The Timber Frame House - Part 2
Of all the projects undertaken here on the hill, the house is the granddaddy of them all. Completion of this task was measured in years, not months. True creativity is a rare gift. I am quite certain that I have never had a truly original idea, but rather I am a grand imitator, altering a nuance of an old design and calling the whole mine. A fortuitous trip to Sturbridge Village in Massachusetts introduced me to the beauty of early American timber framing and from that moment forward, I was determined to build my home in this tradition.
By good fortune I discovered the availability of 200 recycled Douglas fir timbers (8x8’s and 6x12’s) in Leavenworth, Kansas. This was Great Find #1. After striking a deal, I hired the largest flat-bed tractor trailer with driver available. At the end of a 16 hour expedition I had timbers scattered along 100 yards of our snow laden country road. Using a homemade sled and my four wheel drive pickup, each timber was singularly skidded up the ridge and staged. My future home lay unrevealed within several large stacks of timbers.
The heart of a timber frame structure is the bent, a truss spanning the width of the house and standing from floor to roof peak. The bent is assembled horizontally on the ground using mortise and tenon joints held together with wooden pegs and is then raised into an upright position. The actual lengths of my stock dictated the overall dimensions of the bent design. The number of 22 foot long 6x12’s in my collection determined the maximum bent width using 12/12 pitch rafters (rafters angled at 45 degrees). Overall, each bent would measure 24 feet wide and 24 feet tall. Over time, seven individual bents would be assembled and raised to establish the 65 feet of house length.
The blueprint for my design was never more than sketches on grid paper. To derive actual dimensions I used the basic 3-4-5 rule or Pythagorean’s Theorem. The accuracy of each member of a bent is extremely important. As discussed in the Pavilion project, mortises or square holes are formed using auger bits, framing chisels, and mallet. Tenons are formed by a series of kerf cuts using a circular saw and then pared off with the framing chisel. The slick (a long handled chisel-like tool) planes the joint surfaces to a mirror finish. Each member of the bent is constructed in the work shop awaiting assembly at a later point.
A typical house wall is constructed using 2x4 or 2x6 dimensional studs with a sill plate. The sill plate applies a continuous load bearing surface to the foundation. Timber framing uses a post and beam design, meaning all loads are transferred through individual posts (point loads applied to the foundation). Therefore, my concrete basement foundation and footings are oversized with abundant rebar (iron rods) positioned strategically at each post location. My frame weighs significantly more than a typical home.
The rafters, posts, beams and collar tie within the bent are full dimension stock as purchased. However, other members of the bent require smaller sizes. The stock for queen posts, braces, purlins, and struts were cut from 6x12 timbers using a long bar chain saw, a special rip chain, and a fixture to control the cut. Ripping (cutting with the grain as opposed to across the grain) a long timber with a chain saw is not a quick and easy job but it does work. Once the new timber was smoothed with an electric hand planer, the joinery work would follow.
Great Find #2: An air force base was dismantled south of Kansas City. I chanced to spot a truck laden with some of the material, pursued the driver, and discovered the source. A deal was struck and from that demolition project I obtained 100 – 3”x14”x24’ planks to be used eventually as flooring; 150 – 2”x12”x14’ boards for joists, and several thousand feet of 1”x6” boards. The small company that demolished the building also excavated for our foundation. After the floor joists were installed, temporary flooring established the working platform to erect the bents.
The first bent I assembled is called a hammer beam truss. This design incorporates only two posts, which enable an open living area between the posts. The end of the foundation was centered directly in line with a large Shagbark hickory. High in that tree several pulleys were installed. Cables were connected to strategic points on the assembled bent, passed through the pulleys, and routed downward to “come-a-longs” chained to other trees. Large chain links were spaced in the cable every four feet from the end nearest the pull-tree. Because a “come-a-long” has only about four feet of travel, a second “come-a-long” can be installed grabbing the next link and the first removed and repositioned as the pull continues.
An essential tool in the early years was the block and tackle. Ropes passing between multiple pulleys provide a mechanical advantage to increase the lifting forces. While this tool accomplished significant work, it could not unassistedly hold a load in place. The invention of the “come-a-long”, though similar in design, not only increases the mechanical advantage but can be physically released while the load is sustained. The pulling force of this tool is also used to apply great compression of the joints within the bent prior to pegging.
The initial pull creates a tremendous horizontal force at the base of the posts, which tends to slide the bent off the foundation. That horizontal force decreases to zero once the bent is raised perpendicularly. Therefore, to assist in the early portion of the raising, “gin” poles are employed. The gin pole is a post with a pulley attached at the top. Using a “come-a-long” secured to the base of the pole, the gin pole allows a straight vertical lift to develop a more favorable angle of the truss. As the bent is raised, the gin poles are removed and the lift continues with reduced strain on the cables.
Neighbors assisted on “raising day” to crank the “come-a-longs,” while I provided instructions to each individual. The bent must not be allowed to “hinge” at the post & rafter connection, which might destroy the joint; the bent must remain in a flat plane. As the bent reaches plumb, a previously attached tag rope is secured to prevent the bent from falling over in the opposite direction. With a great sense of relief the first bent is temporarily stabilized with lumber and a cold beer is in order for all.
In the early years, bents were raised with the power of many men. As the peak of the bent lifts higher than a man’s reach, a “pike pole” was inserted (a long pole used as an extension to apply force). Poles of various lengths were required to continue the lift. Obviously, if enough poles slip away, the bent could be lost and would crash down on the hapless lifters. The use of the “come-a-long” is not only effective but positions the helpers away from danger.
For the next raising day, pulleys are placed in the standing bent as well as the pull tree. The second hammer beam is hoisted up in like fashion as the first. As the bent approaches perpendicularity, the connecting timbers or “girts” are hoisted up along with their braces to receive the joint. Thus ensues a “dance of sorts” to initially start the girt tenons into their mating mortises, such that the joint is firmly seated when eventually the bent stands vertically. Pegs then secure the girts and braces in place. Dovetail pockets have been previously mortised about four feet apart in the top surfaces of the rafters. Into these pockets are seated the 6x6 “purlin” timbers that tie the opposing rafters together. Once the purlins are installed, a stable structure exists without worry of collapse. The project could be terminated at this juncture resulting in a one room timber framed house.
Six of my seven bents have the same external dimensions yet each is uniquely designed to fit the floor plan of the house. Bent #3 differs from the first two by virtue of its four post design, which supports the upper floor. This bent boasts one noteworthy circumstance: it was raised upward and over, crashing into the standing hammer beam trusses. I will forego the excruciating details that created this disaster other than to say with humility that “adversity breeds character.” Building the same bent the second time around was not nearly as much fun.
During this period of building I maintained a full-time job. The frame was just a side project with no deadline. I was consumed with the joy of a spectacular project and the completion of the frame was not an imperative. After all, I was single and had my shack. What more could a man ask for? After the raising of the hammer beams, I was back in the shop manufacturing the timbers for bent #3. Many weeks would transpire before the raising dates of subsequent bents. Over a period of two years, six large bents were raised and then a half sized bent was the final #7.
Bents #1 and #2 used only outside girts to tie the bents together. Beginning with #3 through #6 Internal girts were also necessary to provide a bearing surface to carry the load of the upstairs flooring. The “dance” becomes more complicated when up to 6 girts (6x12’s) must be lifted and coordinated simultaneously to find their final seat as a bent is raised. Some of these girts hold adjacent bents with dove tail joints rather than pegs. Smaller 6x6 joists are “let-in” to the just installed girts to create a complete joist system. The upstairs was now readied for flooring.
Bent #7 is only 12 feet wide, not 24 feet. This bent (as with the hammer beams) established a vaulted area (no upper floor) to serve as a small dining room. Following the successful raising of #7, the timber frame was complete. The structure as designed is a house but could just as well be used as a barn. I realized that once I began enclosing the structure, I would never again have the opportunity to cleanly view my completed frame. I paused in the construction for a short period to be steeped in the beauty of the frame. It wasn’t a masterpiece but I was proud of it. Now my mind’s eye no longer carried the burden of bringing Sturbridge, Massachusetts to Pleasant Hill, Missouri.
Great Find #3: In the manufacturing plant where Gayle and I worked, a redwood cooling tower (built in the 1940s) was demolished. In a closed bid I obtained (with minimal expense) thousands of board feet of 2x6 tongue and groove redwood. This material would ultimately become the ceiling boards and the outside siding for the entire structure. These boards were passed through a planer and then beveled at the edges with a table saw. One trip up the extension ladder marked one more board applied to the roof. The tie between our place of employment for 37 years and the utilization of this material in our home was very satisfying.
With all the roofing boards installed, two porches were added to the frame, separated by a garage. The front end of these porches required small bents, which were raised in typical fashion. Thereafter, the garage was built using conventional lumber, incorporating timbers for the girder and door headers. Because the area above the garage was to be a bedroom, timbers were utilized as rafters to integrate harmoniously with the frame. Generous 8’ wide dormers made the room practical. The subfloor of this room consisted of recycled 1x6 lumber. Later, oak flooring from the original air force barracks completed the floor surface. Redwood boards were applied to the garage roof and 1x6 boards roofed the porches and siding for the garage gable end.
For roofing insulation, rigid foam panels (4’x 16’ x 8”) were lag screwed into the redwood and timbers. A make-shift ramp and ridge pulley allowed these 175 pound panels to be hoisted up without assistance. Roofing underlayment and shingles were applied directly on top of the rigid foam panels. Nine large skylights and a large complement of windows face the southern exposure. For Gayle and me sunlight is health and joy, both mentally and physically. An unobstructed view of the forest is for the joy.
Because of the extra thick foundation, space was available to provide the bearing surface for a conventional stud wall. Unconventionally, our walls are not designed to support a load. The only purpose of the walls is for the attachment of siding, windows and doors, and to provide a cavity for insulation. The stud wall is shimmed away from the frame leaving a ¾” gap between the walls and the frame. This gap provides the clearance necessary to install sheetrock by sliding it behind the timbers. With the sheetrock tucked securely behind the frame, we avoided the use of inside molding that would be distracting. A foam panel was then applied to the outside stud wall and the redwood boards completed the siding. Other redwood (reclaimed from another project at work) was installed at the gable end of the garage and also used to make the garage doors.
Recognizing my limitations, I hired a local stone mason to build two chimneys, one at the gable end and one three-flue chimney inside. These flues serve a built-in fireplace, a free standing stove, a wood furnace in the basement, and the hot water tank exhaust.
The massive 3x14 planks salvaged from the barracks were installed both upstairs and down as flooring. The planks were screwed and plugged to the joists, sanded, stained, and finished. The ever moving cracks between the planks were filled with stained upholstery cording. The upstairs flooring and downstairs ceiling are one and the same. Thus, the space between each plank needed to be filled to avoid unwanted debris filtering through from above.
Great find #4: Mature oaks, hickories, ash, and walnut trees do eventually die. Many of those beautiful logs have been towed to our one man saw mill and rendered into boards. All window & door trim, and baseboards are full 1” thick hardwood. The inside walls of the garage are also paneled in wide oak and hickory planks. It is difficult to build a very unique home with materials bought from Home Depot. The discovery and application of these unique building materials was a godsend. Sometimes good fortune just happens and for that we are grateful.
By resisting the urge for instant gratification, and maintaining patience and persistence, we now have a comfortable and unique home. No mortgage was ever required to fund the project. Therefore today, Gayle and I direct our expendable resources into our gardens and landscape. Whether designing and building a home or designing and constructing a garden, the joy of applying personal creativity to projects is very rewarding. Extraordinary talent and intelligence is not a requirement. Just the satisfaction of viewing your accomplishments with pleasure and pride is the reward.
Today, I view the home as just another extension of Hosta Alley. Gayle and I have a comfortable base to continue our expansion of the gardens. All that is here: the buildings, the statuary, the walkways, even the barn, are crucial to further the advancement of our gardens. I could have never imagined those many years ago that one singular plant would have such influence upon my life. Gayle and I are indeed blessed to live out our remaining years here on the hill.
The Timber Frame House - Part 3
The Timber Frame House - Part 1