The Nantucket Conservation Commission on Thursday continued a redevelopment application for property at 92 Washington Street after commissioners said the filing lacked required detail on alternatives, buffer lines and utilities.

The application, presented by Jack Vaccaro of Epsilon Associates, proposes removal and replacement of an existing house, detached garage with a studio above and a separate shed, all within land subject to coastal storm flowage. Vaccaro said the project would raise the primary house on piles to reach BFE+2 (first-floor elevation slightly above 11 feet), shift the garage, and reconstruct the shed. He said the plan includes permeable crushed-shell driveway surfacing and a retrofit to buried utilities and a new driveway entrance from Washington Street Extension.

Commissioners said the presentation and submitted materials did not include a written alternatives analysis required under the commission’s “no adverse impact / no reasonable alternatives” standard, nor did the plan show the commission’s recently revised performance-standard buffer lines (including the 75-foot buffer associated with Coastal Bank). “You just said that you think there’s nothing else that’s possible, but we are required to get a delineation of all the options,” Chairing Commissioner Linda Williams told Vaccaro.

Williams also noted the commission’s updated performance standards for land subject to coastal storm flowage and asked that the project be referred to the town’s Coastal Resiliency Advisory Committee (CRAC) for advisory review on whether the redevelopment could conflict with conceptual roadway-raising work identified in the Nantucket Coastal Resiliency Plan. Commissioner Tim Brane agreed to bring the project to CRAC for consideration before the commission’s next hearing.

Other technical items commissioners requested include a written calculation of proposed square footage changes for the three structures, a clear plan showing whether mechanicals, utilities or tanks will be located within regulated areas, and a delineated 75-foot buffer line on the plan of record. Vaccaro said he would provide the requested information and that the applicant would work on an alternatives analysis and the other details requested by the commission.

The commission continued the hearing to Oct. 23 at the applicant’s request. No vote on the substance was taken; the continuation preserves the commission’s ability to require additional materials and to condition any future approval based on Natural Heritage time-of-year restrictions and other protections if appropriate.

The developer and the commission also discussed that the site lies within FEMA velocity and Zone AE flood zones, and that piles will provide about six feet of clearance from grade to the bottom of the elevated structure. Vaccaro said the project does not propose new septic disposal on site and that best-management practices for landscape fertilizer use on Nantucket would be followed.

The commissioners’ requests and the continuation mean the commission will review revised plans, a written alternatives analysis, and CRAC feedback at the Oct. 23 meeting before deciding whether to close the hearing or issue an order.

The discussion occurred during the public hearing portion of the Oct. 2 meeting and remains an open item on the commission’s docket.