Homebuilding Acworth GA
Custom Builder, Neighborhood Developer, Volume Builder
Greater Atlanta Home Builders Association
Custom Builder, Neighborhood Developer, Specialty Contractor
Certified Professional Home Builder, Earthcraft House, EnergyStar, Greater Atlanta Home Builders Association, National Association of Home Builders
Certified Professional Home Builder, National Association of Home Builders
Homebuilding the Offbeat Way
To Malcolm Wells, May 14 is Underground America Day, a holiday he invented in the 1970s. Observance of UA Day isn't widespread among the 3,000 other owners of underground homes, but Wells doesn't really care. 'The point is that this is still a good way to build a home,' said the 75-year-old architect from Brewster, Mass. Wells' devotion to an offbeat home-construction technique is echoed in at least five other alternatives to the standard procedure of using 2x4s (or 2x6s) and balloon framing (or 'stick-built' framing) to erect livable structures. From timber framing to in-filling with clay and wood chips, alternative home-building methods today offer well-tested ways to be warm and cozy in the winter and cool and dry in the summer. And although some approaches require special materials and techniques or may only be appropriate in certain climates or locations, few alternative building methods are beyond the abilities of a quick learner who has a surfeit of common sense and drive. Here's a rundown of these methods, along with their advantages and drawbacks.
Insulated Concrete Forms
This increasingly popular construction method relies on concrete and recycled plastic for its structural integrity and excellent insulation values. It is most popular in areas where lumber prices are high, due to the absence of big local forests - areas such as the desert Southwest, the Great Plains and southern California. But it's readily adaptable to just about any terrain, climate and location. Moreover, it offers an alternative building method with few practical disadvantages. Each manufacturer of concrete-filled foam blocks has its own method of making the basic building material. But to one extent or another, they all make their blocks out of a high percentage of recycled polystyrene, which is an excellent insulator against heat, cold, sound and critters. The blocks are reminiscent of old-fashioned cinder blocks because they are hollowed out in the center. But because the basic building material is so light, the blocks can be, and often are, much bigger than cinder blocks, sometimes several feet in length and width. They are either glued together or manufactured so that they interlock. Once together, the blocks create a honeycomb of tunnel-like air spaces inside a wall cavity. The spaces usually run both vertically and horizontally. Steel reinforcing bars are then located in the vertical floor-to-ceiling cavity. Then a special mixture of concrete is pumped into wall cavities, where a vibrating tool drives out all the excess air, making certain the cavities are filled to capacity. When the concrete hardens, the wall is essentially complete, with concrete and iron on the inside and polystyrene on the outside, offering an insulating R-value of about 32. The R-value of the standard 2x6-stud wall filled with fiberglass batting is 19. The nearly waterproof polystyrene surface is easily cut with a special knife, saw or router for the plumbing and wiring raceways. Obviously, window and door openings would be created before pouring the concrete. The rough openings usually include a wooden nailing surface for the finished doors and windows themselves. Interior walls are either plaster or standard drywall panels glued in place and finished as desired. Exterior walls are either stucco or siding glued in place. The biggest shortcoming in this construction method is cost. Even in areas of the country where plasterers and stucco masons are plentiful, a foam-block home will cost around 15 percent more to build than a comparable balloon-framed house. Where plasterers and stucco masons are scarce, the cost goes up even more. And if you opt for a siding like clapboards, cedar shingles and the like, the cost goes up even more because of the laborious preparations needed to give the rough exterior a reliable nailing surface. Of course, foam block advocates argue that energy savings over the years will compensate for the higher initial costs. But that's little comfort when you're writing those big monthly checks to cover the mortgage. Also, in rainy climates, the permeability of the foam blocks could allow water penetration or water buildup in the walls over time. Design considerations and more costly exterior siding options generally prevent the water problem from developing but again drive up costs.
Straw-bale construction burst on the home building scene in the 1990s, although variations on this type of construction have been around for nearly 100 years. Similar in theory to foam-block construction, straw-bale construction offers a less expensive building medium with a very high resultant R-value in the walls - up to R-50 depending on the size and quality of bales used. The method is also far cheaper than foam-block or balloon-framed construction, usually coming in about 10 to 20 percent under stick-built houses. To build with straw bales, a foundation must be poured with vertical, reinforcing steel bars extending eight to 10 feet above grade. The straw bales are then spiked down on these rebars in a staggered, brick-like manner. Where wide gaps are necessary, wooden planking is used to reinforce the bales above. After a truss-style roof is applied, the 18- to 24-inch-thick bales are plastered on the inside and stuccoed on the outside. Straw-bale construction has been most popular in areas where the climate is relatively dry. That's because it's imperative to keep the bales absolutely dry from the moment they come out of the field until the final coats of plaster and stucco are applied. Otherwise, mold, mildew and rot can set in. It's also essential to use only straw, not hay. Straw is left over when wheat, oats or other grain-bearing stalks are stripped of their seeds. Any seeds left in a bale have the potential to germinate and expand from the inside, cracking wall coatings on the outside. Hay is simply dried grass, which is chock full of seeds that are generally not removed, since unlike other grains, they are not used for food. In addition to the dampness and seed issues, many straw-bale homeowners report problems with rodents. When done properly, mice will not be able to penetrate stucco or plaster. But as the years go by, a crack here or a chip there may invite a furry critter inside the walls. Once in, their tunneling and home-building abilities are truly remarkable, though not desirable.
Thermal mass is a term you hear a lot when considering a prefabricated log home. It has been a touchy point when log home advocates debate proponents of other types of home construction. To understand it, a working knowledge of how log homes are built is essential. Log homes today are far more than rough logs stacked one on another, as was the case in Abraham Lincoln's day. Still, log home walls are essentially solid wood. The same timber that faces the outdoors also has a side that faces indoors. But that's where the similarities end. The 'logs' of today are more akin to carefully cut timbers, fitted together for maximum airtight integrity. Indeed, the only thing that looks like a debarked log is the exterior-facing, finished surface. The ends of these 'logs' are notched in the traditional manner, interlocking at the corners of the structure. But along the mating surfaces, most logs in kits fit together like stacked tongue-and-groove lumber, usually with a weatherproof sealant at the mating surfaces for good measure. When finished, the only insulation between you and the elements is that wall of logs. Some have argued that an 8-inch wall of wood does not have as high an R-value as a standard 8-inch wall filled with insulation. That's true. But log home advocates quickly point out that the thermal mass of the logs prevents heat loss in the manner in which heat is rapidly lost through an ordinary wall. Many experts agree and have concluded that heating or cooling a log home is about on par with most other modern building methods. Beyond that, log homes lend themselves strongly to an open approach to interior design. Although newly cut softwood logs are a creamy whitish or light brown color when first installed, they do darken considerably over time, becoming various shades of medium to dark brown, depending on the species of wood used. With a fairly open interior and a generous amount of natural lighting, the gloominess these colors impart is easily dispelled. For the environmentally conscious log-home builder, the National Association of Home Builders says log homes are no threat to the nation's forests. The association says that 37 percent more timber is grown than harvested each year and that all new-home construction accounts for barely 50 percent of that harvested timber anyway. (The rest goes to pulp and paper manufacture.) Moreover, log homes account for only 3 to 5 percent of all new homes built, the association says. So it appears a log home has little impact on ecological concerns in the nation's forests.
The big sticking point with the post-and-beam revival in the 1970s and 80s was the demand for extra materials and high labor costs. In essence, those early timber-framed homes were built twice: once for the labor-intensive, post-and-beam skeleton and then again using variations on standard stud framing for the surrounding shell of energy-efficient walls, roof, windows and doors. Now, both the labor and materials problems have been largely solved. Precutting all timbers at a central mill has reduced labor. This controlled environment offers much-improved results over earlier on-site efforts. When milled offsite, the timbers can be monitored for structural viability and moisture content, both crucial factors in the long-term stability and appearance of the house. They can also be cut more precisely, so the integrity of the joints is never left up to how somebody feels on a given workday. Both materials and labor have been saved with the advent of special structural panels for the exterior walls and roof of a timber-framed home. These ingenious panels are like a big ice cream sandwich with the exterior wall on one side, the interior wall on the other and, in between, a hefty layer of solid foam insulation. The R-value for such a panel (often called a stressed-skin panel) is well above the R-20 generally recommended for walls. The panels are locked together by using one of several clever building devices and, if done correctly, an airtight structure is assured. Little tunnels for plumbing and electrical necessities are cut in the foam before the panels go together. It's all a remarkable step forward from 'the good old days' of timber framing. The interior surfaces of these wall panels are basically the same as surfaces in homes built by more conventional means. Thus, in interior finish work, you can design anything from the rustic, open approach to a more refined 'paint-and-paper' interior. Of course, kit construction does put some limitations on the design of your timber-framed home, which will cost 10 to 20 percent more than a comparable stick-built home. Some manufacturers will precut a custom-designed home, but that drives up the costs again.
Clay combined with organic fillers has been a basic building method for thousands of years. From the American Southwest to the northern German forests, the binding ingredient of clay along with insulating elements like straw or wood chips has been used to keep homes warm, or cool, and contribute to the structural integrity of the building. When formed into small, stackable, clay-straw bricks, the method is called adobe. When used in a wall formed by laths, the method is wattle-and-daub. And there are dozens of variations on each of these themes, from rammed-earth methods to giant pottery-like approaches. The use of compound organic homebuilding techniques is rooted in a desire to reduce dependence on manufactured wood products and thereby help preserve forests. In some areas, the appropriate clay and fillers are significantly less expensive than manufactured wood products, adding a financial incentive. And since building with these materials releases you from the carpenter's dictates of everything being plumb, flush and level, more unskilled labor can be used, including beginner, do-it-yourself adherents. Some methods allow for molded artistic touches that are impossible to achieve by just about any other building method. As with straw-bale construction, simply building a wall using these methods is only the beginning of the project. If indoor plumbing, electricity, windows and doors are desired, appropriate allowances (pipe holes, raceways, wooden frames, etc.) must be made as construction progresses. Also, gauging the exact R-value of these methods is inexact at best, since standardization isn't required. It's important to keep the walls of these buildings dry. A stuccoed exterior and plastered interior again contribute to reducing the dampness. Also, extended roof overhangs keep rainwater under control. Roofs in general must be built of materials other than compound organics, ranging from traditional thatched roofs to trusses decked and covered with modern materials. All building is best done in the warm, dry season, making areas with cool, rainy climates poor candidates for most compound-organic approaches.
Mac Wells, of course, was not the originator of underground living. Our cave-dwelling ancestors probably developed the basics of the method when they ran out of available caves but still thought of south-facing hillsides as attractive places to live. Today, underground building is far from burrowing deep beneath the lawn. Most underground homes are either concrete (usually), pressure-treated wood (sometimes) or naturally rot-resistant wood (seldom) structures, built in an area excavated from a hillside (usually) or flat land (sometimes). The one-story structure is usually roofed over with a flat, heavily reinforced, waterproofed deck and oriented with windows and doors facing south or in an arch facing southeast, south and southwest. All walls and roof decks are insulated from the exterior with thick, waterproof foam sheets. The excavated material is carefully pushed and tamped back into place up against the walls. On the roof, the material is replaced gingerly and often without tamping, creating an R-value of 50 or more, depending on the soil type and depth. It would be difficult to build a quieter home. Utilities are installed pretty much like an ordinary balloon-framed or concrete structure. The costs of underground construction generally run about 10 to 20 percent higher than standard balloon-framed homes, particularly when using a contractor who has never built underground before. In areas where soil is thin, imported fill can also drive the costs up. Environmentally, underground homes tend to blend in with their surroundings after a few years, although trees must be kept from growing in the way of the southerly exposure and roots from some species of trees overhead can pose problems decades down the road. Once overgrown with native vegetation, the entire structure blends in nicely with its surroundings.
These methods of home construction only begin to hint at all the alternatives out there. If more exotic methods and materials are considered, homes can be built using everything from lightweight, aerated concrete blocks to recycled tires and cordwood. Aluminum cans, reinforced fiberglass, recycled steel and even sawdust have been used as basic building materials. The only ingredient common to all is the devotee who, for one reason or another, sees each method full of obvious advantages and few disadvantages. But before you decide to create the American dream using methods and materials from someone else's vision of how life should be, consider all potential drawbacks. For instance, most real estate agents agree that selling offbeat homes is a significant challenge. Homebuyers generally shy away from methods and materials they don't understand. So resale of your alternative home may not be as quick, easy or lucrative as you, or your heirs, would like it to be. Additionally, home insurers may look askance at methods and materials with which they've had no experience. Although foam block, timber frames and log homes have gained acceptance, straw-bale and underground homes may be harder to insure at reasonable rates. Likewise, local building codes and inspectors may delay onsite approvals and permit issuance simply because the methods and materials are so new and require extra time to understand. And finding contractors willing to try your methods, which may appear woefully untried to them, is always difficult and usually expensive. So before you try an alternative home-construction method or material, it's best to talk with several people who have used the method and lived in the resulting structure for more than five or six years. It's only after 10 years or more that any home's shortcomings - be it alternative or standard construction - become obvious. Although home construction and ownership always involve compromises of one sort or another, it is best to understand in advance what concessions you will have to make. In the final analysis, it's similar to Ben Franklin's assessment of marriage: Keep your eyes wide open beforehand, half shut afterward.