A complete guide to everything you need to know when building a log home.
Lag bolts are sometimes used in place of spikes because they are considered easier to install, and some people feel they offer more holding power.
Nails are primarily used in sill and post construction systems to attach the horizontal logs to the vertical posts.
Thru-bolts are generally anchored to the foundation at the corners and every 24 to 36 inches thereafter. The logs are pre-drilled and the thru-bolt inserted. A nut and washer are added at the top of the wall and tightened to pull the wall together.
Drift pins are usually metal rods 1/2-inch in diameter and 2 to 3 feet long. They are inserted in pre-drilled holes at various points to provide lateral stability and added shear strength to the wall.
Adhesives are generally used in combination with mechanical fasteners to provide greater protection against air infiltration.
Tongue and groove systems use tongues and grooves that are milled in opposite surfaces of the logs. When placed together in the wall, they act to prevent infiltration of air and water.
Splines are another sealing system. They are generally composed of either fiberboard or plastic and are inserted into special grooves cut into the top and bottom of logs. (Both spline and tongue-and-groove systems also require the application of chinking, caulking or insulating foam to complete their seal.)
Caulking is often applied internally along the tongue or groove to form an adhesive seal. However, it can also be applied externally along the seam just as effectively. When applied externally, it lends an aesthetic touch to the logs.
Chinking is similar in performance to caulking. Generally applied to the exterior of logs in 2- to 3-inch strips, chinking also gives a distinctive appearance to the home.
Foam tape is applied along the top of the tongue. There are many different types of foam tape, but all are designed to maintain a seal as the logs shrink and swell with weather changes.
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Log Butt Joints
Most machine-milled logs aren't long enough to span the entire length of the wall, so joints are created at various places in the wall where the logs are butted together. Modern log builders use several methods to ensure a weathertight seal at each butt joint. These include the use of splines, dowels and gaskets.
Fiber splines are inserted into kerfs, or vertical cuts, in the ends of logs at the butt joints.
Arrow splines are a variation of the fiber spline. The points on the plastic arrow spline are designed to form a tight seal at this joint.
Dowel splines are another variation wherein the logs are butted together and then drilled to form a round hole. A dowel is then forced into place to form a tight seal.
Foam gaskets are often used in addition to splines to provide an even tighter seal.
The corner design of a log home gives its distinctive look and style. The corner design is also important with respect to engineering since it provides a tight seal and strengthens the wall. Modern log shaping and sawing machinery has made possible many intricate corner designs that add to the ease and quality of the construction.
The choice of corner design is primarily the owner's aesthetic preference. All designs seem to work equally well. There are five basic corner designs:
Butt and pass corners are created when one log butts into the side of the other, which passes to form the classic stockade corner
Saddle-notch corners are created in round logs when the upper log is notched round to fit over the intersecting log. Both logs then continue past the point of the intersection.
Interlocking corners are similar to saddle-notched corners. However, modern machinery has made it possible to shape all four surfaces precisely, thus creating an interlocking design.
Dovetail corners are generally created in square or rectangular logs to provide the distinctive dovetail design.
Corner posts are used when the intersecting logs butt into a corner post.
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Windows and Doors
While the walls are being erected, they must be prepared for the installation of the windows and doors. Log home producers recommend several methods of handling this task.
Window Bucks. As you construct the log walls, a rough frame called a window buck is installed in an opening cut to your window size. The actual windows are installed later. It may be necessary to extend the jambs because of the thickness of the log walls.
Complete Windows. Another method is to supply windows with rough frames attached and the windows mounted in them. These framed and finished windows are then installed in one step. This method eliminates an added step of having to go back later and install the windows. It does, however, increase the likelihood of breaking a window during the construction process.
Special Windows. It is also possible to install large windows and windows with special shapes, such as bay, bow or trapezoid. These windows generally require a bit of extra planning, so make certain you specify for these windows well in advance.
Window Bracing. In systems where the walls are actually built around the window frames or windows, these frames need to be securely held in place during the construction process. This method requires the use of many braces. It is important to make certain the windows and doors are plumb and true as the work progresses.
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Joist Systems for Second Floors
With the walls complete up to the plate level, or the level at which the second floor is installed, it's time to move to higher ground and install the second-floor system.
In 1-1/2- or 2-story homes, the second-floor joist system can be made with heavy timbers, logs (or a combination of the two), or dimensional lumber or floor trusses. Each system has some advantages.
Heavy Timber or Log Joists. Exposed heavy timber or log joists can be very attractive in a log home. They are not too difficult to design and build, but they may add extra cost to the home. One of the more important considerations when using them is the question of concealing ductwork and plumbing and electrical wiring, normally installed behind the first-floor ceiling. All of these problems can be easily overcome if you include the use of timber or log joists in your initial plans.
Joists and Floor Trusses. The use of 2-by-10-inch or 2-by-12-inch dimensional lumber or floor trusses for second-floor joists is also very common. They provide the same advantages when used as second-floor joists as when used for subfloor joists. These advantages include long spans and ample room to hide ductwork, pipes and electrical wiring. Often these advantages are gained when they are used in just part of the home while using large timbers and log joists in other parts. This dual application often provides the means of hiding utilities.
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There are many roof systems available for a log home owner. Both budget and aesthetics play an important role here.
Log and timber trusses can be spectacular in a log home. The use of log purlins serves the same function as rafters and trusses by holding up the roof, but they run perpendicular to ordinary rafters, leading to some interesting effects when the roof decking is installed.
Prefabricated trusses are the most economical to build and install. However, they generally limit the design to a flat, finished ceiling system and may result in a much more restricted use of the attic space because of the webs or supporting members of the truss.
Attic frame trusses are a variation of prefabricated trusses in that they are designed to provide room size space within the webs of the truss. This truss is an excellent choice for 1-1/2-story homes where you want to use the attic for bedroom space.
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Once again, you have several choices when it comes to insulating your roof system.
Batt insulation is the most common method of insulating an attic and is generally selected when installing prefabricated trusses and a flat ceiling.
Built-up roof systems are generally used when you choose log rafters or a heavy timber truss system in your log home. You will be able to see the roof system from inside the home, while allowing the use of roof insulation.
To accomplish both objectives, you again have a couple of choices. The first is a built-up roof system in which you nail decking over the log trusses and then actually build a second roof above that roof. This method creates the space needed to install either batt or solid foam insulation between the inside and outside roof.
Pre-engineered, insulated panels are another option. These panels are generally 4-by-10-foot sandwich panels with attractive paneling on the inside, exterior-grade plywood on the outside and 3 to 6 inches of rigid foam insulation sandwiched between them.
Every log home has a distinctive look, and that look needs to be complemented with appropriate roofing material. Here again, you have several choices, including composition shingles, wood shakes, metal or tile roofing materials.
The choice will say a lot about your style and taste. Many feel that log homes are particularly well-suited for wood shake or shingle roofing. If you prefer the look of metal roofing, you'll have plenty of choices in both the type of metal and its color.
Composition shingles made of fiberglass are the most popular and economical choice. They offer a wide selection of colors and weights.
Tile or slate products are also good choices for your log home. Although they generally have a higher initial cost and can be a little more difficult to install, once installed they can last for decade after decade.
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With the roof securely in place, it's time to install the electrical, plumbing, heating and cooling systems, which are commonly called the mechanical systems.
Installing these systems in a log home is not fundamentally different from installing them in conventionally framed homes, but because the exterior walls in log homes are solid, there are some differences. It's important to remember, however, that most of the interior walls of a log home are stud-framed, open and available for the installation of mechanical systems.
Electrical wiring is installed in exterior solid wood walls simply by drilling the logs and installing the wires as the logs are assembled. Generally, the only wiring in exterior walls is for electrical outlets outside the home, entry wall switches and lights over exterior doors. Electrical wiring for outlets inside the home along solid wood walls can be concealed behind baseboards.
In those cases where the electric service box needs to be installed on an exterior wall, a wiring chase is constructed and covered with paneling to match the logs. Single electrical outlets are easily concealed by recessing them in a solid wood wall.
Plumbing is seldom installed in exterior walls because of the likelihood of freezing. The same holds true in a log home where plumbing is installed in interior stud walls. When plumbing must be installed on an exterior wall, an interior stud wall can be built next to the log wall.
Heating, air-conditioning and ventilation systems are similarly installed in interior walls for the most part. Where this is not possible, a chase is constructed and concealed with paneling to match the wall.
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Throughout this section, we have shown the construction of log homes with solid wood walls. There are a number of log home producers, especially those located in the northern climates, that offer what are called super-insulated log home packages. These homes are actually conventional, stud-framed insulated homes with half-logs applied to the outside and often to the inside as well.
The actual wall consists of interior wallboard, paneling or half-logs, a 2-by-4-inch or 2-by-6-inch stud wall with insulation, exterior sheathing, a vapor barrier and then 2-by-4-inch thick half-log siding. At the corners, the log siding may butt into a corner post to give the home a more conventional look. Some of these sidings feature full-size logs for the corners, which give the appearance of a traditional log home with intersecting corners.
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In the construction sequence we have detailed how to build a manufactured, kit log home. However, many log homes are built by hand, or handcrafted. They are produced and erected in a completely different manner. The following briefly explains the difference.