Tinyo Stair
Laguna Beach, CA
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My client, an Orange County architect, asked for some help with replacing an existing two story interior spiral stair. There were several challenges including:
- The floor to floor heights were different
- The first floor stair consisted of 1-1/4 turns
- The second floor consisted of a full turn
- While two sides were solid walls, the other two were open, one open to the living room and the other open to a window with a view of the ocean
- The architect indicated that the stair would be stained and not painted
The goal was to use the risers as structural members, spanning between the center pipe column and extending out towards
the supports. The supports on the open sides would be provided by using steel tube sections, mitered to follow the stair run.
Since the framing members were going to be exposed, I chose to use birch for the risers and 3/4" birch plywood for the treads.
One edge of the tread would be supported on the riser below and the other would be attached to the bottom of the riser above.
I set up a spreadsheet which would determine the riser heights. The riser height for each floor were slightly different as the
floor to floor heights were different and the rotational difference (1-1/4 turn for the first floor and 1 turn for the second floor) were different.
Knowing that the actual floor to floor heights may be different than the nominal values provided to me by the architect,
I set up the spreadsheet to determine the net riser height, taking into account the tread thickness) for each floor. That way,
when I received the actual floor to floor heights, I could adjust the riser heights accordingly.
I also set the dimensional tolerance to 0.001" so that it would fit.
I also used concealed connections at the ends of the risers and tube stringers.
The architect and owner were quite pleased with the results.
