John E. Weidemuller, founder and president of Weidemuller Construction Co., a Baltimore-based heavy construction company, died Saturday at Union Memorial Hospital of complications from a fall. He was 86 and lived in the city's Guilford section.

Born and raised in Pittsburgh, he earned his bachelor's degree in civil engineering from University of Pittsburgh in 1937.

Mr. Weidemuller began his career with the Army Corps of Engineers and, during World War II, worked for Koppers Co., revamping closed steel mills that were needed for the war effort. Shortly after being transferred to Baltimore at the end of the war, he established his business.

The company specialized in building warehouses, churches and firehouses, but also constructed the western approaches to the Bay Bridge and worked on the Delaware Memorial Bridge. Locally, his company built the Locke Insulator Co. plant in South Baltimore and the Highlandtown fire station on Eastern Avenue.

He retired and closed the business in 1977.

Mr. Weidemuller had been an avid equestrian, and a member of the Boumi Temple mounted patrol. He was active in other Masonic organizations, with memberships in Dallas Lodge and the Scottish Rite. He was a former board member of the German Orphan Home in Catonsville.

He was a member of Second Presbyterian Church, 4200 St. Paul St., where a memorial service will be held in the chapel at 11 a.m. tomorrow.

Surviving are his wife of 65 years, the former Geraldine Wendler; a son, John C. Weidemuller of Cockeysville; a daughter, Carol W. Fitzpatrick of Riderwood; two grandchildren; and a great-granddaughter.