Depends on what you are saying about 'Estrada's'
If you mean there are more than one Estrada, you use Estradas, which is the plural form.
If you mean something belongs to someone named Estrada, you use Estrada's which is the possessive form.
If you mean something that belongs to the Estrada family, that is, something that belongs to more than one Estrada, you say Estradas'
Does that help?