Horace Walker House

Florida, United States

Exterior only

Visible from the street; the inside is private.

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Heritage registerNational Register of Historic Places↗

The Horace Walker House, also known as Castillo Sebastian, stands in St. Augustine, Florida as a compact but ornate example of Moorish Revival architecture, built around 1888 at 33 Old Mission Avenue near the north city gate. Designed by Franklin W. Smith, the two-story residence was constructed using mold-formed concrete blocks—an innovative material that Smith pioneered by incorporating crushed coquina and Portland cement rather than sand, with iron rods for structural reinforcement. The modest two-bedroom, two-bath house exhibits the hallmarks of its style: a flat roof with decorative parapets and a front porch featuring five Tuscan arches, three facing the street. The interior displays considerable ornamentation, with heart of pine flooring and carved wood details throughout the doors and ceilings, anchored by a distinctive double staircase with central landing. Added to the National Register of Historic Places in 1998, it represents Smith's significant contributions to St. Augustine's architectural heritage alongside his other notable commissions, including Villa Zorayda and the Casa Monica Hotel.