After 1906, Gill’s favored materials were concrete and magnesite, a “wood stone” that could be troweled on to create a seamless, easy-to-clean surface for floors and counters. Magnesite became popular in the 1920s and 1930s, but Gill began to use the material at least ten years earlier.
He invented a thin wall construction method of wood and metal lath that eliminated the hollow spaces in walls which could act as flues for fire. He reduced the thickness of walls, normally more than five inches thick, to about three inches. He often filled his concrete walls with hollow clay tile. He believed, stubbornly, in the efficacy of concrete: it was cheap and created the austere smooth surface he liked.
Gill’s notes about the concrete work for the La Jolla Women's Club and the sequential construction photographs provide unusual detail for one of Gill’s significant civic designs.
Robert H. Aiken is usually credited as the tilt-up pioneer in the U.S; he constructed several building in the Midwest between 1905 and 1910. When Aiken went bankrupt, Gill purchased the jacks and tilt-slab table in 1912 and used them to construct the Sarah Clark house (1913), Mary Banning house (1913-14), the Woman’s Club, and the La Jolla Playground Community House. Gill put great faith in concrete and this system and founded the Concrete Building and Investment Company. Although he kept the equipment at least until 1923, his venture lost heavily. It was in the end an expensive way to build.
Gill built several tilt-slab buildings, but his investment in the Aiken equipment was not successful. The Schindler archive includes Gill’s invoice for renting his equipment for the construction of Schindler’s Kings Road house in 1921, but we don’t know how often Gill was able to rent out his equipment and expertise to other architects and builders. The cost of the additional formwork that was necessary for concrete walls, added to the cost of storing and moving the equipment, made construction more expensive than traditional wood framing.
The Horatio West and Lewis Courts are among the best examples of Gill’s intentions and compositional strategies. Richard Neutra was sufficiently intrigued when he first saw Gill’s buildings in 1925 that he included Horatio West, and several other Gill buildings,in his 1930 book, Amerika.
Gill was constantly searching for better ways to build. He used the patented Kahn bars in his concrete buildings, very soon after they were invented by Julius Kahn, brother of the architect Albert Kahn. These metal, reinforcing plates have flanges that help to resist shear in beams or slabs. Gill re-designed his window frames to make them of fewer parts. He was quick to include new labor saving devices in his more substantial houses, such as garbage disposals, vacuum systems, and other developments.
Gill’s intention was to make his buildings as efficient as possible, and that is certainly true for this hospital, funded by Joseph Sefton and built on the grounds of the Children’s Home. The hospital was built of concrete to make it easy to keep clean and free of infestation. The operating area was well lit by natural light through the use of large skylights in the roof and a wall of windows.