Stair Logistics
Eligible Staircases
After walking and measuring more than hundred staircases here in Pittsburgh, it is clear that Pittsburgh staircases fall into two broad design categories. One category of stairs are those that are cast in place, complete with vertical risers. These cast stairs will not be suitable for this project. The other category of stairs are those that are constructed of cast plank stair treads and are assembled on cast supports. This assembly process allows vertical riser gaps between the stairs of three and five-and-half inches. It is these gaps in the public stairs that the proposed stair inserts are designed to fill. Because of the variety of stair heights, individual measurements will need to be taken for each staircase that these risers are to be cast for.
Materials Handling
The weight of each stair riser will be between forty-three and sixty two pounds, depending on the gap between the stairs, most at the lower end of this spectrum. After casting, stairs will be brought on-site in groups of ten and individually carried up or down the staircases to their numbered positions. Records of the individual stair locations, dimensions, and ornamentation will be kept and publicly recorded in the event that any stair riser is damaged and needs to be replaced.
Installation
The stair inserts are designed so that they will stay in place entirely by their own weight, however, they should also be fixed in place to avoid them being removed. The stair inserts will be tipped into the gaps between the stairs and either mortared or glued into place. The inserts are designed so that a wedge of mortar can be used to fill the triangular space below the support tabs to prevent the riser from being tipped forward and being removed. Mortaring the stair risers in this way is not the preferred installation method, as having this mortar in place will complicate stair tread replacement. A better installation method will be to use a concrete adhesive between the tabs of the riser and the structural supports of the stairs. If this adhesive is used, temporary spacers will be placed between the stair tread and the stair riser to assure sufficient clearance for stair replacement without the need for the riser removal.
