Two young friends have lofts in their rooms and they were in need of a permanent way to access them. After visiting to take some photos and measurements, we decided on seventy-five degree ladders with treads about six inches deep and eighteen inches wide. We also planned to use 1-1/4 inch thick poplar, to match the existing woodwork leading to the entrances of their rooms. In keeping with the existing woodwork, we chose a Bona Traffic HD anti-skid floor finish, a waterborne two-part finish that would let the beauty of the poplar show through and be very durable.
While a seemingly straightforward project, a few factors made these ladders a bit challenging. Vertical dimensions to the lofts were 107-1/2″ and 108″ respectively, so the stringer boards were over nine feet long. For strength, the eleven 1-1/4″ thick treads per ladder were designed to be let into 1/4″ deep dadoes on each stringer, and secured with four 2-7/8″ HeadLOK timber fasteners each. Machining these dadoes, evenly spaced and at 15 degrees from the edges of the stringers, called for a custom router jig which worked well, until the stringers were compared and a small amount of cumulative error was discovered. This resulted in some adjustment cuts, some custom filler strips and a lesson (re)learned about the stackup of tolerances.
In hindsight, one stringer should have been machined with the router jig as described above, then the dado locations should have been transferred to the matching stringer. The router jig should then have been positioned according to the transferred locations. This method would have resulted in the dadoes matching from stringer to stringer … the first time!
The photos below will illustrate the steps in this project, including the correction of cumulative error due to the stackup of tolerances using the router jig!
Two notes: The cumulative error mentioned above, and the resulting cosmetic fix had no impact at all on the structural integrity of these ladders. Also, handrails will be designed, fabricated and installed before my young friends are officially released to use their new loft ladders!