Project Profile: Mt. Vernon Monument Restoration by Ruff Roofers

NEW PROJECT PROFILE:

Mt. Vernon Monument Restoration by Ruff Roofers

On the eve of its Bicentennial celebration, the Mount Vernon Washington Monument has been undergoing a large-scale restoration to prepare for its third century as a centerpiece in downtown Baltimore. Although the monument is in structurally sound condition, water infiltration over the years has led to masonry deterioration as well as damage to contents housed in the museum area. Ruff Roofers, Inc. was contracted to install a new liquid-applied roof system on the lower terrace of the monument, which also serves as the roof of the museum space.

The initial phase in our scope of work, namely demolition of the existing roof system, quickly became our first challenge. The design intent was to revert back to the original layout of the roof, which consisted of nearly 3-ft wide marble slabs stepping down to the outer parapet with through-wall scuppers providing drainage. Over time, however, layer upon layer of roofing membranes, insulation, and poured concrete had been built up on top of the marble, forming a level surface. This meant that our demolition consisted of removing the concrete and other roofing materials, which ranged in thickness from 4 to 16 inches, down to the marble substrate. Because of the equipment needed to remove the concrete, great care had to be taken not to damage the marble.

Once the marble was exposed and repairs were made to any large cracks or divots, we began installation of the new Siplast Parapro roof system. The first step was to install a torch-grade modified bitumen base sheet directly to the marble substrate. Knowing that the seams of the base sheet would telegraph through the subsequently installed liquid-applied system, and also anticipating a significant amount of visitors observing the terrace area, we wanted to make sure that this first layer was visually pleasing. Our superintendent and foreman worked together to lay out the sheets prior to installation so that the seams would end up being minimal and symmetrical.

Next, we installed the remainder of the Parapro system, consisting of multiple layers of coating with reinforcing mesh and quartz surfacing. Our sheet metal craftsmen field-fabricated through-wall scupper sleeves and splash pans from lead coated copper, and these were flashed in accordingly. Fabricating these in our shop would have been ideal, however the varying sizes of all eight scupper openings made field fabrication, although more time consuming, a more prudent route to ensure that the sleeves and pans fit perfectly. After installing the Parapro flashing up the parapet and interior plinth walls, new lead coated copper counter flashing was set in newly grinded reglets and sealed.

The final item of our scope was the refurbishment of four historic skylights, which, due to their age and maintenance over time, presented a few challenges. The overall challenge was to provide the best product to the owner while minimizing any changes to the skylights’ appearances. Because of the thickness of the new roof system, the bases of the skylights were now too small to properly fit onto their curbs. The skylight “crowns” needed attention as well, as these were in poor condition. We came up with our recommendations for both issues as well as a few alternatives for the designers, which allowed them to weigh best waterproofing practices against historical integrity. In the end, we were able to replace merely the glass, the top “crown” area, the battons, and the counter flashing at the base without noticeably changing the appearance of the skylight and still providing the owner with a finished product with which we are confident will not leak or fail for many years.

We are honored to have been a part of the restoration of the country’s first Washington Monument, and we are proud of the work that we have performed. Although several challenges were faced on this project, we were able to overcome them to successfully complete the job and become a small slice of the monument’s illustrious history—and surely steadfast future.