The Zoning Board of Appeal today approved changing the main formal use of the Roslindale Square Substation from a restaurant to a beer garden, which will let Turtle Swamp Brewing of Jamaica Plain keep operating there on a more permanent basis.

Turtle Swamp owner John Lincecum says he already has some plans for the space - and the square itself - as big as the new window he hopes to have installed this summer to replace what are now giant sheets of wood covering up the Washington Street side of the old Boston Elevated Railway trolley power plant.

Turtle Swamp had operated a winter beer garden - which kept getting extended well past the end of winter - under a series of temporary permits from the city; the city had originally designated the building for restaurant use. The new designation means Lincecum no longer has to worry about endlessly seeking temporary permits and has more flexibility in terms of opening the beer garden beyond its current Thursday-Sunday schedule for both public events and things such as weddings and birthday parties.

After a zoning hearing this morning, at which his request for a use change was supported by both the mayor's office and the office of City Councilor Tim McCarthy, Lincecum said he is planning a Sept. 14 "coming out" party for the beer garden, as well as plans for using the first floor of the substation beyond just serving up beer, by turning it into more of a community-oriented center, as envisioned by Roslindale Village Main Street and Historic Boston, which spearheaded the renovation of the historic structure.

Lincecum said the huge space would be ideal as a performance hall for bands that need more room than the intimate spaces now offered at such Roslindale Square locations as Birch Street Bistro and the Square Root, and that he's already working with acoustic engineers to figure out the best sorts of sound-dampening curtains and other materials to dampen some of the reverb in a brick space with high ceilings. He said he's reached out to Roslindale Porch Fest, which is on Sept. 14, about using the space as a performance area.

Lincecum can't operate a kitchen inside the building - the Boston Fire Department said he'd need an extensive, and expensive, fire suppression system installed first - but he said he hopes to expand food offerings inside the beer garden by working with restaurants in Roslindale Square to offer an easy way for beer drinkers to order take-out - possibly through an iPad-based ordering system.

He added he's also working closely with the owners of Distraction Brewing, who are nearing their own opening of a brewery on Belgrade Avenue on the other side of Roslindale Square. He said the two beer businesses are more collaborative than competitive - as one example, on days when Lincecum closes the beer garden for a private event, he would send thirsty would-be customers over to Distraction.