Grandfather 1825? and this is 2013?
for church recordswww.genealogy.nationalarchives.ie
but would be his father
I guess as they are dated 1823-1837 Now used as a census substitute.www.askaboutireland.ie
for Griffith Valuation of 1854 of
Dublin County or Dublin City.www.census.nationalarchives.ie
If its 1925 rather than 1825 go to www.familysearch.org
and find the civil registrations. They start 1864 and end about 1950.
At least his name is Zachary as it should make things much easier.