Implications of Construction on Design
Once you have an idea where all the rooms go and what size they are, you need to think about the limitations created by how the building will actually be built. Many traditional building methods actually started here, with the main limitation being place by what size beams could span a ceiling or floor. With modern materials this is less of a concern, but by paying attention to the limitations, both materials and money can be saved.
As with every aspect of design, ideally the designer has every tradeoff and limitation in mind while designing, but even then, there is some inevitable round of changes. Architecture is like a tile game, shoving things around till the desired outcome is achieved.
33)
Simplicity
Simple buildings are easier, and hence cheaper, to build than complex ones.
They generally also use less material, primarily because there is less cutoff
waste and less bracing for each corner. The tradeoff is that a box (the simplest
shape) can't always meet the other design needs of the building.
Buildings whose shape is determined largely from aesthetic concerns tend to be more expensive to build and less functional than ones built for functional reasons with aesthetics in mind.
34)
Materials and Sizes
Industrialized production reduces the cost of processed materials, but results
in those materials coming in only fixed sizes. Many books suggest that you
should design at increments of these sizes, e.g. at multiples of 2,4 or 8 feet,
but because doing so creates fairly severe design concerns, few designers have
succeeded in doing this on a grand scale.
A more practical method is to design with those sizes in mind, but don't force things to them. It is more important that the building dimensions be what they need to be than you reduce the number of cutoffs you make in framing. A better solution it to keep the cutoffs in sorted piles, e.g. a piece of 2x4 that is smaller than 14-1/2" is not useful for blocking in 16"o.c. walls, so sort a pile of shorts based on that. Someday when lumber is really expensive, you'll have to do that anyhow.
While there is a wide variety of finish materials out there, at any given time you're limited to what is currently in style, and what appeals to a broad enough market. By seeking out antiques, and other reclaimed items, a sense of "character" is added to the building that can't be achieved any other way. These items tend to be the most loved in the house, but certainly come at a price because of the quantity of labor involved.
35)
Super-insulation/Deep sills/Thick walls
Thick walls definitely cost more to build than thin ones, but the benefits are
also great. Walls have three uses: slow the transfer of heat, act as sound
barriers and divide spaces. Thick walls give a building a sense of solidity and
protection from the elements. They also increase comfort by raising the
mean radiant temperature of the room, and create deep window sills that are
great places to put plants, a coffee mug, the book you're reading etc, as well
as providing a great sound barrier.
Thick walls also take up space, which on small urban lots can be a challenge1. In all but mild climates, exterior walls should be thick due to holding extra insulation: anywhere from 7 to 12" of it. By using foam board, thinner walls can be achieved. Thick walls also are challenging in that wider sills, jambs and liners are required for windows and doors, but enough builders have done thick walls that there are a variety of solutions available. For new construction, thicker foundations, or wider slab edge footings are often used (in spite of the fact that the second wall is supposedly non-bearing).2 For retrofits, the additional wall is usually hung off the existing one, either by adding a foam board skin, or using Larsen trusses.
Non-insulating thick walls: wall areas can be thickened with bookcases and cabinets also, when there is a desire to create a sense of greater separation, but insulation isn't needed. These thickened areas can be used to create alcoves also, for example a sitting area by a window.
Thick walls can also be a sound barrier, by some combination of insulation, sound insulation board (homosote for example), by hanging sheetrock on resilient channels, or with a sheetrock soundboard, which uses a special elastomeric material between two thin sheets.3 Closets, bookcases and cabinets also reduce sound transmission.
36)
Wabi-Sabi
No matter how well crafted a house is, there are always small imperfections.
In the "fine homebuilding" style, craftsmen use great skill to reduce these to a
minimum and hide the rest. In the "natural building" style there is an
emphasis on hand made items, where the idea is to show that something is hand
made by celebrating the small imperfections rather than hiding them.
Rather than smooth wall sheetrock with no visible divots, walls are hand
plastered to a wavy, unmistakable hand made finish. Note that this is very
different from a textured wall finish, which looks like poor quality smooth
wall, not a hand done finish. In some sense it is similar to the "rustic"
look.
This idea can be carried out throughout the house, into the finish trim, doors, windows etc, although clearly it is important that windows and door function smoothly, even if they don't look that way. This "natural" look gives much more flexibility in using reclaimed materials, since those materials often have marks in them that are difficult to remove. If one things of these marks as "patina", or the Japanese concept of wabi-sabi, which is the idea of imperfections being the natural state of things, then reclaimed materials are not only easier to use, but you get an added benefit of bringing character into the house that can only otherwise be acquired via many years of use.
As a corollary to this, always build things to last a long time, because they will hopefully have many uses.
37)
Natural materials/Toxics
There is no inherent reason that manufactured products have to be more toxic
than less processed or "natural" ones, since some natural materials are in fact
somewhat toxic. It is true that most natural materials used in
construction are not toxic. The issue really isn't one of natural versus
manufactured, but what the actual toxicity is. To some degree there is
also a tradeoff in performance and cost versus level of toxicity allowed.
Wood, glues and other natural materials will off-gas to some degree, and some
manufactured materials like interior grade particle board are notorious emitters
of formaldehyde. People with chemical sensitivities have a much greater
concern than others.
The gray areas are the most controversial. Products like OSB, glue-lams, TGIs and other engineered wood use a glue that emits formaldehyde, but cures quite rapidly to a very low emissions level. Most green builders find these products benign, but others find them unacceptable. Since they are so prevalent, they are hard, but not necessarily impossible, to avoid.
For a public skeptical of manufactures claims, there is a serious breach of trust, and this to some degree has driven the natural building movement. By adopting a pragmatic approach to toxicity, there is very little limitation in material selection: wood trim instead of MDF, plywood and wood cabinets instead of MDF, or the occasional use of exterior-grade MDF, or one of the non-toxic MDF products.
In addition to the issue of toxicity, there is a definite "feel" created by materials. The use of "natural" materials tends to remind one of nature, while more industrial materials, such as are commonly used in the "modern" style, have a more hip, urban feel, while low cost materials are often lacking in character. While this is undoubtedly a gross generalization, I think most readers will agree that the choice of materials has a significant effect on the feel of the house, although exactly what is undoubtedly a subject of much debate.
Notes
1: one idea is to allow up to a 4" incursion into the setback provided that the incursion consists of insulation beyond code.
There is still some controversy about how much insulation is necessary for moderate climates, and to a large degree its a tradeoff between up-front construction costs and long-term energy costs.
2: admittedly there is no standard thick wall construction technique, the most common techniques are double walls with one load bearing wall and single 2x6 or 2x8 walls with a foam skin.
3: alas, the material is quite pricey. You can also buy the material itself, which comes in tubes and is applied with a caulking gun. The only product I know of is "green glue".