Whoever buys a gut-rehabbed South End house won't be able to use the basement because the builder installed it without getting zoning approval first

The Zoning Board of Appeal this week rejected plans for a new basement at a West Canton Street manse now on sale for $6.9 million because the developer basically dug it out and finished it even though he didn't have approval.

The board and the mayor's office both said they're willing to overlook such things with new property owners and consider a back-dated approval, especially given the chaotic situation this summer with construction and the pandemic, but they said Peter McLoughlin is an experienced Boston developer and should have known better than to build something he didn't have permission for as part of a gut rehab of the 1890 structure.

At a hearing on Tuesday, McLoughlin's attorney, pleaded extenuating circumstances: He said McLoughlin had approval to install a new groundwater-recharge system - to ensure rainwater would be pumped into the ground to protect nearby foundations - but stopped work on that when Mayor Walsh ordered a halt to construction work in March due to Covid-19.

During a July inspection, an ISD inspector said McLoughlin needed to do some emergency work to shore up the building and the developer decided it made sense to simply finish the planned basement work - meant for a home office and gym - as part of that work.

The problem is that a completed basement would make the building denser than allowed under the street's zoning, which would require board approval, which McLoughlin did not have. LaCasse said McLoughlin has since filled in the basement so it can't be used at present.

Faisa Sharif of the Mayor's Office of Neighborhood Services, however, urged the board to reject the request because of the way the basement was built. She said McLoughlin is hardly some homeowner new to Boston who may have inherited a situation that he was unaware of.

"In this case, it's very clear that this was an experienced developer that had gone before ISD to seek something they knew required zoning relief and decided to build already," she said.

The board then voted to reject the required "relief" the basement would need. The board did, however, approve McLoughlin's request to add a hatch to the roof to allow access to the new roof deck he's put on top of the house. The roof deck itself is allowed under the street's zoning, but the hatch needed board approval.