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The staircase for this house built for young professionals, was to be modern, fresh and exciting, but simple, elegant and sturdy for sometime.  With the help of our interior designer and structural engineer we were able to have a design that answered all the requirements of the program.

Our design solution was inspired from a steel frame business type access stair, which we decided would be used as a overlay of the reinforced concrete stair that was planned for the house.  Making the statement was the zigzag form that the tread and risers would take, further made interesting by a horizontal railing design that would be completed by a wood and metal hand rail.

Architectural drawing and 3D model of Zigzag stairs

Our initial difficulty was that the structural design was in the conventional manner, that was a solid with the risers and treads only seen formed from above, and a plane incline below, to follow the zigzag form literally would make the lines too thick as it would not support the load.  We wanted as thin a line as possible for the zigzag.  The solution was to pull back the concrete slab from the edges, just enough to create the profile we wanted but without making it too weak that it would crack, or too thin that it could not carry its weight and as well as the live loads.

Stair cross section and structural detail

The next challenge was regarding the look from the top and the budget.  A zigzag pattern should have a continuous finish on the tread and the riser, setting planks for the treads would mean planks on the riser which after confirming with the client, would be beyond what the budget would allow, so we made use of plywood on the risers and found a way to use casing to hide the thickness of the planks so that from the side it would seem that the treads and the risers had the same thickness of material.

Zigzag stair isometric detail

The clients approved of the scheme among the number presented and the interior designer gave particular instructions regarding the finish and the look.  We went into its construction shortly after.

Forms for the concrete stairs are done as exterior molds of the form, and it was interesting to see the inclined mass flanked by 2 stair like molds.  After the concrete was poured, and the forms removed, the initial stair form was realized.

For the railing to be successful, the stair treads were measured as basis for fabrication, the design composed of round bars & flat bars were then painted in grey epoxy paint for protection and installed to the concrete stairs.

Stair railings delivered to the site.

Installation of the railing to the concrete stairs.

Wood planks, plywood cladding and casing were installed in such a way as to make the wood seem consistent with the zigzag form, as well as to hide the flat bar connection between the stair and the railing so that the design would seem to be projections of the zigzag design.

Wood plywood and planks installed.

The minor details would  prove to contain the delightful characteristics of the construct.  From the  landing termination, hand rails and the zigzag baseboards, these elements would help support the over all concept.

Detail of railing at the landing.

Baseboard trim installed where the stairs meet the wall.

Hand rails are installed on the flat bar supports.

When all the components were installed and ready to accept final finish, we had the client and the interior designer approve the color, and texture of the wood, as well as the metal railing. All of these choices were done to complement  the over-all color scheme of the house.

Dark grey color for the metal railing.

Wood planks and hand rail were done in a matte finish as per the interior designer’s instruction.

In the end it came out better than expected and would be a centerpiece for the house interior.

View from the ground floor landing.

View of the stair from the midway landing.

View of the ground floor stair and the lower level landing.

View of the stair from a low vantage showing the railing termination.

Detail of metal railing with termination at a column post.