FACTS:

Petitioner constructed a house and found out that Go was encroaching on her  land.    A  relocation  survey  was  then  conducted  and  it  was  found  out that her total land area was decreased while the land of Yao increased.   
 

HELD:

Where  a  person  had  no  knowledge  that  he  encroached  on  his  neighbor’s lot,  he  is  deemed  a  builder  in  good  faith  until  the  time  the  latter  is informed of his encroachment upon the latter’s property.