West End Lofts | Denver, Colorado
Issues: Water leakage, construction deficiencies, isolation joints, moisture and noise.
Situated on Wazee Street just steps from the Platte River, West End Lofts sit above this busy Denver street. Wazee is located in lower downtown, where many of the buildings are historic, like West End. West End Lofts’ balconies allow homeowners to enjoy fresh air and views of the mountains and the Denver skyline in a completely urban environment. But this luxury living was not always so pleasant; sometime before 2005, homeowners noticed water was leaking into their units through the windows, doors and walls adjacent to their balconies. The water would wet their interior wood floors, resulting in cupping and buckling of hardwood floors and causing damage to the drywall. One unit floor was replaced twice due to resultant damage from this water intrusion. A number of construction deficiencies were responsible for the damage: there were no waterproofed isolation joints, no drip flashings, and the historic systems were not well waterproofed or integrated with the surrounding modern moisture-management materials.
There were numerous problems with the façade, some of which were directly related to the complexity of converting a historic building to a modern residence. The lower portion of the building relied on the exterior of the original structure to provide waterproofing, including the historic salmon brick interior walls that was newly exposed to the elements during the remodel. The salmon brick was never intended to be exposed to the exterior and this original brick was not integrated with the new or even the existing openings. As a result, these openings were not air or watertight. The upper floors were new construction and were not properly integrated with or properly designed to drain over the historic portions.
One specific defect in the integration between the new and the old materials involved the sealant, or isolation joints, in the residence. When the different materials expand or contract because of thermal differences—the metal of the windows, the stucco around the windows—gaps were created between the adjacent materials, allowing water to get into the building’s interior and into the substrate below. This is typically prevented by isolation joints comprised of shaped sealant and a backing material. No isolation joints were constructed between dissimilar materials, so windows and doors leaked through gaps created by differential thermal expansion. Homeowners noticed the effects of these open joints first: staining on the walls, swelling of trim, and biological growth. No consideration was given to design or construction of the interfaces.
The façades are the first layer of protection for the interior of any building against moisture and air intrusion. At West End, the new skin of the building envelope was not constructed properly. Weather-resistive barriers were not properly installed or integrated with other moisture-management components behind the stucco and masonry façades, and penetrations in the roof were left unsealed or installed in a way that they trapped water instead of allowing it to flow past. The CMU was not treated with exterior products, and therefore could not be integrated into the system.
The balconies that offered such beautiful views to the homeowners were prone to pooling water because they were not sufficiently sloped to drain water to the exterior. Instead, they were sloped back towards their unit, directing water against the façades, doors, and into units. Not only was this an issue with water entry, this poor sloping trapped water that froze on the balcony surfaces, creating a slip-fall concern.
At some of these balconies, the deck membrane was not integrated correctly with the exterior façade. Because this membrane was on the surface of the deck, and these decks were not sloped to drain the water away from the building, water leaked into the building, into the units below, and into the office space on the first floor.
In the parking garage, mortar from the original salmon brick construction began to crumble, leaving voids in the façade. The deterioration became so bad that areas had to be fenced off as a safety measure by the original contractor, who obviously recognized this as an issue. Failing to properly seal the parking garage from moisture above lead to leaks into the storage areas, damaging not only the building itself, but also personal property.
Noise, noise, noise
Another concern for the occupants was the sound transmission that occurred between walls and floors. Residents could hear their neighbors quite clearly through walls on the same floor, or from impact noise from the floor above. The construction of the West End Lofts did not meet the code minimum standards, much less meet the expectations of what was marketed as a luxurious living environment in downtown.
Contributing to the noise complaints was street noises coming through the single-pane historic glazing that was used. But sound wasn’t the only thing coming through; the windows were unable to provide weather resistance, permitting moisture and air intrusion. In the original construction, this warehouse building had limited interior water-sensitive finishes; the poor window performance had no impact on the historic warehouse space. When insulation, drywall, finishes and flooring were added to the units, however, the modern materials became water damaged.
The litigation investigation
As part of the litigation investigation, SBSA’s staff conducted a variety of testing to determine the performance of the construction and the installation. Intrusive testing was conducted to determine how the façades were constructed and integrated. In conjunction with contractors, the façades were cut away to reveal the underlying components. Window spray tests were conducted in accordance with ASTM standards to determine the performance of the windows and doors. Using this test method, SBSA’s staff was able to isolate the locations of leaks. Blower door testing was conducted on windows and doors to test the thermal efficiency, and sound tests were conducted using tapping machines to determine the field test results of the sound isolation.
As part of the trial, members of SBSA’s staff were examined, including some who’d never provided courtroom expert witness testimony prior to this case. Following trial, the West End Lofts Homeowners Association was awarded $4 million. Following payment of fees, reimbursement of emergency repair costs, and a set-aside for long-term maintenance of the building, these funds were used to address the multitude of construction deficiencies on this site.
After receiving their settlement, the West End Lofts HOA hired SBSA and a local reconstruction contractor to repair their property. The stucco and brick façades were repaired and the moisture-management materials were incorporated correctly with each other. The balconies were re-sloped so they drained toward the exterior of the building, and the membranes were installed and properly integrated with the exterior of the walls and fenestrations.
Because of the historic nature of the building and the neighborhood, replacing the windows was not a simple task. It was important to the city of Denver to maintain the historic façade, and simply replacing the single pane windows with double-pane windows was not immediately an option. Instead, a professional glazer, recommended by the Historical Society, was hired to re-glaze the window. After three failed attempts, an appeal for a variance was undertaken. Representatives from SBSA, the contractor, and the HOA appealed to the Lower Downtown Design Review Board for approval for new windows.
The contractor proposed using double-pane windows that were similar in look to the large, steel, single-pane historic assemblies that were part of the original building. After presenting to Lower Downtown Design Review Board, the double-paned windows were approved and installed. The double-paned windows offered better thermal performance and better sound isolation, reducing the amount of street noise.
One of the largest challenges for the HOA, however, was whether to make the sound repairs. Fixing sound transmission problems in an existing building can range from inexpensive, easy alterations to costly and difficult reconstruction, depending on the cause of the transmission problems. At West End Lofts, part of the cause of the poor sound isolation was the floor and wall construction between the units. In order to make complete sound repairs, it would have been necessary to tear down the interior walls, re-frame correctly using sound isolation construction including resilient channels, and then rebuild the interior walls. For some of the owners, this extensive process was not appealing due to the intrusive nature of the repairs, and the impact on personal, custom finishes above and beyond the HOA property. Without a guarantee the HOA would pay for the costs to replace these custom interior finishes, homeowners were reluctant to have their walls torn down. The HOA faced the question: attempt to make costly sound repairs, unsure how effective the repairs would be? or Use that money instead for other repairs or as part of a reserve fund? The HOA chose to make certain sound repairs that were deemed to be of value because they were effective, and reduced noise complaints.
In the summer of 2009, the West End Lofts repair project wrapped up. Owners now have an exterior façade capable of managing the expected moisture, an increased level of sound performance, decks that can drain water, windows that can effectively shed moisture and air, and the overall building that they should have had from the inception of the construction years earlier.