The clients wanted a nice stair case, the lady of the house went back to the memory of an impressive concept her father used to build, as a contractor in Pampanga. It involved cantilevered stair treads made from then plentiful hardwood, which was poured in place together with the adjacent wall. This time instead of 1 meter wide stairs, they wanted 2 people to be able to go up and down, while being strong and safe.
Automatically I thought of making it in steel and cladding it simply, hiding the structural acrobatics within (and any imperfection along with it), and as a nod to the original concept of wood planks, we would top the treads with recycled wood.
Our engineer used steel flanges, steel plates with stiffeners to come up with a tread and stringer that we hoped would be stable, and we incorporated a simple railing with tempered glass panels for safety and support while going up and down.
After getting approval for the details using a 3D perspective of Google Sketchup, we waited for the concrete structures to reach their maximum strength (on the 28th day) before getting down to the welding of the main stringer.
We found that it would be better to support the first flight from the exterior wall instead of immediately upon the landing to make it more graceful. But, we found the treads unsteady as it vibrated while we went up and down, so additional vertical reinforcements were done to stiffen the main stringer and the tread was made into a box beam for further reinforcement.
After completing the final run to the 2nd floor and all the structural details, it still vibrated a little as 2 people used it, though fortunately this would solve itself as we proceeded with construction. Primer was applied and preparation was made for the installation of wood planks.
The main stringer and the treads were closed off to give a less “industrial” look and a simpler profile for the stair. To stiffen the main stringer more, a short column was placed a third of the way from the main stringer. And to make the stair color float from the wall “gun metal grey” was chosen.
Wood was requested to also clad the side of the tread (the riser side) so that as the user would see just wood going up. Tempered glass was chosen because its stronger than ordinary float glass, as well as it was safer, because it didn’t become shards when it shatters. We also found that any vibration that was still evident during the fabrication and testing of the steel frame was removed by the installation of the wood plank, which now acted as a stiffener to the tread.
The right side railing on the first flight was removed in favor of a more impressive look, so that the cantilevered treads of the second flight could be more readily seen, hand rails were also installed on the stainless steel railing frame. All the wood was then sanded and finished in semi-matte polyurethane finish.
I have yet to get a dedicated picture of just the stairs, but here it is seen with the rest of the space. It was designed as ‘welcome’ element coming in from the main door, impressive as it is useful.