Leaks, Drafts, Vacancy Siphon Profits: Wall Facelift Repositions Aging Office Building
By Bill Gladu
Owners of a three-storey 100,000-square-foot multi-tenant commercial office building were following what they believed to be a good strategy - namely having the leaks repaired from the exterior on an as-needed basis. The problem was that the low-cost repairs did not seem to be working.
On rainy days, water leaks through the exterior walls were causing absenteeism within the tenants' suites because workstations close to the perimeter walls would flood with water that penetrated the building skin. Drafts through the envelope were compounding tenant discomfort on cold windy days.
Contractors were called on to repair and repaint drywall and clean carpets after water damage, while in-house maintenance staff was distracted with emergency clean-ups and working overtime to get things back to normal, letting some regular duties slip. Exterior and interior repairs were adding to the overall operating costs and cutting into the bottom line profitability of the building.
The vacancy rate in the building was rising and new tenants were not coming in. When prospective tenants toured the building on a rainy day, they'd get to see the full effects of the ongoing water penetration issues and, understandably, show little interest in leasing. Even on a sunny day, the tired exterior appearance of the building contributed little to curb appeal.
Although the owners were hesitant to spend a significant amount of money, they came to the realization that the conditions had reached the point where things would only get worse if they didn't try a new strategy.
Originally constructed more than 30 years ago, the structural steel building had an exterior cladding system comprised of double-glazed aluminum strip windows and wood stud walls. The wood studs were filled with R12 (RSI 2.11) batt insulation, sheathed with plywood and protected from the exterior rainwater with a system of asphalt impregnated building paper and clad by painted vertical cedar siding. The roofline was capped with a large soffit.
Engineering assessment and investigation indicated that existing building paper and siding was no longer keeping out moisture. The retrofit approach was to remove the existing cedar siding and building paper, while leaving the remaining wall assembly in place.
The new cladding assembly included a self-adhered membrane that acted as the new moisture barrier, additional R21 of insulation, and a new composite aluminum panel cladding. After accommodating for thermal breaks in the insulation and the thermal resistance of the windows and roof areas, the new insulation was modeled to improve the effective thermal resistance of the building by more than 20%. At the windows, a new head flashing detail was installed.
Tenants could continue to occupy the space and carry on their daily activities with little disruption from the construction, which was occurring on the exterior of the building. Constant communication among the contractor, building owner and engineering consultant - discussing issues such as location of material storage, where and when the work was to be undertaken, and other issues that affected the tenants use of the property and parking - ensured that tenants' needs were addressed in a timely manner throughout the work.
The contractor was charged with keeping the owner and consultant up to date with the progress and any changes that occurred. With this information, the tenants could be quickly notified of any schedule change.
The timing of the project posed another significant challenge. Due to various factors, the work was undertaken from the late fall through the winter and into the very early spring. Cold and inclement weather particularly heightened the importance of as short a period as possible when the building was temporarily exposed to weather - after the exterior cladding was removed - to when the building was enclosed with the new membrane.
RENEWED COMFORT & IMAGE
The owner now reports vastly improved tenant satisfaction with no evidence of leaks or uncomfortable drafts. The increased thermal resistance of the new cladding system and improved air barrier have reduced the building's energy consumption and maintenance costs have been brought down to industry standard levels.
The new appearance makes the property attractive again to tenants and the marketplace. Shortly after the work was completed, the building achieved full occupancy and its market value increased well beyond the cost of the repair program.
Bill Gladu, P.Eng., MBA, LEED AP is a Principal in the Building Science and Restoration Group with Read Jones Christoffersen's Toronto office. The national consulting engineering firm was the engineering consultant for the above project. For more information, see the web site at www.rjc.ca.