Juana Briones was known as a healer who raised a big family, opened her door to many in need and persevered to win a divorce from an abusive husband — something unheard of in the early 1800s. In 1844 she bought the 4,400-acre Rancho La Purisima Concepcion and lived there until not too long before her death in 1889. What Briones advocates have been trying to do for several years now is preserve the part of the house that’s built of a very unusual construction called encajonado, an old rammed-earth technique that exists in only three other houses in California. On the Juana Briones Heritage Foundation Website, the house is described as Palo Alto’s oldest, with a construction date of 1846. In May a judge is expected to issue a decision that will make the difference between a house repaired and a house demolished.