With the much-discussed big-house bylaw now a fact of life in Chilmark, discussion at the town planning board this week turned to preservation of historic houses.

Pamela Goff, who owns a pre-Revolutionary house off Tea Lane, asked the board to consider an amendment to the bylaw approved by voters last year to regulate very large houses. The first-of-its-kind bylaw could have the unintended consequence of actually encouraging people to demolish old houses instead of preserving them, Mrs. Goff said.

“I’ve been going over the pre-Revolutionary and pre-Civil War houses listed in the master plan and it made me realize how many of them are essential to the look of Chilmark,” she said. “These old houses are very important to the town and important historically.”

Mrs. Goff said there are five or six properties with pre-Revolutionary houses “in transition,” either on the market or recently sold, and she was concerned what would become of them.

“In the last 15 years we’ve lost five houses,” she said. “For 250 years they lasted and in five years of extreme wealth they were gone.”

The so-called big-house bylaw requires a special permit process for houses that exceed 3,500 square feet on a three-acre lot. Home size is capped at 6,000 square feet per three-acre lot. Existing homes that exceed the threshold are allowed a one-time exception to increase the living area size by five per cent.

Mrs. Goff wondered whether some sort of exemption should be contemplated on the square footage limits to help preserve historic structures.

“How do we give the owners some little incentive not to tear them down, something that might give them the incentive to keep the houses up?” she asked. “I’m afraid with the stripped-down square footage allowed under the new bylaw that people have the incentive to tear them down and have additional square footage in a new structure.”

Planning board chairman Rich Osnoss agreed.

“It would at least show some intent on our part,” he said. “I certainly value it and I think other people in town do too. There’s so much character there.”

Kate Warner, a West Tisbury architect who attended the meeting, questioned whether a square footage exemption was the best approach since it would create a loophole that could possibly be abused.

“I’m worried if you give an exception on volume,” she said.

There was also discussion about creating a fund to help Chilmarkers maintain and restore historic homes, perhaps using Community Preservation Act funds.

The board agreed to ask the subcommittee currently working on the Squibnocket beach project to expand its responsibilities and explore amending the bylaw — with discussion to be continued.

In other business, a public hearing was held on amending the Squibnocket district of critical planning concern to clear the way for the upcoming public-private project at the town beach. The hearing was continued.