Building continued for the next eight years. In 1805 another row of buildings, 145 feet long by 19 feet high and wide were added and another 38 feet were completed in 1806. In 1806, a gallery was also added to protect walls from rain. New missionary houses built in 1807 and five soldiers' homes, a storehouse and guard house built in 1810 continued the expansion.
By 1811, after eight years of continuous building, the quadrangle, measuring 350 feet each side, was finished. The following year, an earthquake damaged the church and buildings, creating huge cracks and toppling some of the walls. It took six more years to finish the church and adjacent campanario, which was dedicated on July 4, 1817. The church was 140 feet long and 25 feet wide with 30-foot tall buttressed walls five feet thick. The pine timber ceiling, made of wood brought from the mountains 30 miles away, supported a tiled roof.
Building continued into the 1820s, including a new grist mill and reservoirs and an elaborate water system to carry water from the mountains for livestock and crops.
Like most missions, Santa Ines fell into disrepair after secularization, but it was never completely ruined. A tenant who was a bricklayer helped keep it repaired, and Father Alexander Buckler, who arrived in 1904, began a restoration that continued into the late twentieth century. The original bell tower fell during a 1911 rainstorm and was replaced with wood and plaster structure that lasted until 1949, when it was replaced with a concrete campanario holding bells cast for mission in 1807, 1811 and 1818. (NOTE: Some say the bell tower was damaged by an earthquake but the church's website says it happened during a rainstorm.)
The current restored building has the original sugar pine beams from 1817, original floor tiles and designs on altar and ceiling beams painted by Indians. The statue of St. Agnes on altar is believed to have been made at the mission by native artists. The reredos was painted by Indians in 1825 in a fresco style on the adobe walls, using vegetable colors
