Building along the coast is greatly different than building anywhere else. Exposure to the elements and coastal conditions is a key factor to think about in building a new house. The durability of a coastal home relies on the types of materials used to construct it. Materials and construction methods should be resistant to flood and wind damage, driving rain, corrosion, moisture, and decay. Many new technologies are used in residential construction today, including those resistant to the harsh conditions of a coastal environment.
Often the most enjoyable part of building a new home is selecting the finishing materials and items you will look at and use every day: kitchen cabinets and countertops, appliances, fixtures, flooring, and paint. These are the touches that allow you to show off your own taste and sense of style.
But there are also the materials in your home that you don't see. Selecting the right structural framing products might not be nearly as exciting, but these decisions are among the most crucial for the long-term value, comfort, and structural integrity of your home. The right framing materials help ensure solid floors, straight walls, and crisp rooflines.
The science of the Crumlish Residence is how the home is framed, and what material options exist for framing. Math is used to calculate everything from building loads to girders and beams to stress and dynamics. Lastly, the Crumlish Residence incorporates many new technologies, both in building materials and finishing materials.
Science
A home’s framing (See Figure 1) functions much like the body's skeletal system in that it supports the weight and defines the shape and structure of the home. This framing "skeleton," like the body's skeletal system, needs to be strong and true. Today there are many material options available for the framing of a home.
Among the structural framing members in homes are wall studs, rafters, floor joists, and sheathing. In today’s homes, these and other members are constructed with conventional lumber, engineered wood, or both.
Conventional lumber is the material many consumers are most familiar with– 2x4s and other lumber sawn directly from logs. Engineered wood products include I-joists, and specialty beams, studs, and other framing members made of wood strands laminated together to provide exceptional strength and superior performance. People looking for the highest levels of framing quality often request the use of engineered wood throughout the home. Others who seek to balance value and performance request engineered wood products in applications where necessary and conventional lumber in other areas.The quality of materials and installation of wall framing is critical for determining how straight and even the walls will appear and how well the attached cabinets and fixtures will function. Improper framing can lead to wavy walls; cracks in plaster, paint and tile; nails that stick up; and cabinets that don’t hang evenly. To ensure a flat, stable surface for walls, many builders use engineered lumber because it is consistently strong and straight.
The right decisions for flooring systems can minimize annoying squeaks, bounces, uneven floors, and other structural problems down the road. A floor that feels solid and secure requires joists, rim board, and panels that are consistent and engineered to work together. In addition to material selection, level of floor performance– how solid you want the floor to feel– must be considered. Joist type, joist depth, floor panels, spacing, and manner of installation can all effect how much vibration or movement you feel when you walk across the floor. See Figure 2
Lastly, a big trend in residential construction is complicated rooflines, with multiple ridges and valleys– a look that adds character to new homes. In addition, many people prefer large living and dining rooms, tall and wide foyers, and vaulted ceilings– all of which have required builders to adapt with new roof framing materials and practices. For example, in the Crumlish Residence the kitchen, living room, and dining room are all open to one another with no support columns. Homebuyers should consider the types of beams, rafters, and roof sheathing that will meet their expectations and needs. As with walls and floors, both conventional lumber and engineered lumber choices are available. Builders often recommend engineered lumber for medium and long-span roof sections, and conventional lumber for other applications such as trusses and rafters.
While many people are not used to thinking about framing options, some good decisions up front can save homeowners years of hassle and thousands of dollars in the future. The important thing is to sit down with a builder or structural engineer and talk about expectations for the home and what’s important with wall, floor, and roof appearance and performance.
Math
A well-designed building should be aesthetically pleasing but it must be structurally sound. A functional working knowledge of engineering mechanics and mathematics is a necessity in architectural design and drafting. The engineering mechanics of a home can be divided into statics and dynamics. Statics deals with objects at rest, while dynamics deals with objects in motion or potential motion. The principles of statics and dynamics are combined with information on the strength of construction materials in the design of structures that will withstand the forces of nature and human use.
An effective structural design is neither under-designed nor over-designed. An under-designed structure will sag and collapse, while and over-designed structure will waste material and increase cost. Designers must determine the most appropriate materials, sizes, spacing, and construction methods. Determining building loads is the first step in this process.
The weight of all movable items make up the live load, and the weight of all the materials used in the construction make up the dead load. The live load and dead load together make up the building load. Loads are measured in pounds per square foot (lbs/ft2 or PSF). See Figure 3.
Figure 3: Typical loads for a two-level frame
construction building.
All the weight of the floor system, including live loads and dead loads, is transmitted to joists, girders, or beams (for the application of the Crumlish Residence). To determine the exact spacing, size, and type of girder to support the structure, you must first determine the total load acting on the entire floor systems in pounds per square foot. Divide the total live and dead loads by the number of square feet of floor space. Determine the number of square feet supported by the girder (girder load area). The girder load area is determined by multiplying the length of a girder, from post to post, by the girder load width. The girder load width is the distance extending on both sides of the center line of the girder, halfway to the nearest support. The remaining distance from a girder load area to the outside wall is supported by the outside wall. To find the load supported by the girder load area, multiply the girder load area by the load per square foot. To compute the minimum cross-section area of a girder or beam, divide the load (in pounds) by the material’s coefficient of elasticity: CS = I/E.
The tributary area of a structural member is the area of weight transmitted to a vertical support. The total load of the building is transmitted into the ground from footings and piers through a series of tributary areas. The tributary area over each pier extends one-half the distance to the next structural support members. Use the following equation to calculate the tributary area that is supported by a girder or beam:
W = (f x b d2) / (9 x L)
where W = weight evenly distributed, lb
f = allowable fiber stress, lb/in2
b =width of beam, in
d =depth of beam, in
L =span, ft
For example, if a 6 x 12 beam (actual size 5 1/2” x 11 1/4” spans 18’-0” and the beam has a fiber stress rated at 1,800 lb/ft2, the safe evenly distributed weight is calculated as follows:
W = (1,800 x 5.5 x 11.52) / (9 x 18) = 7,734 lb
Technology
The Crumlish Residence incorporates many new technologies, both in building materials and finishing materials. Building materials include metal roofing, PVC decking, and TJIs. Finishing materials include glass tiles, stainless steel appliances, and vessel above-counter sinks. These new technologies are becoming more and more popular in new construction homes, and each adds some type of importance to the house.
Properly installed, a metal roof should last as long as the house, completely sealing out water, surviving high winds and easily shedding snow. Metal is resistant to fire, mildew, insects and rot. Compared to tile at 750 pounds per square (an area equal to 100 square feet) or concrete tile at 900 pounds per square, metal roofing is lightweight. Most are from 50 to 150 pounds per square. Because metal roofs are noncombustible, they're given a Class A fire rating (the most resistant). Lastly, metal reflects radiant heat from the sun, minimizing midday heat gain. Though the material itself is low in insulation R-value, many systems utilize a dead-air space between the metal and roof deck to increase energy efficiency. PVC decking also has many benefits. It is weatherproof, waterproof, heat resistant, fire resistant, and low maintenance.
Trus Joist developed the wooden I-joist 35 years ago. They are engineered to provide strength and consistency. The dimensional stability of TJI joists helps them resist the warping, twisting, and shrinking that can lead to squeaky floors. TJI joists are lightweight and come in long lengths. This helps save on labor, because they're faster and easier to install than traditional framing. These same features have made them a popular choice for roof joists as well. They consist of a top and bottom chord/flange made from LVL with a webbing in-between made from OSB (oriented strand board). The webbing can be removed up to certain sizes/shapes according to the manufacturers (and engineers) specifications, but for small holes, wood I-joists come with "knockouts", which are perforated, pre-cut areas where holes can be made easily typically without engineering approval. When large holes are needed, they can typically be made in the webbing only (the top & bottom chords cannot be cut) and only in the center third of the span. Sizes & shapes of the hole, and typically the placing of a hole itself, must be approved by an engineer prior to the cutting of the hole and in many areas, a sheet showing the calculations made by the engineer must be provided to the building inspection authorities before the hole will be approved. Some I-joists are made with W-style webbing like a truss to eliminate cutting and allow ductwork to pass through.
Since the 1990’s a variety of modern glass tile technologies, including methods to take used glass and recreate it as ‘green’ tiles, has resulted in a revival of interest in glass tile as a floor and wall cladding. It is now commonly used in kitchens, spas and bathrooms. And while small tiles are still popular, small and large format glass products are now commonly formed using cast and fused glass methods. The smoothness of these last two methods has resulted in a wide variety of looks and applications, including floor tiles.
When it comes to kitchen appliances, stainless steel is probably one of the most popular finishes. With its rich luster and polish, stainless conveys a look of utmost sophistication and adds elegance to kitchen decor. Stainless is versatile enough to mix and match with black, white or bisque appliances. It also complements a variety of wood cabinetry styles, allowing design flexibility to create a distinctive look. Beneath each contemporary, ultra stylish exterior is a host of high-performance features. Highly resistant to rust, discoloration and corrosion, stainless maintains its professional appearance for years. And stainless surfaces glisten with the simple wipe of a towel.
Vessel sinks are also a relatively new technology. Also known as above counter sinks, vessel sinks create a focal point in a bathroom atop a vanity. Available in glass, metal, wood, or china, they can be traditional or contemporary in design.
Conclusion
Science, math, and technology are greatly important to the Crumlish residence. Without the three, the house would not physically be able to exist. The final consruction incorporates the science of physics, from the foundation construction to the roof framing. Math is used in every aspect of framing, from calculating the necessary sizes of girders and beams to calculating the maximum loads on floor joist spans. And last but not least, technology is everywhere from building materials to finishing materials. Even many new technologies are used in the Crumlish residence. Building along the coast is greatly different than building anywhere else. Exposure to the elements and coastal conditions is a key factor to think about in building a new house. The durability of a coastal home relies on the types of materials used to construct it. Materials and construction methods should be resistant to flood and wind damage, driving rain, corrosion, moisture, and decay. Many new technologies are used in residential construction today, including those resistant to the harsh conditions of a coastal environment.
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