Temporary protection for historic stairways

Case Study

Protecting Historic Stairways during Rehabilitation
The Villard Houses
Location	New York, New York
Owner	National Park Service
Built	1880s
Project data
Project date	1977-1980
Affected materials	stair materials (variety of woods or marble)
Treatments	using plywood and padding to cover walls, steps, and balustrades during restoration
Products used	plywood, padding, screws, fiber board, wooden stops
Project team
Architect	Emery Roth and Sons, P.C

The original residences known as the Villard Houses were designed by the firm of McKim, Mead and White and constructed in the 1880s in the style of a Neo-Italian Renaissance palazzo. The interiors of the buildings contain a remarkably high quality of design and workmanship with extensive use of decorative paintings, mosaics, paneling and marble. The elegant interior staircases which contribute to the richness of the interior spaces were constructed in a variety of designs and materials (see figure 1). In the late 1970s the Villard Houses were adapted to serve as function rooms for an adjacent hotel while portions were retained for use as existing offices. As part of the project, a system was designed for fitting the staircases with temporary protective coverings to avoid damage while still allowing for their use in the course of the extensive renovation work

The Villard Houses include stair- ways ranging from very elegant (seen here) to quite sample. All could have been damaged if not protected during the extensive rehabilitation work.

Problem

Historic staircases were rarely designed to take the abuse which occurs during major renovation work. Even when trash chutes and material hoists are located through windows, staircases are still subjected to dirt and heavy wear during construction work, and the risk remains of incurring costly or irreparable damage. Stairwall materials such as marble, wood wainscoting and Lincrusta wall covering, as well as balustrades and stair treads, are particularly vulnerable to damage. Where there are tight turns and narrow staircases, the risks of damage are even greater. Closing off the stairs usually is not practical either because the stairs are needed for daily use during construction or must be kept open for job safety. In most instances, the best preservation approach and the one that often proves economical in the long run is to provide sound and effective protection of the staircase in situ. The project architect should be the one to design a protection system for the staircase.In designing the protective system, care should be taken to protect the walls, the balustrade, and the staircase itself. With the Villard Houses, a simple, practical and effective system was developed to protect the staircases during the renovation work. The wide range of staircase designs, decoration, and finish work found in the Villard Houses furnished ample opportunity to test the broad applicability of this protective system. It is described in the following sections, with some liberty taken in making minor refinements for the benefit of others wishing to use it. Significant interior features in historic buildings should be protected during construction work.

Solution

The basic system consisted of using plywood and padding to cover the walls, steps and balustrade without using any anchoring devices that would damage historic material (see figure 2). Screws were used rather than nails in fastening the wooden temporary pieces together to lessen the chances of accidental damage to historic fabric and to facilitate disassembly.

Figure 2. A system for protecting the decorative staircases was drawn and specified by the project architect.

Stairsteps

The plywood treads extended past the nosing on the historic steps with soft fiberboard set in place beforehand as additional protection.

Both the marble and the wooden stairsteps were identified in the planning stage as being vulnerable to damage and excessive wear during the renovation work. The decision was made to lay a temporary wooden covering over the existing stairs in a manner which would provide for maximum protection of the historic fabric without hindering daily use of the stairs by the construction crew (see figure 3). A sheet of soft fiberboard served as a cushion between the wooden covering and the historic stairsteps. The floorboards extended approximately one inch past the existing treads to provide better protection for the delicate nosing. For each step, a second piece of fiberboard was cut to rest against the riser, The temporary wooden treads applied over the fiberboard were cut out of plywood rather than planking, since plywood has a greater resistance to cracking and curling in such wide widths. For the risers, less expensive planking sufficed. In both cases, fire retardant wood was specified. In assembling the temporary steps, power-driven screws of specified length were used. Screws rather than nails were chosen in order to avoid pounding damage to the masonry joints and the relatively thin historic marble panels used in the staircase construction, and also to reduce the chances of damage during disassembly. Wooden stops measuring one inch square were first screwed onto the end of the plywood treads; the plywood set onto and against the two fiberboards used on each step; and then the planking used for the risers was set in and secured in place with screws. For disassembly, the process was reversed.

Balustrade

Once the temporary wood floors were installed, the balustrades were encased in plywood (see figure 4). For the sections running on top of the handrail, 5/8 or 3/4 plywood was used, cut wider than the handrail to permit attachment of 2 by 4 blocking on the underside for securing the 1/2 plywood side walls away from the balustrade (see figure 5). For padding, neoprene was glued to the face of the blocking closest to the edge of the handrail as a cushion in case the covering was jarred. The handrail was cushioned further by soft fiberboard glued to the underside of the plywood top. After the top section was assembled, the side plywood walls were cut and attached; the side walls were additionally blocked out wherever the newel posts protruded beyond the balustrade (figure 6). The entire assemblage was secured tightly with judicious use of braces and blocking or where necessary was screwed to the temporary wood floor.

Figure 4. (left) This cross-section of one of the staircases shows that the entire historic balustrade was temporarily encased in wood during the renovation work. Figure 5. (right) As with the step detailing, the temporary protection over the balustrade and hand railing used plywood padding, blocking, and strew fasteners to minimize possible damage.

The balustrade on the left side of the photograph has been entirely encased in plywood to protect it from damage. Note that the kick-out at the end is due to the protrusion of the newel post.

Stairwells

A temporary eight foot high wall was constructed to protect the historic wood paneling, marble and decorative trim typically found along the stairs. The wall covering consisted of plywood attached to a wood frame that had been designed so as to require no anchor attachments to the historic wails (see figure 7). The triangular shaped sections of the frame which supported the plywood rested on the plywood floor covering. Wherever the frame abutted historic material, a thin neoprene pad was glued to the wood beforehand to avoid scratching. For greater rigidity, 2 by 4 sleepers were added in various locations to connect the triangular sections of the frame. In cases where the historic handrail protruded considerably and was not temporarily removed during construction, the triangular sections were not pre-assembled, but rather constructed in place around the railing.

Evaluation

The cost of this work was quite modest and the protective system was sufficiently flexible to be adapted to staircases of different dimensions, designs and material. It was easy to construct and required only common fasteners and materials. Most importantly, this system effectively protected the staircases against damage during the renovation work (see figure 8).

Project Cost

The cost of the overall rehabilitation work was approximately $10,000,000; cost for the temporary stair covering was too small to be broken out in the construction cost.

Gallery

Figure 7. The temporary wall covering going up the stairs consisted of plywood mounted on a wooden frame. Neoprene padding was used where the fame abutted the historic walls. The method shown here requires no fasteners to be used, avoiding possible damage to the decorative walls.   The entire historic staircase has been protected against possible damage during the renovation work. The balustrade on the left has been encased in plywood; the floors have been covered; and a temporary plywood wall constructed, shown on the right and at the landing. Note that the plywood wraps around the wall at the entranceway.

Original source: http://www.nps.gov/tps/how-to-preserve/tech-notes/Tech-Notes-Protection01.pdf This article contains material based on a work of a National Park Service employee, created during the course of the person's official duties. As a work of the U.S. federal government, such material is in the public domain. See the NPS copyright policy for more information.