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blazerwolf
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| 10/31/2000 1:36 PM |
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Basic homebuilding hasn’t changed much over the last hundred years. But the amenities of living have changed dramatically during that time. Indoor plumbing took the lead in the early years, then came electricity, then Heating, Ventilation and Air Conditioning and now today? What will the next advancement be in the home building industry? We feel that advancement is here now! The new “buzz words” the consumer wants hear today is “Energy Efficiency and Quality”.
Taking into account the various climates and building styles around the country, designing the perfect house to meet everyone’s needs creates quite a challenge to homebuilders everywhere. Stricter building codes and requirements by city governments add ever-increasing burdens to builders on behalf of the customer and generate higher costs to the construction budget.
BUT! Why aren’t today’s homebuilders really doing anything to improve the energy efficiency of new homes? Old habits are hard to break! Most homes around where we build are wooden frame homes, still built using 1800’s technology, on either a concrete slab or pier and beam foundation with some sort of siding or brick veneer. Traditional 2”X 4” or 2”X 6” wooden framing usually encases fiberglass insulation batts behind gypsum sheet rock. The most important reasons to insulate of course is to keep the home comfortable and to reduce the use of fuel and operating costs. Insulation keeps a home warmer in cold weather, cooler in hot weather, and reduces the over all cost of home operation.
This insulation and how it is installed in most homes is the key to energy efficiency. Insulation’s effectiveness is calculated based on its R-value, which is a measurement of the insulation’s resistance to heat flow. There are several ways that insulation works to stop the movement of heat. Reducing conduction of air and reflection of heat are just two of these ways. This measurement of the energy efficiency of home insulation is measured by a system adopted by the insulation industry from the glazing folks who make windows. To determine how well this insulation rating system works you need to understand how the system works. We need high R-Values and low U-Values (R-Value = measure of the resistance of a building component to the passage of heat U-Value = the coefficient of heat transfer) to derive a measurement. Thus an R-Rating! These R-ratings, as the system is designed to determine, measures the flow of air in a wall cavity and the amount of insulation material required to slow that movement and keep the interior conditioned space at a relative temperature of 75 degrees. Typical 2” X 4” walls are insulated to a R-rating of 13. But to achieve this rating the insulation installer has to have a good understanding of how to properly install the insulation. The R-value of this insulation does not correspond to the R-valve of the entire wall because the other building materials have an effect on the overall wall efficiency. Climate of course will play an important role in how well you need to insulate.
The major cause of energy loss in most homes is through windows, cracks and openings, and most of all, through the roof. So why are so many new homes not very energy efficient? The lack of qualified tradesmen and the use of sub standard quality building products are the primary reasons most new homes are not efficient. So how do we change this? First, the consumer has to demand a better product and second the homebuilder has to want to build this better product. This is going to require new homebuilders to take a second look at what they produce.
The funny thing is we already have the technology available to reduce the loss of energy in most homes, but most builders really don’t concern themselves with trying to reduce these energy losses. They are more concerned with squeezing out the most profit they can get with the least amount of cash outlay for the building materials needed to construct the home. Now don’t get me wrong, I’m all for getting as much profit as I can get but, somewhere there comes a time where profit and quality of the product have to be accounted for to the consumer.
So you say we have the technology! Yes, many new innovations are on the market today that provides the quality and standards that the public will demand in the future. ICF’s (Insulated Concrete Forms) and SIP technology is just a couple of the new systems now available to homebuilders. Structural Insulated Panel, SIP construction, in our opinion, will replace traditional stick framing and pink insulation batts as the accepted norm for new home construction. Unlike ICF’s, which are labor intensive and expensive, the Structural Insulated Panel (SIP) offers speed and ease of construction with strength and durability at a reasonable cost. These are the attributes which will thrust it into the forefront of the building industry. In 1999, for the first time, the number of SIP component homes built in this country surpassed all homes built with so-called alternative building systems, according to Jim Tracy, SIPA Executive Director. Tracy estimates SIP use is currently growing at a 26 percent annual rate.
Just what is a Structural Insulated Panel? In the early 50’s, Alden B. Dow, the brother of the founder of the Dow Chemical Company, started using the newly invented and innovative product called Styrofoam sandwiched between two sheets of plywood to build residential projects. Today’s SIPs share the same premise, with Oriented Strand Board (OSB being the most commonly used exterior “skin”. Foam cores can be made from expanded polystyrene, extruded polystyrene, polyurethane or Styrofoam. Wall panels are made usually in 4 ½” and 6 ½” “thickness’, with roof panels ranging from 6 ½” up to 12” and greater. (Structural Insulated Panels are composed of engineered wood products and stable plastic foams that do not pose threats to the environment.) These load-bearing panels have superior raking strength, bending stiffness and resistance to lateral loads caused by earthquakes or high winds.
A 4 ½” SIP wall, having 3 ½” of insulation, has an actual insulation value ranging from R-14 to R-25, depending on the type of foam used. This rigid foam core does not allow air to move through it. Tests at the Oakridge National Laboratory, according to SIPA Executive Director Jim Tracy, show that a 4” SIP wall with an extruded polystyrene core outperformed a 6” wall with conventional insulation. The result is a more comfortable, quieter and cleaner indoor environment.
SIPs also reduce job site man-hours and waste. Traditional framing methods can waste up to 20% of the wood products used on the job site. This waste winds up in our landfills and runs up the cost of the new home.
Since the panels are made with the insulation already built in, the insulation process is eliminated along with the chance that the installer doesn’t know what he is doing. Additionally, air penetration locations such as electrical outlets, gaps between window and door casings with outer walls, and the myriad of other locations where air may either enter or escape are sealed with on the site spray foam to prevent this energy loss. This complete “sealing of the envelope” so to speak, also prevents dirt, moisture and little critters from entering the home. Fire hazard is reduced dramatically since the foam core prevents the flow of air required to fuel the fire. Electrical chases are pre-routed within the panel, which also lowers the chance of electrical fires and makes for easier installation of the wiring.
The practice of locating air conditioning venting and equipment in unconditioned attic space is like putting the whole system in a big oven and expecting it to produce cold air. With the use of SIPs, everything under the roof becomes conditioned space, making the cooling equipment work easier and more efficient, thus making it cheaper to operate and allowing the equipment to last long |
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