The city of Mexico will consider changes to the municipal code affecting the definition of accessory buildings in residential neighborhoods, as well as the size of housing, sheds and garages. If approved, the amendments will be applied to future construction.

At last week’s meeting of the Planning and Zoning Commission, Mexico building official Steve Redman outlined the proposed changes. He explained that the additions were necessary because the current code did not adequately define some issues.

Because of this, the city recently issued a permit for the trailer section of an 18-wheel truck to be used — with its wheels off — as a storage building in a residential area.

“There was a significant and very vocal opposition,” Redman explained, adding that the permit was not validated. “City ordinances have to adapt.”

New language would define shipping container storage units and nonconforming structures. In addition, subsections would set minimum square footage of new housing, the size of new accessory structures, as well as allowing for proper modification of nonconforming buildings.

Under the changes, shipping, freight or other large containers -- including the box portions of trucks — could not be used as permanent storage units or sheds in residential neighborhoods. The suggested amendment further limits the number of outbuildings to two.

It does allow for such containers to be used in commercial or industrial zoned districts, pending an additional use permit.

The amended document limits the height and square footage of any garage or other accessory building. New construction or additions cannot be larger than the house.

Redman referred to several distinct structures and explained the new language would preserve the existing character of a neighborhood.

“What this is designed to do is to keep the continuity — or feel, if you will — of a residential district,” he said.

According to Redman, there had been several inquiries over recent years about placing tiny homes on vacant lots. There were concerns, he added, over small houses with a large garage, as well as the impact on property values.

“This becomes problematic,” he said. “We felt it necessary to address that.”

If amended, the code sets an equation to establish the minimum size of a new single family home or duplex. No new home can have less than 600 square feet of living space. From there, the size is determined by the average square footage of neighboring houses.

The changes include a definition and set of rules governing nonconforming buildings. These are structures that predated modern setbacks and other codes.

Redman points out that there are dozens of accessory buildings that sit on property lines. Current ordinances require a five-foot setback.

And under the existing code, he pointed out, “if someone had the land and desire to expand [the building], they would have to demolish the structure” and build to the regulations.

The proposed language allows the existing structure to remain intact. Only the new addition must adhere to code limits.

“We feel like what we have proposed is comprehensive,” Redman said. And because residents retain the right of appeal, “I think there are protections in place.”

The commission approved the suggested changes unanimously. It went before the City Council for consideration on Monday.