This invention relates generally to log home construction and in particular, to panelized log home construction.
Log cabins have been used as shelter for hundreds of years. The earliest methods of constructing these shelters utilized round logs notched near the corners to provide structural integrity to the completed building as the logs were stacked. Still used today, this method of construction is extremely labor intensive, difficult to fabricate, often drafty, and requires a high level of maintenance.
Stacking round logs results in a relatively small surface area of log to log contact. In order to produce a continuous wall with a reasonable level of thermal and structural integrity, an adhesive material is packed into the horizontal space between logs, a process know as chinking. These walls are referred to as “chinked walls”. Chinked walls require continuous maintenance as the chinking is lost over time and must be replaced.
To reduce or eliminate the necessity for chinking, improved methods of log cabin construction have been developed. One such method involves logs with flattened sides and square notches. When stacked, the flat sides are closer together than rounded sides, minimizing the need for chinking.
The next evolution in log cabin construction utilized a scribing of one log of a wall to approximately match the contour of the log upon which it rested, thereby bringing the logs into more intimate contact. This intimate contact required only minimal chinking, or alternatively, caulking.
Additional developments to create better structural integrity and increased thermal efficiency have included flattened tops and bottom log surfaces to further increase contact surface area, and the addition of one or more tongues in one of the log faces to cooperate with and fit within corresponding grooves in the flat face of an adjacent log.
While these improvements have contributed to more structurally sound, energy efficient structures, other problems still remain. For example, logs which comprise the log structure tend to shrink in width even if they have been kiln dried prior to placement. This shrinkage, reported to be as much as 1 inch per log, contributes to increased draftiness and water leakage. Additionally, stacked logs settle as they shrink, reducing the overall height of the wall and thereby affecting the position of any structures supported by the wall. Such structures may include doors and windows which become out of square and roof trusses which become uneven.
Still another problem inherent in log cabins built by the above identified construction methods is the difficulty to effectuate major repairs to a wall section damaged by, for example, a fire or flood. Cutting out and replacing a section of damaged wall with acceptable cosmetic results is both labor and time intensive, with resultant high repair costs.
One construction method used to overcome both the shrinkage and wall section replacement problems is to utilize a wall panel comprising horizontal sections of logs stacked between and held in place by two upright support elements. Such an arrangement provides a means for supporting a load above the upper edge of the wall panel regardless of vertical movement between the upper edge of the uppermost horizontal log and the load and allows for relatively easy replacement of a damaged wall panel section.
One example of such a wall panel is U.S. Pat. No. 5,265,390 to Tanner. Tanner's wall panel comprises a base plate, a plurality of horizontally placed wooden logs independently held between a pair of standards and at least one jack mounted on the upper edge of each wall panel. The logs mate with one another without being fixed together so that each log can move separately relative to the standards.
While Tanner's wall panel presents advantages over non-panelized construction methods, problems still remain. Chief among them are the requirement to assemble the wall panel onsite. Accordingly, there is still a continuing need for improved methods to construct log cabins. The present invention fulfills this need, and further provides related advantages.
The present invention relates to panelized log home construction. In a first embodiment, a wall panel comprises a plurality of logs of predetermined length stacked on top of each other. A tongue is machined into each log end such that when stacked a wall tongue is formed from the aligned log tongues. A rod channel runs through the stacked logs for receiving a tension/lifting rod. A first end of the tension/lifting rod comprises a rod lifting attachment for lifting and a second end permits adjustment of the tensioning force. Optional protective channels fixedly cover each wall tongue and optional wall utility channels receive wires and pipes, as required.
In a second embodiment, a pair of posts fixedly attached to a foundation slidably receive the wall panels. Machined into each post is at least one wall receiving groove sized to slidably receive and cooperate with the wall tongue. An optional protective groove covering fixedly covers each wall receiving groove to lessen the possibility of post breakage upon wall panel insertion.
According to a third embodiment, a method of constructing a wall panel comprises the steps of stacking a plurality of logs of predetermined length on top of each other; machining a tongue into each log end such that when stacked a wall tongue is formed from the aligned log tongues; fabricating a rod channel through each log such that when stacked a rod channel runs through the wall panel to receive a tension/lifting rod, a first end of the tension/lifting rod comprising a rod lifting attachment for lifting and a second end permitting adjustment of the tensioning force; and placing a predetermined tensioning force on the stacked walls. Optionally, a protective tongue covering is fixedly attached to each wall tongue and optionally a utility channel is machined into each log such that when stacked, a wall utility channel is formed for receiving wires and pipes, as required.
According to a fourth embodiment, a log home comprises a plurality of wall panels and posts in a predetermined arrangement.
According to a fifth embodiment, a method of repairing a damaged wall panel comprises the steps of removing an effective amount of wall panel cover structure to permit the damaged wall panel to be slidable removed; slidably inserting a replacement wall panel; and repairing the wall panel cover structure, wherein the wall panel comprises a plurality of logs of predetermined length stacked on top of each other; a tongue is machined into each log end such that when stacked a wall tongue is formed from the aligned log tongues; a rod channel runs through the stacked logs for receiving a tension/lifting rod, a first end of the tension/lifting rod comprising a rod lifting attachment for lifting and a second end permitting adjustment of the tensioning force; and a pair of posts fixedly attached to a foundation to slidably receive the wall panels, wherein each post includes at least one wall receiving groove sized to slidably receive and cooperate with the wall tongue.
One advantage of the panelized log home construction of the present invention is the ability to easily and relatively inexpensively remove a panel section to repair major damage caused by, for example, fire or flood.
Another advantage is that the wall panel may be constructed off-site under controlled climatic conditions and then easily transported to the construction site.
Still another advantage is the reduced on-site construction time with concomitant cost savings on labor.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
The present invention will be described in relation to log homes. However, it should be appreciated that the materials described are not limited to wood. Any material suitable for construction may be substituted, for example, metal such as steel and aluminum, composites, extruded wood replacement materials and the like. Furthermore, the present invention is not limited to any particular wood shape or size, nor to any particular building shape. The dimensions described below are used merely as exemplars.
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At least one rod channel 20 is drilled into log 4 from first horizontal surface 12 to second horizontal surface 14 to receive tension/lifting rod 22 in stacked logs 4. Preferably two rod channels 20 are drilled at equal distance from the centerline of log 4. Optional utility channel 24 is drilled at a predetermined location so that when logs 4 are stacked, wall utility channel 26 is formed to receive, for example, electrical conduit, water pipe, gas pipe or combinations thereof. If required, utility slot 28, is cut into log 4 to receive, for example, an electrical box (not shown). Utility channel 24 may be cut horizontally into log 4, as required.
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To provide adjustable tension, tension/lifting rod non-lifting end 66 is, for example, threaded into nut 40 welded onto plate 68. Second nut 41 is threaded onto lifting end 23 and countersunk into uppermost log 4. Tension/lifting rod 22 is tightened to an effective force to create an effective seal and minimize cracking of logs 4. As required, electrical conduit, electrical wire, and/or pipe (not shown) is installed in wall utility channel 26, and electric box (not shown) installed in utility slot 28. Either bottom log 4 of wall panel 2 or base log 70 (
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It should be appreciated that prefabricated wall panels 2 may be constructed off site under controlled climatic conditions, thereby providing better quality control, tighter tolerances, and reduction in on site labor costs. Tension/lifting rods 22 and optional protective tongue covering 42 also serve to keep wall panel 2 from bowing as it is raised from a horizontal storage or transport position.
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Optionally, but preferably, protective groove insert 58, for example, a steel covering shaped to intimately receive protective tongue covering 42 is installed within wall receiving groove 52. Groove insert 58 is installed by, for example, drilling holes to receive ¼″ by 4″ screws 50 at 8″ centers. Screws 50 have tapered heads to maintain a flush or smooth finish to receiving groove 52. Prior to installation, seal 30 is placed under groove insert 58, in the manner described above.
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After installation of posts 48, wall panel 2 is raised by rod lifting attachments 62 and aligned such that tongue 6 (preferably protected by protective tongue covering 42) aligns with post groove 60 (preferably protected by post groove insert 58) and slidably lowered into place. Although wall panel 2 may rest directly upon foundation 76 or sill plate 78 (as required by local code), in a preferred embodiment, at least one base log 70, countersunk to receive tension/lifting rod nut 40, is mounted to foundation 76 or sill plate 78 (as required by local code) prior to placement of wall panel 2. Thereafter, wall panel 2 is slidably mounted as described above and rests upon base log 70.
Once wall panel 2 is in place, rod lifting attachment 62 is removed. If desired, tension/lifting rod 22 may be cut flush with counter sunk second nut 41. However, it is preferable to bore out the bottom log 4 of a second stacked wall panel 2, or the top plate 86, for example, a lentil log, as applicable, to accept the extended tension/lifting rod 22. In this manner, rod lifting attachment 62 may be reattached if wall panel 2 needs to be subsequently removed.
Maximum wall panel 2 dimensions are limited only by the ability to transport, lift and position wall panel 2. Wall panels 2 may be stacked utilizing, for example, dowels 74 or pins, and adhesive bead 32 with a through lag bolt or screw (not shown) from the opposite side of post 48 installed into stacked wall panel 2. Posts 48 may be likewise stacked using for example, dowels 74 or pins, and adhesive bead 32. As shown in
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A plurality of wall panels 2 and posts 48 placed in a predetermined pattern form the log home (not shown). By utilizing the panelized log home construction of the present invention, onsite framing time has been reduced from six to seven months down to five to ten days. Similarly, the time required to replace a damaged wall section has been dramatically reduced.
To repair a damaged wall section, the roof and overlying floor (if present) are cut away a sufficient amount to allow wall panel 2 to be lifted out after cutting the appropriate adhesive bead 32 and replaced with an undamaged or repaired wall panel 2. If a repaired wall panel 2 is used, a replacement tongue 6 is added, if required. Rafters and joists that have been cut away to provide lifting access are repaired using known “sistering” or similar construction techniques, followed by repair of the floor and roof.
Although the present invention has been described in connection with specific examples and embodiments, those skilled in the art will recognize that the present invention is capable of other variations and modifications within its scope. For example, in the exemplar, protective tongue covering 42 and protective groove covering 58 are utilized to prevent breakage of post 48 during installation of wall panel 2. However, depending on the strength of construction materials used, one or both could be omitted.
These examples and embodiments are intended as typical of, rather than in any way limiting on, the scope of the present invention as presented in the appended claims.