Evanston aldermen tonight are scheduled to vote on a package of zoning revisions that would reduce current limits on overall building height in most residential zones.

But the changes would eliminate existing tougher limits on the height of homes on small lots and relax some other restrictions.

Height cap

Under the latest version of the rules, recommended last month by the Plan Commission, the absolute limit on building height in most residential zones would be 35 feet.

The 35 foot number is used in the existing code — but it’s used as the average or mean height of a building — so a building with a sloped roof might have a peak as high as 44 feet, depending on the width of the building and the slope of the roof.

Some residents, mainly in northwest Evanston, have complained about new houses or home additions that they claim dwarf nearby homes.

Bulk limit

The existing zoning code also says that that a building can be no more than two-and-a-half stories tall.

And it defines a half story as an area with a ceiling height of a least 7.5 feet and says that to count as just a half-story, that area must be no more than 60 percent of the floor area of the story below it.

The proposed change would drop the 60 percent limit and define a half story as the space below a sloped roof.

The new ordinance would also try to adjust for the difference in the area enclosed under different roof types by allowing gable and hip roofs to have a three foot knee wall above the second story, while gambrel and mansard style roofs would not be permitted the knee wall.

Assuming otherwise identical structures 25-feet wide, built on grade and with 10-foot floor-to-floor heights, under the proposed new rules a home with a mansard-style roof could have somewhat more bulk than one with a gable roof and a knee wall (shown in blue), though the mansard’s slope on all four sides would reduce the advantage somewhat.

The new ordinance would deal with flat-roofed structures through a variation process, after the Plan Commission concluded it would be too hard to draft uniform regulations for those.

Substandard lots

The proposed ordinance would eliminate current height limits on homes built on existing substandard lots, which now often limit homes on small lots to just one-and-a-half or two stories.


The proposed ordinance would revise the city’s restriction on dormers to specify that they apply only to dormers above the second story. But it would tighten the limits on dormer size from 50 to 30 percent of a side wall. Confusion about the application of the dormer rules led to objections to the first version of the new rules.

Nonconforming structures

The proposed ordinance would also make it easier to rebuild older homes that don’t conform to current regulations by automatically granting approval to rebuild a structure that is legally nonconforming because of its height if it is damaged or destroyed by natural events.

Top: A house expansion project nearing completion on Hastings Avenue in northwest Evanston, with smaller homes next to it.

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Evanston wants to shrink home expansion options

Bill Smith is the editor and publisher of Evanston Now.

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