The Atherton Planning Commission on March 26 approved a tree protection zone (TPZ) exception to allow a rear addition that encroaches on the TPZ of a 60-inch coast redwood at 5 Calata Way, and code enforcement warned that any ongoing work must stop until required permits are issued. Staff recommended approval, and the commission voted unanimously in favor. Jerry Martin, assistant planner, told the commission that “staff does recommend that the planning commission approve the tree protection zone exception” to allow an encroachment of 5.5 times the diameter at breast height around the 60-inch coast redwood. The proposed project would expand the rear of the main residence by about 763 square feet; a detached accessory dwelling unit has already been approved by building and planning, Martin said. The tree-protection memo attached to the staff report says the project arborist characterized the redwood as healthy and estimated that construction would impact up to about 5 percent of roots, a level the arborist called a minor impact. Sally, the town arborist (last name not provided), wrote that redwoods tolerate construction impacts well and concurred with the applicant that the rear location is the optimal place for the addition. During public comment, Wayne Lin, the architect on record, said alternatives would “further encroach into the TPZ of that tree and potentially the TPZ of other nearby trees” and that placing the addition elsewhere could “block where the family room enters yard.” Lisa Marie Daley, code enforcement officer for the Town of Atherton, told the commission that there were no issued building permits for the main residence or the ADU from September 2024 and that “there should be no work being done on that property at all until the permits are issued by the building department.” Daley said she would coordinate with the building department and that any unauthorized work could lead to stop-work orders, penalties or double fees. Commissioners raised concerns after an on-site observation that trenches had been dug and interior demolition had started before the TPZ exception was considered; staff said the town arborist had inspected fencing around the tree and that work inside areas not protected by the TPZ may proceed, but not within the TPZ. Planning staff noted that building permits ordinarily are not issued until at least 10 days after a decision to allow for the appeal window. The commission’s motion referenced the draft tree protection zone exception certificate and cited the town’s categorical exemption process under CEQA and local code provisions for minor alterations to land. The motion passed with all commissioners voting in favor. The commission discussed follow-up enforcement: staff and code enforcement will inspect the site, and if work exceeded approved limits the matter could be returned to the Planning Commission for additional action. No member of the public opposed the TPZ exception at the hearing.