Tuesday, February 23, 2010

Renovation Of Commercial Buildings Requires Creativity And Endurance.

The renovation of commercial buildings requires creativity and endurance by the owner and architect. The building was doomed by engineering reports.

Defining the Project
The identity of the decision makers and the documentation of the original design and construction of the building were lost years ago. Stimulus money was poured into Texas communities during the WPA (Works Progress Administration) in an attempt to boost the economy and provide work during a failed economic time. A small community building was constructed in Irving, Texas in 1936 during this era. The building continued in use for many years but slipped into use as a dilapidated storage building until 2000 when the owner hired the firm of Larsen Dye Associates Architects (LDaa) to conduct a study to evaluate the previous engineering and architectural studies that had doomed the building to destruction.

The owner was sensitive to sustainability before most people recognized that adaptive reuse of buildings will leave a smaller carbon footprint on the environment than new construction. At the turn of the millennium most people viewed renovating buildings as being attentive to historical preservation or just maintaining a piece of history. The sixty four year old building had defects and it had been neglected and abused over the life of the occupancy. Before the renovation project was undertaken, the owner contracted with LDaa to provide an investigative study to identify the construction background of the building, structural deficiencies, code issues, and a probable cost to allow the building to be occupied.

The building was a large open space with a kitchen and toilets on one end. There were three renovations and additions to the main building. The first renovation (phase 2) added capacity to the open meeting area, which was later divided to office space. The second addition (phase 3) provided toilets with the exterior constructed of wood siding and brick. An adjacent building owner constructed a parking lot that modified the grading of the building, placing the toilet addition below finish grade. In the third renovation (phase 4), a new air-conditioning system was installed requiring an upgrade to the electrical. In this renovation, the plaster covered walls were covered with inexpensive paneling, the kitchen was updated and a lay-in ceiling was installed covering the original wood ceiling. Partition walls were added to subdivide the space for storage after the building was no longer occupied.

The original modified scissor trusses were not engineered to direct the loads vertically onto the exterior bearing walls. The force exerted by the trusses caused the double wythe exterior walls to deflect outward by as much as four inches in some locations. The phase 2 addition to the open space was constructed with tilted exterior walls to match alignment with the existing leaning walls. Additional horizontal wood beams were added in an attempt to stabilize the outward movement of the walls. In the final construction of phase 4, the vaulted ceiling was filled in with suspended air conditioning ducts and an insulated lay-in ceiling. The roof was not designed to withstand the horizontal thrust of the additional weight of the duct work and new ceiling. The roof trusses moved horizontally across the top of the brick walls and the horizontal beams added in phase 2 sheared their connections. The sagging roof created more failures as water infiltrated causing wood to rot and attract termites. The phase 4 renovation allowed damage to continue unnoticed as wood rotted and metal rusted and corroded. Each phase of construction had a different foundation slab. The shallow slabs moved independently and at different rates. Each slab was at a different finish level. The structural exterior walls were constructed of three different colors and size of bricks. The walls had cracks and openings at the construction joints.

Plumbing and Mechanical
The plumbing failed as the slabs moved under the highly expansive soils. The water, sewer and gas lines were rusted, corroded and leaked. The suspended mechanical ductwork connections failed as the roof sagged. The heating and air-conditioning system had deteriorated and replacement parts were not available.

The electrical system was out of compliance and under capacity. The electrical service power was disconnected due to multiple water leaks in the building that had rusted many of the conduits, panels and electrical fixtures. The demolition crew uncovered a few historical lighting fixtures but none that could be salvaged. The building did not contain telephone or internet connections.

The exterior walls tilted outward and needed to be structurally secured. All of the doors and windows were damaged beyond reuse. The building was not accessible even though a ramp had been added to the front entrance and some misplaced grab bars added in the toilets. The interior plaster covering the brick walls contained asbestos. The interior partitions were damaged by termites or rotted due to water infiltration. The ceilings had collapsed dumping the insulation and ceiling tiles on the floor. The vinyl asbestos tile (VAT) flooring had peeled up due to moisture under the slab. The kitchen cabinets and equipment was damaged beyond repair. The interior and exterior walls of the toilet addition had crumbled after being exposed to water for extended periods of time.

Decision to Renovate
Instead of demolishing the building, the owner decided to remove the unsafe and highly deteriorated portions of the building and replace them in a manner to complement the original architectural character of the building. The building had no historical landmark designation because it had been renovated without consideration of preserving or being consistent with the original WPA design. This allowed the owner to attain grant funding for renovating a public use building without having to follow guidelines for preservation.

Programming and Design
The program from the owner provided the limitations that would define the final design. The character of the building should replicate as close as possible the design features of the original building as shown in a photo archived in a newspaper article. The footprint of the building should not exceed the current perimeter except as required to meet accessibility requirements. The owner would abate the hazardous materials after the building interiors were removed and the structure stabilized.

The rear or west exterior wall and the phase 3 addition of the toilets were deteriorated to the point that they could not be reused or stabilized structurally. The roof trusses and interior partitions were removed as the abatement proceeded. The interior and exterior doors and windows were removed along with all millwork and paneling. The building was then encapsulated and the (VAT) flooring and plaster coverings were abated.

After evaluating the site, LDaa's design team provided recommendations for stabilizing the floor slabs and reducing movement of the walls. The adjacent parking lot construction channeled water into the site causing the area drain to exceed the capacity to handle the runoff. The owner had covered the area drain causing water to pond around the building. The team designed a concrete border around three sides of the building to direct runoff to the larger area drain and to the street storm sewer. A large damaged tree was removed to reduce future damage to the slab and provide clearance for drainage.

Structural Slabs
The renovation design called for reusing the existing slabs after removing a four foot wide section and doweling the slab sections together. The final slab was to be floated with an epoxy structural topping to level the finish floor. After removing the four foot wide section, the exposed slab illustrated that the slabs had been built with out steel. To complicate the reuse of the slabs there was a void under the slabs where the soil had expanded and contracted seasonally forcing the supporting soils clear of the slab. The owner approved redesign and removal of the remaining slabs leaving the perimeter beams in place. The new monolithic slab was designed to connect the perimeter beams to provide additional support of the walls. To permanently stabilize the exterior walls, an interior box diaphragm was constructed of structural steel studs. The box provided positive connections to the brick walls through auger type bolts to resist withdrawal. The new structural studs provided the top bearing plate for the new roof trusses releasing pressure on the exterior walls. Control joints were incorporated in the interior gypsum board to allow movement to minimize cracking of the walls and ceilings.

Architectural Exterior Details
LDaa selected a roof shingle that matched the diamond pattern of the roof shingles in the owner's archive photograph. The shingles selected were a coastal high wind resistive profile that will extend the life of the roof. The original windows were steel casement but had been replaced by single pane extruded aluminum frame windows. To match the original window profile LDaa selected energy efficient vinyl covered wood windows. An insulated steel door was designed to match the frame of the original door and to provide security and durability. Any exterior brick that was removed was salvaged, cleaned and reused. Additional brick to match the shape and texture were purchased to complete the construction. This resulted in four colors of brick and three colors of mortar. The architect selected a special coating material for the brick that could be spray applied. A single color for the brick was selected from samples applied on site. All of the exterior walls were coated with the water resistant stain including the mortar joints. A mortar color was selected from the stain samples and the joints were hand painted. A ramp was constructed from the north parking lot to the entrance and was concealed by a lighted screening wall that also served to mount the building signage.

Interior Finishes
The color palette was set by the existing brick chimney that would be exposed in the open space of the entry. A durable modular carpet was used as floor covering. A pattern of coordinated stripes was added to cover any movement anticipated in the slab. A floor base color was selected to match the brick and carpet. The walls and ceilings were painted a neutral color. The tile patterns in the toilets were designed to mimic patterns indicative of the era of the original building. A red mahogany finish was selected for the solid wood doors to match the floor and base.

The building had open space and a clear span roof. The infill of office and workrooms was accommodated into the floor plan to provide accessibility. One of the first design decisions was to demolish the toilet addition that consisted of a space too small to accommodate new toilets. Designing accessible toilets was simpler after we set the floor plan for the new toilet area. A conventional slab was used along with exterior walls of metal studs and brick veneer. The kitchen area was large enough to construct an accessible layout. The main entrance was too narrow to meet the clearances for a person in a wheelchair to open the door. Automatic electronic door openers were added allow a wheelchair to enter without having to touch the door. Security features were added to the openers to lock down the facility and prevent entry by an unauthorized person. On the site, bridges were added over the water flumes. A ramp was added from the parking area to the main entrance and exit.

Lessons Learned

  • The construction cost to renovate was slightly less than new construction.

  • The owner was able to have a larger building floor plan by renovation than by new construction. New construction would have required compliance with current parking, landscaping, and setback requirements.

  • The special coatings on the building provided a unified color and the material sealed the old brick from moisture that could create additional deterioration. If the owner had chosen, they could have sealed/colored each brick to resemble a blended pattern.

  • Do not plant trees closer than ten feet of a building.

  • Maintain positive drainage around the slab of a building.

  • Avoiding interior load bearing partitions allows a flexible floor plan for adaptive reuse.

  • Use color to highlight the existing patterns of building materials.

  • Allow building materials to extend inside and outside to tie the building together.

  • Install the most energy efficient equipment you can afford at the time of construction to extend the life cycle of the building.

Project Superintendent: Eddie Black