SAUGUS – The Conservation Commission voted unanimously Wednesday to issue a certificate of compliance to the Rubin & Thompson Assisted Living Center at 50 Houston Ave.The facility expansion project as originally presented to town regulatory boards in 2007 would have encompassed 1,380 square feet. The modified plan approved by the commission will disturb 1,699 square feet with the building footprint.The structure overlooking the Saugus River was constructed prior to 1996 and as a result can expand up to 5,000 square feet, providing it falls within local zoning parameters. Rubin & Thompson established the present facility in 2004 to provide an alternative to nursing homes and focus on the needs of those with Alzheimer’s Disease and other dementia-related illnesses.Senior citizens who choose assisted living often do so for its non-institutionalized, home-like atmosphere. At Rubin & Thompson, housekeeping and transportation needs are provided, along with three meals per day served in a common area. Nursing is also available if needed.Richard Salvo, the project engineer from Engineering Alliance Inc., said the center will provide 16 beds with sufficient parking. The owners have negotiated a contract with the state to occupy five additional parking spaces at the Bridgewell housing facility directly across the street.Bridgewell runs the housing units at 53 Houston St. under state jurisdiction.Salvo said Rubin & Thompson are not tenants-at-will.The assisted living center is good for the community, said Salvo, adding, “Elderly folks are allowed to stay in their hometown.”The Board of Selectmen already issued a special permit to allow off-street parking to service the assisted-living facility.Salvo said all other work included in the original order of conditions, including flow-through foundations, plantings along the bank, and temporary erosion-control measures, remain unchanged.The Conservation Commission also issued a certificate of compliance Wednesday to the Hammersmith Village III development.The public hearing for the commercial development proposed at 60 Salem Turnpike, the former Atlantic Lobster Co.,was postponed until March 23.