Sunday, February 3, 2013

Stairs

Unless stairs are hidden away, they cannot help but be a visual focus. And a modern, custom built home is pretty much required to have visually intriguing stairs. As far as we can tell, building the stairs is also required to put the house behind schedule. Our home is no exception on either count.

We consciously chose to push the stairs into a prominent position that made them more functionally and visually central. The process of designing the stairs differed from much of the rest of the house. We were deeply involved with most elements of our home. For the stairs, we provided some inspiration pictures and some input, but largely trusted our builder to come up with something we would like.

Staircase as a Stage (133)
  • Problem: A staircase is not just a way of getting from one floor to another. The stair is itself a space, a volume, a part of the building; and unless this space is made to live, it will be a dead spot, and work to disconnect the building and to tear its processes apart.
  • Therefore: Place the main stair in a key position, central and visible. Treat the whole staircase as a room (or if it is outside, as a courtyard). Arrange it so that the stair and the room are one, with the stair coming down around one or two walls of the room. Flare out the bottom of the stair with open windows or balustrades and with wide steps so that the people coming down the stair become a part of the action in the room while they are on the stair, and so that people below will naturally use the stair for seats.
  • In our house: We partially implemented this pattern. We placed our staircase in a central location, and we made sure that it was a space in its own right, with nice wide landings (which we plan to develop into window seats). However, a semi-translucent wall, and the way that the stairs protrude from the building keep the staircase from being fully integrated with the main living areas. A person coming down the stairs may be part of the action in the dining room, but they are almost completely cut off from the living room (although there is a "spy hole" that allows limited interaction).
Stair Seats (125)
  • Problem: Wherever there is action in a place, the spots which are most inviting, are those high enough to give people a vantage point, and low enough to put them inaction.
  • Therefore: In any public place where people loiter, add a few steps at the edge where stairs come down or where there is a change of level. Make these raised areas immediately accessible from below, so that people may congregate and sit to watch the goings-on.
  • In our house: Our stairs are not actually good stair seats. They are fairly wide, but not wide enough that they can be used for getting upstairs and sitting on at the same time. They are fairly deep, but not deep enough for most people to comfortably sit sideways on. A structural column keeps them from protruding into the room, so they don't provide a good vantage point. Thus, it speaks to the power of this pattern that even though our stairs were not designed as effective seats, they are still used as seats when we have large crowds over.
Staircase Volume (195)
  • Problem: We are putting this pattern in the language because our experiments have shown that lay people often make mistakes about the volume which a staircase needs, and therefore make their plans unbuildable.
  • Therefore: Make a two story volume to contain the stairs. It may be straight, L-shaped, U-shaped, or C-shaped. The stair may be 2 feet wide (for a very steep stair) or 5 feet wide (for a generous shallow stair). But, in all cases, the entire stairwell must form one complete structural bay, two stories high.
  • In our home: Since we were working with a team of an experienced builder and architect, we were not in danger of doing anything terrible here. However, we did find that our initial estimates of square footage always forgot to account for the stairs, and the stair area on the floorplan always felt larger than they needed to be. There is, indeed, something about the three dimensional volume of a staircase that makes it hard to grasp intuitively.

Inspiration

Shortly after purchasing our property, we started to collect inspiration pictures (alas, this was before Pinterest, so our inspiration pictures were managed by a Google doc). Without trying, a number of themes emerged, and we worked them into our final stair case.

Although the most stunning stairs were the ones with little to no visible support of the treads, when it came to visible supports, a number of our inspiration pictures had dark supports with light treads. Others had light supports with dark treads. The contrast and rhythm provided by contrasting treads and supports would become a central theme.




One thing you may notice if you spend a lot of time on architecture blogs looking at modern houses is that they generally have impractical rails and balusters. These homes are clearly somewhere with less stringent building codes than Bellevue, WA. Fortunately, we were able to find some inspiration images that met the requirements imposed on us by the city and our desire not to have people fall through the stairs.


The vision which inspired us, even before we started thinking about the practical constraints, was long bars which spanned multiple levels of stairs. We liked how having a single bar span multiple levels tied the levels together to make the staircase a single sculptural piece.



We had other inspirations, but these were the features that stuck as we turned this into something real.

Actuality

There are a lot of practical constraints that go into stairs. Local codes constrain most of the distances between elements, available materials constrain what is cost effective to use, practicality of assembly constrains how elements can be put together. These practical constraints had as much influence on the final form of our stairs as our inspirations.


To complement the material choices throughout the rest of the house, we chose to contrast wood and metal. The railings, balusters, and supports are all blackened steel. Steel is also used for the bars between treads, which ensure that nothing too large, such as children, can fall through.


The treads are a 1" oak slabs, each made out of smaller pieces of oak, bonded to a dark stained piece of plywood. We ended up really liking the rhythmic effect of the alternating light and dark lines, but this was almost accidental. Brent, the onsite manager for the first part of construction, found some nice, relatively cheap, solid white oak treads at Home Depot. These needed to be made thicker to support the necessary span, so each tread was reinforced with a piece of high quality plywood. The plywood is set back and darkened to give a stronger appearance of floating to the lighter oak.


Codes and assembly also influenced the tread design. Because of the constraints on tread overlap, each oak tread had to be lengthened by about two inches. After that, each tread had to be precisely sized to work with the balusters. Overall, the additional labor balanced initial low expense of the materials, but the result is visually more interesting than solid slabs, and it is unique among the staircases we have seen.


Another practical difficulty was figuring out how to assemble the balusters, rails, and treads. The balusters are 16 foot steel rods which span three half-flights of stairs. By code, The maximum distance between balusters is 4.5", and they need to be attached to the stairs for structural stability. Because of the differences in floor-to-ceiling height between the main and lower floor, the number of treads per half-flight varied, making alignment of the balusters difficult. To make assembling this puzzle easier, Yuval and Brent decided to attach the balusters to the stairs using stainless steel standoffs. These standoffs screwed into the sides of the treads, which was easier, more stable, and risked less damage than drilling through the treads. The standoffs provide a nice contrasting visual element. Getting the standoffs in the right location was a puzzle that took Dave, who was leading the effort, several days. He had to mark each standoff location with masking tape, use a laser sight to figure out where the corresponding standoffs would go on the lower levels, mark those, and then move on to the next one. Occasionally, the max 4.5" distance between the steel rods would mean that a standoff would have to go in a position that could not be securely attached to a tread. At that point, that standoff would be adjusted, which led to all the other standoffs that had been placed so far needing adjustment. The precision paid off, and after getting everything marked up, they were able to install the standoffs and slide in the rods pretty quickly.

Overall, we are quite pleased with how the stairs turned out. The use of white oak and steel integrates them with the rest of the house, while the tread and baluster design adds a unique, sculptural touch.