What is Shelter Intensity?

 Merriam-Webster defines intensity as: “the magnitude of a quantity (such as force or energy) per unit (as of area, charge, mass, or time)”.

When this definition is applied to shelter, “magnitude” means the quantities of gross building area (GBA), parking, and miscellaneous pavement present, planned, or predicted in square feet on a given property. The unpaved open space that remains is an offsetting influence. The building footprint, parking, and miscellaneous pavement area is referred to as the project’s “impervious area”. When considering
shelter, the “unit” in Webster’s definition of intensity is the buildable land area in acres (BLAC) devoted to the project, including all remaining unpaved open space, except for future expansion area (EXP).

Shelter capacity (SFAC) is a preliminary indication of magnitude equal to gross building area in square feet (GBA) per buildable acre (BLAC) occupied (SFAC = GBA/BLAC). When shelter capacity is multiplied by the percentage of impervious cover (IMP%) present or planned, the result is the intensity present (INT) on the buildable land area (BLA) of a project. Ten thousand is divided into the product of (SFAC*IMP%) to produce a manageable intensity measurement (INT) throughut the spectrum of options that is expressed by the equation:

                                   INT = SFAC * IMP% / 10,000 

Since shelter capacity (SFAC) is equal to (GBA/BLAC), the shelter intensity equation is significantly influenced by the square feet of building mass present on a given buildable land area. It is easy enough to measure gross building area (GBA) on existing property and to measure the shelter capacity (SFAC) of a given buildable land area (BLAC). When the impervious cover percentage (IMP%) is also measured, the intensity present can be calculated.

It is another matter to predict the capacity of land to accommodate gross building area. There are six building design category choices available and each involves a separate design specification template. It is now possible to calculate these predictions, but it remains impossible to ensure that the shelter capacity and intensity levels predicted will not produce excessive intensity. There has simply been no measurable and predictive format for research, knowledge accumulation, and leadership direction regarding shelter capacity, intensity, activity, and economic potential for every present and future parcel in a city’s anatomy.

Most cities will continue to struggle with planning and economic development until they have a clear understanding of the productivity of land and activity in their jurisdiction at the parcel, block, or zone level. At this point, they will be able to respond with informed urban design plans that can produce physical context and economic stability reflecting improved measurement, prediction, evaluation, and leadership direction.

Shelter capacity forecast models can predict the full range of gross building area options available for a given land area, but many are excessively intense and undesirable. This consideration will be at the heart of urban design evaluation and knowledge accumulation. Improvement will depend on the ability to make informed choices based on the implications predicted; the ability to correlate shelter capacity with the economic potential of occupant activity options; and the ability to assemble these choices into a complete, corelated plan that can be adjusted with continuing information sharing, data management, mapping evaluation, and urban design prediction.

For instance, I have mentioned in more than one essay that the average revenue per buildable acre of taxable activity is a function of its shelter capacity, intensity, and activity. The average revenue from all such acres should be equal to or greater than a city’s total expense per taxable acre. If it isn’t, budget reductions enter the picture.

I doubt that any city can assess the relationship of shelter capacity and intensity to financial stability at the parcel level of its anatomy with any degree of accuracy. It does not have the information sharing agreements, data management systems, and mapping format needed to understand, let alone evaluate and plan for the future of available land that will contribute to the revenue per buildable acre it needs over time.

At the heart of all this is a city’s mathematical understanding of its current physical plan and its ability to improve the economic productivity of this land. Understanding the adjacency relationships addressed by zoning is not enough. A city’s productivity improvement will depend on the relationships of shelter capacity, intensity, activity, and location on every parcel within its boundaries. The challenge is to understand these mathematical relationships so that they can be managed to achieve financial stability without excessive intensity on the land it governs.

In other words, the allocation of municipal land for capacity, intensity, and activity determines the total average revenue received by local government from the context created. A city’s ability to balance this equation at the parcel level of planning and urban design will determine its success in learning to live within financially stable, sustainable, and beneficial geographic limits.

If “parcel level” threatens your concept of privacy, then substitute the words, block, tract, or zone. These are the cellular levels of urban anatomy that must be mathematically understood before they can be organized to perform and produce a financially stable and sustainable anatomy that offers a desirable quality of life.

The scope is too great to cover in an essay. I’m including a revised Table of Contents for my book, “The Equations of Urban Design”, to outline the leadership language suggested for shelter capacity evaluation and direction toward financial stability and a desirable quality of life. The first eight chapters classify the building design categories involved. The master equations derived and associated with each chapter predict the gross building area potential of a given buildable land area based on the values entered in its design specification template, and the floor quantity chosen for evaluation.

The objective of a chapter is explained by the “Given” and “To Find” statement listed. The chapter must be read to understand the relationship of forecast models, design specification templates, and value entry options to the implications predicted.

Chapter 9-17 address the building design categories in Chapters 2-6 when they are occupied by various forms of residential activity. The combination of a building design category and activity topic is referred to as an activity group. In this case the building design categories and residential activities in Chapters 9-17 are collectively referred to as the Residential Activity Group. The objective of a master equation in these chapters remains listed in the “Given” and “To Find” statements associated with each chapter.

The point in these chapters is that a gross building area prediction for a given buildable land area and design specification is constant, but its occupant capacity is affected by the unique requirements of the activity involved.

Generic gross building area options, predictions, and implications represent strategic urban design decisions with economic implications influenced by their occupant activity. They require urban arrangement like pieces on a chessboard. These are the choices that establish the foundation of decisions on which cities are built.

Mathematical urban design recommendations that address shelter capacity, intensity, and activity decisions throughout a city can add desirable context among buildings to the scope of their potential contributions to its financial welfare and quality of life. It is a mathematical opportunity and potential leadership language at the present time. If you believe that we must learn to live within sustainable geographic limits that protect our source of life, you may agree that shelter capacity and intensity evaluation, or Tegimenics, is a topic that should be pursued.

Walter M. Hosack, December 2025

Site Plan Relationships and Housing Leadership Decisions

Diagram 1 focuses on the role of open space and movement in and around a single-family residential site plan. The diagram eliminates open space normally devoted to setback areas in a typical single-family residential site plan. It also adds a dedicated pedestrian right-of-way separated from vehicular movement. The intent is to reduce the land required for a home of any size and improve its pedestrian setting; but future expansion would be limited to floor quantity increases, assuming adequate initial structural design.

The atrium concept of Diagram 1 is as old as Rome. It is a departure from Rome because pedestrian access is separated from the plan’s vehicular access to create a social side and service side for the dwelling. The size of the dwelling unit is a variable issue.

The strategy depends on the concentrated use of core open space, the elimination of border setback areas, and the separation of conflicting pedestrian and vehicular movement. The arrangement returns to an ancient atrium pattern but attempts to recognize the vast changes in movement conflict and spatial expectations that have taken place. The plan, however, is not the message nor is it the size of the dwelling unit. The message is the relationship of spaces involved, and the potential reduction of lot area per dwelling unit represented. When a “small home” is involved, the reduction could be significant but it is not an infill suggestion.

If you have been associated with design, you know that there are many answers to the same question, which in this case is affordable lot and housing area.

The diagram is not presented as an architectural solution. Lot area quantities and relationships are the message. These quantities include open space, building height, footprint area, parking area, miscellaneous pavement area, and the role of pedestrian and vehicular movement. They all consume irreplaceable land and they all contribute to the cost of housing. Careful consideration and correlation are needed now that construction cost and land consumption are becoming more visible issues-- as well as correlation with existing housing patterns and adjacency expectations. Based on this:

1)      What are the site plan quantities and relationships that combine to produce a desirable single-family residential quality of life on the least land?

2)      What is a desirable pedestrian relationship with the movement systems that serve the dwelling unit?

HISTORY

Lot size has puzzled me ever since I lived on a 30 x 102-foot lot with a 10-foot front yard setback, a detached garage with driveway to the street that barely scraped by the house, and an alley to the rear that was not wide enough to accommodate a turning radius into a garage. It was one of the larger lots on the street. Other lots were narrower and could not provide driveways, nor could the narrow alley serve their outbuildings with adequate turning radii. I assume horses had no problem in the past. The increase in cars forced houses to use curb-parking on both sides of a two-way street. It made the street a one-way movement system that depended on courtesy and deference to function. The result was frustration, anxiety, and a risk to children. We were warned at home and at school that darting between parked cars could result in injury or death. They expected us to take this seriously.

When we moved to a 50 x 120-foot lot with a 25-foot front yard setback I subconsciously felt relieved but did not realize it may have been from lower density. I later learned that a more affluent suburb had banned 50-foot-wide lots. I have always assumed that this occurred because the lot width did not accommodate attached garages, and that detached garages constrained the rear yard area.

Mandatory lot widths increased to 60, 75, 90 feet and above in this affluent suburb in response to the zone involved. Attached garages with driveways to the street became the norm and curb parking was only needed for overflow visitor demand. Setback areas increased, even though increased yard areas were rarely used and contributed more to the appearance of affluence than to functional need. The standard front yard depth was 40 feet. Side yards also increased but lot depth remained at 120 feet. Curb appeal increased and rear yards benefited from the removal of detached garages, but suffered from the increased front yard depth.

In my opinion, the historic front yard setback concept introduced visual consistency to unify disparate building styles and plans. The side yard setback attempted to reduce the depressing compression of 1 to 3-foot side yard “slots” often found among 19^th and early 20^th century buildings. The rear yard setback attempted to offer a limited degree of single-family relief from the prior intensity of multi-family apartments and tenements. The concept of a “lot” attempted to offer land ownership to more than a privileged few.

YARDS

The location of setback areas on lots is worth considering, since our current front, side, and rear yard concepts add considerable cost to a housing objective that is now being asked to be affordable, but “affordable” is relative, setbacks improve the consistency of piecemeal appearance, and infill solutions have their own potential problems.

SITE PLANS

Every site plan is a cell in a shelter organism. It is served by arteries of movement, open space, and life support that combine to form a Built Domain that is attempting to consume its source of life, the Natural Domain. (I have previously admitted that open space arteries are more of a dream than reality.) The size of each residential cell and its internal quantity relationships, including the home “footprint”, determines the land area consumed and its relationship to its neighbors.

AFFORDABLE HOUSING

Affordable housing will simply be another residential cell in the Built Domain. Its characteristics as an infill solution should be carefully considered to ensure that it does not become malignant. It may be that new neighborhoods and/or zones are required. If new land is taken for the purpose, the risk of continuing sprawl for low density, “affordable”, housing will remain. There are no easy answers in my opinion. This may be why many countries use far more multi-family housing and why the pedestrian orientation of their ancient streets is admired.

URBAN DESIGN

The problem deserves urban design attention on a much larger scale, but this represents a dramatic departure from the piecemeal answers provided by our present approach to single-family residential housing and the sprawl it has produced.

The piecemeal approach was a greater problem in the past. It produced adjacency conflicts that led to public health, safety, and welfare concerns. Master plans and zoning districts were established in response to this piecemeal freedom. The concept is needed in my opinion, but its strict definition of “adjacency” is undergoing refinement, and its ability to mathematically evaluate economic stability at the cellular or census block level of neighborhoods and districts is relatively nonexistent. This is why I have used the term “malignant”. It will remain a matter of opinion until urban design can improve its mathematical definitions.

Walter M. Hosack, December 2025