South Mountain Company, one of the largest architecture and design-build firms on the Vineyard, is looking to expand its mixed-use campus in West Tisbury.

During a public hearing before the Martha’s Vineyard Commission last Thursday night, owner John Abrams described plans for an additional 3,600 square feet of lumber storage, a 600-square-foot solar storage shed, and converting existing lumber storage space into offices at their property. The expansion would increase the number of employees on the property from 18 to 24, the number of parking spaces from 35 to 40, and include the clear-cutting of 12,000 square feet of trees.

The property also includes 16 clustered residential units at Co-Housing, four of which were required to go toward affordable housing when the commercial business was approved in the residential zoning district in the 1990s. Because the commission predicated South Mountain’s original mixed use permit on the creation of those affordable housing units, the expansion now on the table led to a conversation on Thursday about the commission’s role in enforcing affordable housing contributions from its applicants.

“It seems like this is the only stumbling block we seem to have here,” commissioner and public hearing chairman Richard Toole said on Thursday.

Mr. Abrams proposed offering the commission $150,000 that would go to an affordable housing project of its choosing. While the commission’s newly revamped affordable housing policy would require Mr. Abrams to contribute approximately $100,000 or an equivalent amount of affordable housing square footage, he believed that this larger lump sum figure was appropriate, and felt that contributing bedrooms would be more effective than space.

“Our belief is that the offer is a generous offer, and may do more good than the staff proposal,” Mr. Abrams said.

Although commissioners appeared to have no qualms with the amount of money, some felt that Mr. Abrams should consider building the affordable housing units, which would equate to three bedrooms, on South Mountain’s property, rather than the money going to a different project. Even though the commission would have final approval over the affordable housing contribution, some commissioners also expressed concern about ceding too much control over the money to the applicant.

“Sometimes people would like to give money to their pet project without any community review of whether that is the best,” commissioner Linda Sibley said.

Mr. Abrams said that ultimately the West Tisbury zoning board of appeals would also have a say in the affordable housing contribution because the project involves a 40B zoning permit. Larry Schubert, chairman of the West Tisbury affordable housing committee, said the town had just issued a request for proposals for a three-unit duplex in the former firehouse off Old Courthouse Road, suggesting that might be a favorable place for the monetary contribution. Mr. Abrams agreed.

“We’re proposing that we will put that money where it will do the most good,” he said.

Three residents of the Vineyard Property Association, a housing development southwest of South Mountain, raised concerns about the expansion of a commercial enterprise in the residential neighborhood.

“We are immediate neighbors of John,” resident Byron Hartley said. “John, we believe, is a good neighbor. The difficulty we have is . . . he is a businessman, and he is doing what businessmen do. And that in itself is not compatible with the community.”

Mr. Hartley said he felt the expansion would impact an already busy intersection at Stony Hill and State Roads. The commission declined to perform a traffic study on the project, believing that the traffic impacts would be minor.

The public hearing was closed. Deliberations and a vote will take place in the near future.

In other business, the commission held a public hearing on an expansion to the Carroll’s Trucking facility located off Vineyard Haven-Edgartown Road in Vineyard Haven. The proposal is to construct a new 51,000-square-foot self-storage building, reconfigure the traffic flow on the property and install a new denitrification system. Commissioners continued the public hearing to a later date.

The commission also voted not to require a public hearing on a historic house demolition located at 556 Chappaquonsett in Tisbury, sending the project back to the town level. Tisbury building inspector Ken Barwick referred the home to the commission because it was built in 1880, but multiple renovations have been made to the home since, thereby decreasing its historic significance, commissioners found.

Using a metric upon which the commission scores the historic significance of old homes facing demolition, the Chappaquonsett house received a 3 out of 13. The metric factors in age, historical or cultural significance, its design, location, and whether town review is required.