PORTLAND — From Bayside to North Deering, housing plans could transform city landscapes.

On Tuesday, May 8, the Planning Board will hold its first workshop on a plan from Maine Workforce Housing LLC to construct a seven-story, mixed-use development at 178 Kennebec St.

The board has not yet scheduled a review of another mixed-use development planned for 280-300 Allen Ave., where Estelle Estates LLC would like to build a complex with an office building and 12 housing units spread through five buildings.

Construction at 178 Kennebec St. comes on a quarter acre of land sold by the city last fall to Ross Furman for $250,000. Maine Workforce Housing principals are Nathan Szanton (75 percent) and Cape Elizabeth resident Robert Monks Jr. (25 percent).

The developers intend to build a seven-story, 46,000-square-foot building with 5,500 square feet on the first floor set aside as retail or studio space. A total of 46 one-bedroom apartments will fill the remainder of the building, with 28 priced as affordable. All housing will be marketed to people at least 55 years old.

The preliminary estimate for construction is $6.6 million, with work expected to start in a year and be completed by June 2020, according to plans. Maine Workforce Housing built Walker Terrace on the city’s West End in 2006, and has redeveloped old mills in Biddeford and the former Huse School in Bath.

The property sold to Furman was one of six sold by the city in the past year as it shifts its Public Works Department to Canco Road, and the second where new housing is planned. On March 27, the Planning Board approved construction of 23 condominiums on a parking lot at 60 Parris St.

Estelle Estates, led by Peter Bouchard, is seeking to tear down an existing home and develop vacant land on Allen Avenue between Washington and Pennell avenues.

The 2,400-square-foot office building would front Allen Avenue, along with two triplexes for housing, according to the project narrative. Three duplexes would extend behind the office building, with one entrance to the entire complex on Allen Avenue.

All housing would be three stories.

Plans indicate the construction would affect more than 9,000 square feet of wetlands, and developers have also filed a Natural Resource Protection permit application with the Maine Department of Environmental Protection for the project.

The largest wetland area impacted is at the sites of the two duplexes behind the planned office building, with some wetlands affected by constructing a parking area behind the triplex units on Allen Avenue.

The project also requires a home at 292 Allen Ave. to be torn down. Since it was built in 1900, according to city tax records, developers are also consulting with the Maine Historic Preservation Commission for any information on the “historical, architectural or archaeological significance” of the house.

David Harry can be reached at 781-3661 ext. 110 or dharry@theforecaster.net. Follow him on Twitter: @DavidHarry8.

A preliminary sketch for development at 178 Kennebec St. in Portland’s Bayside shows how the seven-story mixed-use project would fill the corner of Kennebec and Parris streets.