Plan Commission Votes to Allow More Three-Story Homes in Evanston

The Plan Commission on Wednesday night, September 12, voted its approval of changes in the zoning ordinance regulating what homeowners can build above the second floor of houses in most R zoning districts. Ostensibly designed to limit a tendency toward de facto third stories, the proposed changes, detailed at pp. 30-36 of the Sept. 12 Plan Commission packet, will, overall, permit more construction at upper heights in residential districts.

Under current zoning, houses theoretically can't be more than 2-1/2 stories, and new construction and additions are limited to 35' tall. That maximum height is measured using the mean between the roof's high and low point, so a roof can actually peak at 40' or higher. The "half story" is so-called because "liveable" square footage (space with a 7-1/2' or taller ceiling) above a second story is limited to 60% of that of the second story. So a house with 1000 s.f. on the second floor can have 600 s.f. of attic "liveable space" above that.
As a practical matter, only half of the space under a typical peaked gable or hip roof is "liveable" height, so owners and developers of peaked-roof houses to achieve 60% or more use dormers, currently limited to half the length of a roof, to push out portions of sloped roofs.
The overall result has been, as City staff put it, new construction or additions that "dwarf" neighboring houses because of actual height and bulk; top stories often don't resemble an attic but feel, to a neighbor, like a full third story next door.
The new ordinance, which has gone through several iterations over the summer, changes maximum height measure to absolute peak, not mean height, of a roof, and would reduce the percentage of dormers allowed along a roof's length. These two changes will modestly curtail some top-story bulk strategies. However, they are more than offset by the new ordinance's three dramatic amendments: (1) elimination of the 60% cap on a half-story space, (2) the allowance of a three-foot-high "knee wall" for gable and hip roofs, and (3) the elimination of limitations on building on substandard lots.
The "knee-wall" permission would allow a roof to start three feet above the top of the second story, meaning that inside the attic, the far corner of the room could be three feet tall rather than zero. This change alone will allow hip- and gable-roof attic spaces to achieve at least 70% "liveable space," nearly 80% if dormers are added to the maximum allowed. Meanwhile, mansard and gambrel roofs, no longer constrained by the 50% cap, can ascend at steeper angles. Thus, for all houses, unless the first two floors already are more than 22' or so above grade, significantly more construction will be allowed of houses that are essentially three stories, although that top story will be primarily covered by roof.
These changes apply only to new construction or to houses built within the last 50 years. Older houses, and those in historic districts, will be governed by the old limitations, at least as to height.
An additional significant change likely to affect the teardown market is the proposed elimination of limits on "substandard lots." Currently, each residential district has minimum lot size standards so that houses do not overfill lots, creating a sense of crowding and depriving neighbors of light and air. For example, in R1 districts, lots are supposed to be 7200 s.f. Lots smaller than that district standard have their permissible height limited by 15% to 25%, depending how small the lot is, so that the bulk of a house stays in proportion to the lot. Under the new ordinance, however, this limitation will be eliminated, letting most owners build as high as any other regardless of lot size.
The principal exception to the new relaxed limits may be for newer flat-roofed houses. Or not. Because the half-story and knee-wall definitions are inconsistent and confusing, it at first seems, as staff explained, that flat-roof houses can't have that, even if their half-story volume is no greater than sloped-roof houses' attics. However, until the language is fixed, a legal argument could be made to the contrary.
Because most "substandard" lots are in subdivided portions of Evanston where the majority of homes are smaller, relaxing this limit, assuming past patterns and normal market forces operate, will result in more development on blocks with smaller cottages and bungalows.
A less-debated change to the ordnance will eliminate mean height as the measurement for accessory buildings (usually garages), raise permissible height to 20' for most, and lower it to 14' for flat and mansard-roof structures.
Plan Commission approval of the ordinance is not the final step. Any text amendment to the zoning ordinance must be passed by the City Council after notice and hearing.


Below are my written comments to the Plan Commission, submitted 9/12/2012 with respect to proposed Evanston Ordinance 72-0-12, "Amending Portions of the Zoning Ordinance Relating to Building Height and Dormer Regulations in the R1, R2, R3, R4, and R4a Zoning Districts." 
From:   Jeff Smith
To:   Plan Commission;  Zoning staff
Date: Sept. 12, 2012
The revised version of the roofs and dormers ordinance makes some improvements but still suffers from confusion and unintended consequences. I would have a hard time advising clients with some roof styles what is allowed. Here are the remaining problems:
Roof type differentiation: Principally, the ordinance is still flawed from attempting to differentiate between roof styles -- apparently hip and gable roofs will be allowed a new 3-foot "knee wall" but gambrel and mansard roofs will not. "Half-story" is now defined only as the portion between a "sloped roof" and the top story – so a gambrel or mansard roof structure apparently may cover a half story but with no windows except for end windows unless dormers are utilized. A flat roof apparently may not count as a half story regardless of size, even if it has significant stepback. So modern houses get penalized.
Third stories now allowed: The ordinance says that it is intended to prevent third stories from sneaking in under the guise of half stories, but it accomplishes the opposite. The illustration in the packet on p. 26 shows this. Imagine a house that, after stoop and 2 stories, has a generous 15' between the top of the second story and the 35' peak of a roof (assume 2' of stoop and 9' per story). Without a knee-wall, only 50% of the floor space of that attic will be 7.5' tall or higher. The 60% limit currently in place is not achievable for a hip or gable roof without dormers.
If a 3' knee-wall is allowed, the amount of floor space that will allow a 7.5' clearance jumps to 70% -- more than existing limits, without a single dormer even being added. If dormers are added, an additional 30% of the "unusable" 30%, or 9%, can now be made into living space. I.e., 79% of the top story is now used. (If you don't trust these figures, plug in a 24' house width and the Pythagorean theorem). Essentially there is now a third story – for all but flat-roofs. Even a tiny third floor penthouse – that would be truly invisible from the street – is not allowed even if less than 50% of the second floor.
The 60% cap for a half story operated on all types of roofs equally because of math. No roofs had an "advantage" if code was enforced. Even a mansard roof – which was invented to cheat on "story" limits – had to be short enough in most spots, or tilted enough, that 40% of the space was "unlivable." Eliminating that limit makes comparing a "half story" with "35 feet" meaningless and will make faux third stories easier.
Substandard lot "dwarfing." A house is dwarfed by a neighboring house because of height and mass, not the size of the neighboring lot. Relaxing height limitations will provide relief only for substandard lot owners who want to supersize. Since most substandard lots border others, this "relaxation" will result in more, not fewer, substandard-lot houses – bungalows and cottages – being dwarfed. It will incentivize speculative purchases and teardowns – and result in more mass on smaller lots.
Since the changes are ostensibly to prevent inconsistency on a block and "dwarfing," this is backwards. Allowing "monster houses" on substandard lots is likely to result in the opposite of the stated goal. The changes IMHO also will incentivize teardowns of the last truly affordable detached single-family homes in Evanston.
More on knee-wall: The ordinance says that a knee wall is not visible from the ground which is just not so. By contrast, it is possible to build a recessed, stepped-back flat-roof half-story (as defined under existing Code) that is invisible from the ground. That's the whole point of stepbacks. Plus, since the ostensible concern is adjoining houses, the ground view doesn't matter so much as the neighbor's view.
Environmental impact: Uninhabited attics are generally insulated and unheated. Incentivizing development of attic into livable space, while it will generate permit fees and higher property values, brings heated and cooled living quarters that much closer into contact with the outside, requiring more heating and cooling. Power consumption will increase. Ditto smaller dormers: the more corners and projections, the greater the heat loss. Green building principles tend to utilize solid walls.
Summary: My main objections are the unequality between house types, the lack of clarity in the "35 feet or 2-1/2 stories whichever is less," the somewhat arbitrary nature of the dormer rules, and that the changes accomplish in several respects the opposite of their stated goal. Vis-à-vis half stories, the ordinance replaces a clear standard (60% of the square footage of the floor below) that applies equally to all buildings with unclear standards applied unequally, but which allow the favored structures to go to nearly 80% -- essentially allowing the sneaky third floors that are the supposed problem!