How to Lay Out a Log Stairway

Lay Out the Stringer End Cuts

• 1

  Lay the fist stringer log in a horizontal position, measure its diameter and put a pencil mark on top, that is a diameter's length from the log end.

• 2

  Tack a 1 inch brad into that mark, tie a chalk line to the brad and extend it around and under the log to the center-end of the log. Hold the line with one hand and trace it with a marker, defining a straight cut-line over the curved surface. This is the cut-line that will produce the flat-lying bottom end of the stringer when it is lifted into place.

• 3

  Construct a 45-degree stringer elevation jig from a 3-foot square piece of cardboard. Connect the diagonal ends with a straightedge and cut out the jig. This procedure yields two identical jigs.

• 4

  Lift the first stringer log onto the landing surface at its intended tie-in location and extending at least a foot above it. Hold the stringer elevation jig at ground level and move the log until its elevation angle is 45 degrees. Rotate the log until the bottom-end brad is exactly at its lowest possible underside point.

• 5

  Drop a plumb line from above the stringer, touching the outside vertical edge of the upper landing surface and mark the spot on the top and bottom of the stringer where it encounters that line. Tack brads at those points, connect the brads with chalk line and trace the line with the marker. This cut-line defines the top-end vertical construction surface which is tied into the landing surface with bolts, brackets or additional substructure.

• 6

  Repeat the stringer end-cut layouts on the second stringer.

Lay Out the Stringer Tread-Cut Notches

• 7

  With the stringer still resting on the upper landing surface, measure and mark a spot on top the stringer every 12 inches from top to bottom.

• 8

  Drop a plumb line from above the first (upper) point and mark the spot where the line reaches midway through the stringer. Mark this spot, connect it to the topside point with brads and chalk line then trace it with the marker, producing the vertical cut-line for the top tread (step) notch.

• 9

  Hold a level at the midpoint mark and draw a cut-line from that point to where it runs out on the upper surface of the stringer. This is the horizontal cut-line for the first tread notch.

• 10

  Repeat the tread notch-cut procedure for all the remaining treads in the stringer.

• 11

  Lay out the tread notch-cuts on the second stringer.

Lay Out the Tread Cuts

• 12

  Measure the width of the landing surface edge that was allocated for the stairway to connect at to determine the length of the treads. Allowing for the diameter of the stringer plus 3 inches on each end of the tread -- for decorative overhang -- determine the inside distance between the stringers and the length of each tread flange (Note: a tread flange is an overhang lip at each end of the tread that allows the tread to lie flat in the tread notch.) For example, a 5-foot long tread resting on 10-inch diameter stringers, would force an inside stringer measurement of 34 inches -- 60 inches minus 26 (10 + 3, or 13, times 2 equals 26) -- and 13-inch flanges on either end of the tread.

• 13

  Determine the number of treads needed by counting the number of 12-inch marks on the stringers. On a new log(s) measure and mark the cut-points for each pair of half-log treads (each crosscut of the log yields two, ripped treads).

• 14

  Draw a line all the way around the log at each crosscut point with the chalk line technique. Tack brads into the horizontal midpoints on both ends of the log, stretch a chalk line tightly between them and scribe the horizontal cut-line all along the midpoint of the log. This defines the overall cut-lines for all the tread blanks (unfinished treads) that are cut from the log.

• 15

  At the intersection of a crosscut line and the horizontal cut-line on the log, lay out the tread cuts on the lower tread blank by drawing a line parallel to the center line of the log, 2 inches below it and extending into the tread blank. The length of the line is the diameter of the stringer plus the overhang.

• 16

  Tack a brad into the inside endpoint of this line and scribe a cut-line around and under the log to the backside midpoint of the log. Tread cut-lines marked in this way will produce notch cuts in both ends of each ripped, half-round log section, leaving a 2-inch thick flange that rests flat in the tread notch of the stringer while allowing the underside between the stringers to be half round and rustic.

• 17

  Repeat the tread cut-line layout procedure for all the remaining tread blanks in the log, remembering that the upper blanks in the log -- when viewed horizontally -- are then upside down. When the log is crosscut, ripped and notched according to the lines scribed the stairway components will be finished and ready for assembly and hanging.