Developer unwraps plans for 40-story residential and hotel tower near North Station

A Newton real-estate investment firm today filed plans for a 40-story tower with 400 residential units, 320 hotel rooms and a two-level garage underground garage with 150 parking spaces between Causeway, North Washington and Medford streets - a block that forms the top angle of the Bulfinch Triangle.

To make way for its North Station Gateway project, the RMR Group will raze two smaller office buildings and an apartment building. RMR says it decided to go big after it couldn't find anybody who wanted to rent space in the office buildings.

The proposal also calls for 30,000 square feet of retail, restaurant and "amenity" space on the complex's lower floors, according to the RMR Group's filing today with the Boston Planning Department.

According to the filing, the building will have no affordable units. RMR says instead, it is instead "exploring options to satisfy the Inclusionary Development Policy (IDP) by creating the required number of affordable units in an off-site location near the Project Site." That would require building or contributing to the construction of a number of units equal to 18% of those in the main building, or 72 units.

Exactly at what levels the affordable units will be priced depends on whether the building's own units will be rented as affordable or sold as condos - the filing does not state. If apartments, the off-site apartments could not be rented to people making more than 70% of the Boston area median income. If sold as condos, half could not be sold to people making more than 80% of that level, the other half to people making no more than 100% of it.

Because the building would sit in a coastal area that could flood in the anticipated more severe storms of the future:

Critical infrastructure is elevated above the future flood levels. The ground floor, including lobby spaces for the hotel and residential programs, is designed to meet requirements for future flood levels.

Also, the building will have no gas main for the residences and hotel rooms:

The proposed mechanical system supports the City of Boston’s electrification goals by eliminating fossil fuels from the building. The Project is proposing an all-electric MEP system pathway. An air source hear pump system will serve as the basis for the design of the buildings mechanical systems. Domestic hot water generation will also use heat pump technology with an electric resistance backup system.

The developer says it would rebuild the sidewalks along Causeway and North Washington streets to make them more pedestrian friendly and to add street trees.

251 Causeway St. filings and meeting/comment schedule.