function: active, passive, restricted, or prohibited use
Service Level

Life Support Division


Agriculture, energy, communication, health and safety

Airborne, terrestrial, aquatic, or subterranean

Farms, hydro-electric dams, sewer systems, water systems, power systems, communication systems, medical systems, food systems, and so on

Function: active, passive, restricted, or prohibited use
Service Level

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