Dad's grandfather:
Theodore A. Grundmann
in 1930 census: 60 years old. 21 when he married.

THEODORUM GRUNDMANN
 JOANNAM PARKER  Family 
  Marriage:  1891   Saint Paul-Catholic, Jersey City, Hudson, New Jersey 
  Batch No.:M595331
  Dates: 1871 - 1970
 Source Call No.: 1403238 
  Type: Film
 Printout Call No.:None  

William Grundmann (Dad's father) was 16 at 1910 census, when he lived at
368 10th Ave. 

William Robert Grundmann born 23 Jul 1893 Birth certificate # 31655  
Father: Theodore Grundmann
Mother: Hannah Parker
Batch No.: C001345

On June 5, 1917 he lived in Lakeville, Connecticut (from his draft card)

Brother Theodore Anthony Jr. 
Service Info.: SN 1 US NAVY WORLD WAR I  
Birth Date: 21 Dec 1896 
Death Date: 3 May 1976 
Cemetery: Long Island National Cemetery  
Cemetery Address: 2040 Wellwood Avenue Farmingdale, NY 11735-1211  
Buried At: Section S Site 1018  

http://ftp.rootsweb.com/pub/usgenweb/ny/suffolk/cemeteries/babylon/longisland/g/g-27.txt

Theodore GRUNDMANN   
    Birth Date: 21 Dec 1896  
    Death Date: May 1976  
    Social Security Number:  125-01-7474  
    State or Territory Where Number Was Issued:  New York 
  
  Death Residence Localities 
    ZIP Code: 11757  
    Localities:  American Venice, Suffolk, New York 
  Fara Park, Suffolk, New York 
  Heer Park, Suffolk, New York 
  Lindenhurst, Suffolk, New York 
  N Lindenhurst, Suffolk, New York 
  North Lindenhurst, Suffolk, New York 
  Venetian Shores, Suffolk, New York 
  
Helen GRUNDMANN (wife of Theodore Jr.)
    Birth Date: 15 Mar 1901  
    Death Date: Oct 1990  
    Social Security Number:  123-16-8072  
    State or Territory Where Number Was Issued:  New York