Timber frame construction has historically referred to buildings whose supporting structure was made from rough, heavy beams joined by carved, woodworked joints. Today, any structure made from heavy lumber is often called timber frame. Cabins using the timber frame post and beam or similar types of construction are simple to build because the frame construction is straight forward and the walls can then be filled in with any material that is available. Using beams made from trees on the property where the cabin will be located greatly reduces the cost of the structure, but such logs are more difficult to work with.
Place stakes in the ground to indicate the corners and walls of the cabin. Place stakes where the concrete support columns will be located. Typical spacing is every 4 to 8 feet. The distance depends on the carrying capacity of the beams, which will have to carry the weight of the cabin and contents across the distance between the columns. For larger cabins, columns down the middle of the cabin may also be required.
Dig or drill holes at the location of the support columns determined in Step 1. These holes will contain the concrete columns to support the cabin. The holes must reach below the frost line and be stable. For the southern United States, the holes might be 2 feet deep while in the north they may have to be 5 or 6 feet deep. For shallower holes it is easier to dig, while for deep holes it is easier to drill holes the size of the columns that will be placed there.
Place cardboard tubes, often called sonotubes, into the holes. Tubes of 8 inches to 12 inches will be large enough. Level the tops and brace them securely. Fill the holes with concrete. Place bolts with the heads down into the concrete at the top of the columns so that the beams can be fastened to the concrete columns once the concrete has hardened. The bolts should be placed so that the edges of the beams will be level with the outer edges of the concrete columns.
Place beams across the concrete columns around the edges of the cabin and across the middle to support the floor. Attach the beams with the bolts placed into the concrete. Join the beams with wood joints, such as mortise and tenon, or by using metal fittings with plates and bolts. Place additional supports for the floor inside the rectangles formed by the beams using dimensional lumber. Supports of 2 inches by 4 inches or 2 inches by 6 inches on 16-inch centres should be sufficient depending on the sizes and spacing of the beams. Cover the supports with plywood that is at least 5/8 inch thick.
Build the front wall of the house. The front wall will have the front door and will eventually be peaked to support the roof. Construct a rectangle of beams lying down on top of the floor that has just been completed. The length of the rectangle is the length of the floor and the height will be the height of the cabin, perhaps 8 feet. Join the beams with wood-worked joints or metal fittings. Add angled braces into the rectangle corners for strength. Raise the wall into place with helpers or a pulley system and place temporary braces to keep it vertical. Repeat this process to construct the back wall.
Join the front and back walls installed in Step 2 with the beams at the top and bottom to form the side walls. Place the beams at the top over the front and back walls so that they protrude by about 2 feet to allow for the roof overhang since the roof trusses will be placed on these beams.
Insert vertical beams and angled braces as needed to give a solid structure and support the inside and outside finishing. If the walls are 8 feet high and the beams are placed on 4-foot centres, it will be easy to clad the walls with 4-foot by 8-foot panels of plywood and gypboard. If the beams are placed with 4-foot spacing, it will be easy to place plywood and gypboard panels between the beams, leaving them exposed for a rustic effect.
Construct a roof truss in the shape of a capital "A." The horizontal line of the "A" will be the width of the cabin and fit over the top of the side walls. For areas with no or light snow load, the "A" can be fairly flat. For heavy snow loads, the angle at the top of the "A" should be 60 degrees or less.
Place the roof truss flat over the side wall beams and the raise it into place with helpers or a pulley system. Position the truss at one end of the beams where they overhang the walls. Check for fit and visual appeal of the design. Construct and place the rest of the trusses and cover them with plywood. Trusses on 24-inch centres may have plywood at least 5/8-inch thick nailed directly onto the trusses. Trusses spaced further apart will require filling the spaces with dimensional lumber for support.
Install roofing tiles or shingles. Tar paper and asphalt roofing shingles are inexpensive and come with detailed installation instructions on the packages. Wood, clay and other roofing tiles are also available, as is metal roofing.
Frame in windows and doors between the beams. If commercially available windows and doors are to be used, they should be selected first so that the framing is done with the proper dimensions. Framing for homemade windows and doors can be put in place and the windows and doors constructed to fit.
Finish the outside walls. Install dimensional lumber framing between the beams as required for support for the finishing material. If the beams are left exposed, all joints must be carefully sealed or covered, especially at the bottom of the cabin where the floor meets the concrete supports. If the beams are covered, the outside wall finishing should extend down just past the bottom of the lowermost beam to keep the floor and concrete column tops dry.
Finish the inside walls. If gyprock is used and the beams are on 24-inch centres or 16-inch centre dimensional lumber has been installed, plastering can be avoided by nailing sections of beams over the gyprock joints to simulate exposed beams. This is especially effective for finishing the roof. Other interior finishing materials such as panelling and wood boards require additional support with dimensional lumber between the beams. Often the supports installed for the outside finishing can be used.
Paint, stain and finish with mouldings as desired. A cabin made with beams in this way is modular and can easily be expanded by adding to the front or back.
Things you need
- 4-inch by 4-inch beams
- Bolts (optional)
- Plates (optional)
- Roof tiles