Be sure wood is dry. Material from a job site or floor joists that existed in a crawlspace may have high moisture content; material from a conditioned space should be dry. Wood can be dried in a kiln (ask your local lumber mill) or stored inside through the winter. If time does not permit, stack wood in a hot dry place with 1" spacers between layers. Allow to dry for a minimum of two weeks.
Rough-cut boards to the desired length, plus 2 inches. A final cut will be done after the planks are joined.
If planks are slightly cupped or twisted, have them planed at a local millwork shop or borrow a tabletop planer and tackle the job yourself. If planing yourself, first check planks for and remove nails and excess dirt*. Run planks though the planer, stripping a small amount of wood from each side as you plane. While the board is going through the planer, manually adjust the depth of the cut to compensate for irregular thickness (or twist) over the board’s length. You can hurt yourself or damage the board or planer if you do not manually adjust as you go. Keep running boards through the planer until the blade has lightly stripped each surface. Next, rip boards on a table saw to create straight edges; planks do not have to be identical in width.
Some shops may decline this job to avoid damage to blades from concealed nails and/or embedded dirt. If no other options exist, sand the tabletop with a wide-belt hand-held sander after planks are joined. Keep belt perpendicular to plank joints and move back and forth in a direction parallel to joints.
The top of the table shown was fashioned from old, rough-sawn 2"-thick 2x12s. Rafters and floor joists from renovations and demolition jobs would work just as well*. Make sure to carefully pull nails and staples first.
Two old symmetrical porch columns were cut in half to make four legs. Wooden gutters were used in place of crown trim to cap the table's perimeter.
When sourcing materials from a renovation or job site be sure to have clear permission and wear the appropriate safety gear. Be aware that lead paint and asbestos may be mixed in with clean wood. Watch out for and pull nails out of material before loading in a car or truck so reclaimed wood will stack better. Be careful when working with items painted prior to 1979 as they may contain lead-based paint. Be sure to consult the EPA's Renovate Right: Important Lead Hazard Information for Families, Child Care Providers, and Schools pamphlet before disturbing any paint that could contain lead. Building materials produced before 1983 should also generally be tested for asbestos. Contact your local building official for exact requirements.
Clean wooden gutters of any loose debris and cut to a manageable length. Miter down to form an approximately 40" x 94" rectangle. Coat the corners with wood glue and fasten together with 15-gauge finish nails. If miters are tight 45-degree cuts, box should be square. Double check diagonal measurements before fastening completely. The two diagonal measurements should be as close to equal as possible.
When complete, set the box on a clean, flat surface. To form legs, cut the antique column in half at the center line of the profile and then trim them to a length of 34 inches. To cap the top of each leg, cut walnut flooring scraps to size and attach pieces to the tops of legs with wood glue and 18-gauge finish nails. Measure thickness of the top.
Set biscuit joiner depth to #20. Lay the four best planks out on a flat surface and arrange them in final position. With a pencil and working across two boards at a time, make a mark at every 8-inch point along the seam of two boards. After marks are made, use the joiner to cut the biscuit slots at each location. Align the reference mark on the tool (similar to circular saw) and hold the top plate firmly flat against the board. In one smooth motion, plunge the tool until it hits the stop. Note: Do not cut joints on outside edges of first and last board.
After all slots are cut, stand each board on end and coat the edge of jointed side with wood glue. Next coat the biscuits with glue. Insert biscuits in one side only of each board, then insert glued biscuits in the empty joint of the next board. Assemble planks in order until the top is complete. Don't worry about small gaps. Next, carefully lay the top down and attach pipe clamps at roughly 1' intervals. Slowly tighten each pipe clamp in a consistent fashion until the gaps disappear*. Small amounts of glue can be removed when dry; scrape up any puddled glue with a plastic putty knife. To minimize sanding later, avoid working glue into the top of the wood. Let the top set overnight.
Once the top is dry, remove the clamps from the top and check for relative flatness to the assembly. Use a small hand-held planer or razor to remove any dried glue. Mark each end 1/2" in from the shortest board and make a clean perpendicular cross cut.
Do not over-tighten the pipe clamps as the top will eventually bow. Clamp a cross piece of 2x4 (perpendicular to the planks) before fully tightening the clamps to keep planks flat during the drying process.
While the top is drying, measure the thickest portion. Add 1/16” to this measurement and mark a horizontal line with a framing square across the tops of the table legs. This line marks the gutter structure mounting depth. Legs will protrude 1/16” above the plane of the tabletop. Ask a helper to hold the leg tight to the inside corner of the gutter structure with the mark at the top of the gutter. Drive at least two wood screws through the inside face of the gutter into the sides of the leg.
Attach all four legs and set the top on the base with equal overhang on all sides. Carefully trace the leg tops on the bottom side of the planks and then flip it over onto a work surface. Drill a 1/2” hole with each square mark near the line but not touching it. Using a jigsaw, carefully cut out each square. Because leg tops will nest snuggly in these squares, be sure cuts are slightly undersized. Flip the top back over and attempt to set it on the base. Using a flat wood file and chisel, remove small amounts of material as needed. Once the top nestles down on the gutter structure without excess force, run a small bead of wood glue on the top edges of the gutter, reposition the top and shoot 15-gauge finish nails through the inside edge of the gutter into the bottom of the tabletop. Fill in small gaps between the leg top and table planks with wood filler or small wood shims.
Using an orbital or belt sander, carefully sand down the tops of the legs (1/16" high) until even with the top. Sand any rough spots or glue marks. The table, gutter and legs can now be painted, stained, polyurethaned or waxed. Walnut-tinted furniture wax was used to finish the table shown. Apply several coats of wax over the course of several days to fully saturate the wood grain.