Monday, July 27, 2009

1930s Base Molding: Part 2

In the previous DETAILS, I discussed the form of a 1930s molding and its extinction from the pool of available profiles. Here, I will discuss the molding's function because it illustrates a beautiful solution to a pragmatic challenge. Every building must deal with two critical issues, 1) how to sit on the ground, and 2) how to keep water out. A building's exterior cladding solves the second issue but also addresses the first issue. During the late 19th/early 20th centuries, concrete replaced stone as the foundation material for buildings in the U.S. The house under consideration sits on a concrete base. As mentioned yesterday, one of the favorite cladding surfaces for the Tudor Revival was stucco/plaster. Stucco is a great material because it requires no maintenance, unlike wood cladding (typical for New England) that needs to be repainted every 10 years. Thanks to its preparatory semi-liquid state, stucco also takes on some decorative patterns, typically swirls created on the spot by the plasterer. The stucco is physically attached to the structure through a metal mesh, which is then nailed to the wall's wooden studs. Stucco is slightly porous but ultimately prohibits moisture from penetrating into its thickness (usually 3/4").

When a wooden structure sits directly on a concrete base, a system has to be devised to keep the water from seeping into the horizontal juncture. With wooden cladding, the lowest board overlaps the concrete base. With plaster cladding, however, the plaster cannot be attached onto the concrete. Our 1930s base molding solves the problem. Note in the drawing above that the concrete base was poured with a slight notch, a kind of shelf into which a smaller wooden element is fitted. Above the shelf, sits the large structural base beam. The metal mesh, onto which the stucco is attached, extends 1 1/2" beyond and covers the wood sitting in the concrete shelf. Our nice molding is then nailed into the wood. Looking at the drawing, we understand why our molding is so wide. It serves as a base and a bottom seal for the stucco. Its exaggerated curve, moreover, takes the water away from the juncture and guides it gracefully over the concrete.

Our dramatic fascia molding solves a very specific problem. It is painted the same color as the plaster and gives the illusion of a seamless plastic extension of the wall. At the same time, it provides the facade with two simple lines that define a horizontal base datum. Seen on its own, it's a beautiful shape distilling some stylistic principles of the 1930s. It can stand alone to represent the decade's aesthetics, but it also speaks of a complicated resolution between ground (earth), industry (concrete), structure (wood), beauty (plaster) and sky (rain). That's not bad for a miniature piece of great intelligence.

1 comment:

Diana Wright said...

I love this kind of discussion. I hope you will do a lot of it.

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Kostis Kourelis

Philadelphia, PA, United States