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Introduction
There are four major reasons for curtain wall renovations:
1. To eliminate the curtain wall problems caused by water leakage such as sick air building, loss of insulation value, interior water damage, and corrosion of mullion anchors.
2. To correct the structural problem discovered in service condition such as glass breakage due to stresses induced by temperature change and/or story drift (e.g. John Hancock Building in Boston and CNA Tower in Chicago).
3. To renew or change the existing exterior aesthetic feature.
4. To upgrade certain curtain wall functions or to revitalize certain degraded curtain wall functions such as thermal or sound insulation value.
Most renovation projects are compelled by Reasons 1 or 2 above. Usually, once the decision to renovate has been made, Reasons 3 & 4 become options for consideration.
There are two major logistical means for handling renovation projects. The first is to maintain the building functions by minimizing the disturbances during the renovation work. The second is to vacate the building during the renovation work. In addition to the unique long-term functional performances provided by TingWall?after renovation, TingWall?solves many difficulties of using a conventional system encountered during renovation as explained below.
Conventional System Vs. TingWall™ renovation
with building occupied and functioning
1. With a conventional system (either Unitized or Stick), the renovation work includes the following steps.
Step 1 : Taking down the existing wall panels.
Step 2 : Taking down the existing horizontal supporting
frames.
Step 3 : Taking down the existing mullions and
mullion anchors.
Step 4 : Installing new mullion anchors. A major
problem is encountered due to the difficulty of installing the anchors on the
cured concrete slab and many field tests must be performed to ensure the
consistency in the strength of the installed anchors. This is a costly
step.
Step 5 : Installing new supporting frames.
Step 6 : Installing new wall panels. Two major problems are encountered in this step. The first problem is the lack of erection flexibility, or the inability to skip one area and back-fill later since erection must be sequential. For minimizing the interruption of the interior operation, it may be desirable to skip and back-fill certain areas. The second problem is due to the fact that the new wall panels are not compatible with the old frames, thus, the wall panels for the last bay between the new and the old frames can not be installed. This is known as Building Hole Problem. Protecting the Building Hole against severe weather and vandalism is a very costly and difficult task. Consequently, many renovation projects were forced to vacate the building.
2. With TingWall™, the following three options
are available.
Option 1 : If the existing mullions and anchors are structurally sound, the existing mullions can be easily converted to TingWall™ mullions by using custom-designed adapters to be secured to the existing mullion of any shape. This eliminates the most costly Steps 3 to 5 in the renovation using a conventional system. In addition, due to the non-directional erection feature of TingWall™ the two major problems of Step 6 in the renovation using a conventional system are eliminated. If this Option can be used, the cost of renovation using TingWall™ would become a fraction of the cost of renovation using a conventional system. The most notable successful and on-going TingWall™ renovation project using this Option is the huge IBM building (880,000 sq. ft. of curtain wall) in Rochester, Minnesota.
Option 2 : If the existing mullions are structurally sound and the mullion anchors are questionable due to corrosion caused by water leakage problem, the minor step of replacing and/or reinforcing the existing mullion anchors would be required in addition to Option 1. The end result is still a huge saving compared to the use of a conventional system.
Option 3 : If the existing mullions and mullion anchors are bad but exterior access for installing TingWall™ mullion anchors is available, then, minimum interruption of the interior operation can still be achieved by taking down the old system after the completion of over-cladding with TingWall™. If high performance requirements rule out the use of a conventional Stick System, then TingWall™ is the only system that can be utilized in this condition, since a conventional Unitized System can not be erected without taking down the old system first. In case of property-line or set-back limitations, the over-cladding method using a Stick System may not be applicable due to the interference of the horizontal supporting frame with the old wall. TingWall™'s unique design, with no horizontal supporting member, allows over-cladding using Ting Wall in the situation of property-line limitations.
Option 4 : If the over-cladding method in Option 3 cannot be executed, TingWall™ erection would require the same Steps 1 to 5 as in the conventional renovation. However, the two major problems in Step 6 of the conventional renovation can be eliminated by providing a temporary TingWall™ adapter on the side of the old mullion adjacent to the new mullion. Eliminating the problems in Step 6 constitutes a huge advantage of TingWall™.
Conventional System Vs. TingWall™ renovation
with building vacated
If the building must be vacated during the renovation, the cost to the building owner is huge due to the loss of revenue during the renovation period. Using a conventional system, the building owner often is forced to vacate the building due to the problems in Step 6 above. Vacating the building is normally not required for a renovation project using TingWall™. However, even if the building is to be vacated, the loss of revenue can be greatly reduced through the use of TingWall™ with its unique capability of simultaneous multiple point erection, and the attendant opportunity to substantially reduce downtime.
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