Dream Home Tip - The Nature of Materials
by John Rattenbury, Architect
The materials of which the building is built will go far to determine its appropriate mass, its outline and, especially, proportion.-FLLW
A common misunderstanding of this principle is that it means that the materials that you should use in a building are ones that can be found naturally on the site. When
appropriate materials can be found on the site, so much the better, but that is not what is meant by the nature of materials. The word "nature" in this context refers to the
individual attributes, or special qualities, that characterize each material and give it distinction. Materials are the resources of architecture. Every material has its own
significance, its own potential, and its own limitations. It has its own unique appearance, rough and finished, and one material should not be made to imitate another. We
should respect the essential qualities of each material, find its true nobility, and use it honestly in ways that are appropriate to its nature.
There are many characteristics to consider: strength, durability, plasticity, workability, weight, hardness, resistance to water, texture, color, transparency, and economics. The
best way to get a feel for the nature of a material is to work it with your hands.
Masonry and Tile. Brick, concrete block and stone are solid, durable, and strong when resisting compression. They will sustain heavy vertical loads. Masonry units may be
formed into arches or domes, which transfer loads to the side, but unless reinforcing is added they lack the ability to resist tensile forces. The character of their inherent
massiveness should be expressed in a design.
Brick is the earliest of man-made materials. It comes from a natural earth substance, clay, which is shaped and baked by fire (adobe bricks are sun-baked). The dimensions
of this shape become a small repeated unit mathematically related to the larger unit geometry of the structure. When we use brick, we color the mortar to match the brick,
striking the vertical joints flush and raking out the horizontal joints. This makes the wall appear more monolithic and, at the same time, emphasizes the horizontal line, the
line of repose.
Stone is one of wonderful nature's materials, comes in many types. Some, like marble and granite, can be polished. To know how to lay stone in a wall, study it in its natural
state. In a stone quarry we see the characteristics of each type of stone. Sedimentary rocks like sandstone or limestone are stratified into ledges. When placed in a wall, they
will appear most natural if they are laid in a strata-like manner.
Tiles are made of clay, stone, or manufactured materials and come in all sorts of shapes, colors and textures. Since they are relatively small units in size, they can cover curved
surfaces.
Concrete, capable of being formed into almost any shape we can imagine, changed the face of architecture. Used by the Romans, it had only limited use until steel was added.
When concrete, which has a high compressive strength, is combined with steel, which is high in tensile strength, we have reinforced concrete, a material that resists both types
of forces and has true plasticity. There are many ways to manufacture and improve concrete, such as air-entrainment, dewatering, gunite, prestressing and post tensioning. It
is interesting to note that the first patent for this reinforced concrete was issued to Joseph Monier in 1867, the year that Frank Lloyd Wright was born.
Steel can be shaped in several ways-cast, rolled, flattened into sheets, or drawn into slender wires. Most effective and economical when used in tension, its amazing tensile
strength is demonstrated in a suspension or stayed-cable bridge. Its properties are uniform and its strength a mathematical certainty, so there is no need of waste. It has
tenuity, a characteristic seen in nature in the lightness, strength and continuity of a spider web. Its drawback is that it rusts when exposed to weather (unless it is Corten
steel).
Plaster is a fluid material while it is being applied. Easily adapted to almost any shape, it is susceptible to a variety of textures. When color is mixed into the plaster or stucco,
it looks better than a coat of paint. Although plaster is subject to cracks, synthetic materials with plasticity can be added to help overcome this inherent weakness. Gypsum
board has virtually replaced plaster (except where there are compound curves), and is easier, cheaper and faster to install.
Glass is a remarkable material because to some extent it is invisible. It allows for views, both in and out, introducing a sense of freedom to architecture. The daylight that it
brings is a great blessing but something to control, since along with the beneficence of light and warmth comes unwanted glare and heat. Clear glass also creates a lack of
privacy. Reflections from the exterior surface of glass are a problem because they reflect both heat and glare to other buildings and to people. Office buildings with all-glass
facades are a prime example. Shading the glass is a natural way to mitigate some of these problems. Glass may be tinted or layered, and now we have "intelligent" glass that
keeps heat and ultraviolet rays out but allows daylight to enter. Future development will bring down the cost of a new type of glass that can be "tuned" to different colors,
opacities and reflectance.
Plastic is, of course, a synthetic material, and one that is being used more and more in a variety of ways as a building material. Being fluid in its manufacturing process, it
can be given almost any shape, color, texture, or degree of transparency. Plastic is certainly the material of the future. Science will produce new types of plastic with a wider
range of uses.
Wood. A carpenter knows the essence of wood: its strength, the different shrinkage factors between "with the grain" and "cross grain," and the beauty of different slices and
veneers. The beauty of wood lies in its variety of grains and color tones. They express the fact that it was once alive. Like all living materials, it is subject to decay and must be
maintained. By laminating wood we have created plywood and glu-lam beams. By combining wood chips with plastic we have produced particle board.
These are just some of the materials that we use. There are many others-copper, stainless steel, fiberglas, fabrics, and hundreds more.
Recognizing the individuality and distinction of each material, we seldom allow the surface of one material to be set flush with the surface of another material. If a brick wall
meets a wood wall in the same plane, there will be an offset where the two materials join, even if it is only an inch or two. When we use glass, we often we cut a slot, or rabbet,
in a wall and run clear glass into it. This creates a seamless indoor/outdoor connection.
Our imagination will let us see, in each material, it's own inherent characteristics. All materials can be beautiful. Their beauty depends on how well their individual nature
is appreciated, and the sensitivity with which they are used in a building. Materials used with integrity and sensitivity produce a beneficence that is hard to come by in
other ways-a sense of human warmth. Many people who live or work in an organic building have noted this.
Color is closely related to texture, and color without texture usually has no quality. Whenever we deal with texture, we must consider light. Without light, texture cannot
appeal to our sight, only to our touch. In the sunlight, texture takes on a continual change in appearance as the sun strikes it from different angles. In the many of the
communities which we have master planned, we establish guidelines for colors. These restrict buildings to a palette of appropriate earth tones, and they play a major role
harmonizing a community with its environment. If we truly understand the inner nature of a building material, we will use it in an appropriate and honest way to bring out
its best features.
