Rafael Guastavino, an architect and builder of Spanish origin, came to Asheville, North Carolina to work on the Biltmore House in the mid-1890’s. Liking the area, he bought land and built a house near Black Mountain. In 1905, he joined forces with the local Catholic community and fellow architect, R. S. Smith, to design and build St. Lawrence Catholic Church. He has been credited with the revival of an ancient tile and mortar building system that had been used in Catalonia and other parts of Spain for centuries. In St. Lawrence, every horizontal surface in the building is made of this combination of tile and mortar. The Guastavino system represents a unique architectural treatment that has given America some of its most monumental spaces, including Grant’s Tomb, the Great Hall at Ellis Island, Grand Central Station, Carnegie Hall and the chapel at West Point. The crypt of Signor Guastavino is located at the rear of the "Marian Chapel," to the left of the altar.

The style chosen for the architecture is Spanish Renaissance. The massive stone foundations and the solid brick superstructure give silent testimony to the architect’s desire to build an edifice that would endure for generations. There are no beams of wood or steel in the entire structure; all walls, floors, ceilings and pillars are of tile and masonry material. The roof is of tile with a copper covering.

From the foot of the main aisle, inside the church proper, one can realize the beauty of the ellipse and the wonder of the dome. It is built wholly of tiles and is entirely self-supporting. It has a clear span of 58 x 82 feet and is reputed to be the largest unsupported dome in North America.

In a time when contemporary church architecture stresses plush interiors with wall-to-wall carpet, upholstered pews, and many other sound-absorbing materials, it is a rare occasion to experience the "cathedral-like" acoustics of Historic Saint Lawrence. The church has a natural reverberation time of almost four seconds. No other church in Western North Carolina can boast a time that comes close to this "natural echo." Natural reverberation greatly enhances music - both organ and choral - enabling the sound to "mix," and thereby greatly improving ensemble sound. The historic Basilica of Saint Lawrence is truly a National Treasure.