The glass is tempered, yet not load bearing. There is a steel structure hidden within the stair construction.

Thanks so much for answering. We love it so much, one more question. Is the white side of the stairs sheetrock or something else?

The white stringer on the sides of the stair is painted poplar. With this kind of stair setup, you need something that has some strength but also some teeth to it for the fasteners. So the poplar conceals the wood and steel framing within the stair construction. Another reason we like using poplar is its a great wood for painting and its more cost effective than other hardwoods. Hopefully this helps.

How did you get the wood on the treads and risers of the stairs to be square-edged instead of rounded? Is there a specific brand of wood plank that you used that comes this way? Also, is this solid hardwood or engineered wood?

The treads and risers are solid, white oak. Stair manufacturers create square or rounded edges on both components to accommodate design needs.