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The Godfrey Hotel

The Godfrey Hotel in Boston, formerly 59 Temple Place, served as a multistory office building with first floor commercial space.  The Godfrey Hotel was created by combining as one, the four-story Amory Building and the eleven-story Blake Building.  Both buildings, built in the same time frame over 100 years ago shared a common wall and occupied the full city block between West Street and Temple Place along Washington Street in the center of Boston’s retail district.  Both buildings underwent a complete interior and exterior makeover during the conversion to the iconic Godfrey Hotel.

CBI Consulting Inc. was the Engineer of Record for restoration of the façade.  The Amory building façade consisted of decorative galvanized break metal, painted several times in its life.  Environmental wear and tear exacerbated by the traverse of heavy footed window washers had opened seams in the metal and altered the shape of the thin metal veneer in many areas.  To meet budget constraints and to retain as much of the historical fabric as possible, the original metal was retained and refurbished to start the next 100 year cycle.

The Blake Building façade is one of the few remaining outstanding terracotta veneers along Washington Street in Boston.  At one time, a stroll along the streets of downtown Boston exposed passersby to numerous magnificent terracotta facades.  Reduced in number by development and age, there are fewer than ten remaining today.

100_2978 straightWhen first studied it appeared the terracotta was beyond salvage.  Devoted to preserving elements of history, the site developer funded an additional study to determine the extent of salvage of individual elements.  CBI developed a “deconstruct mockup” process to view a portion of the existing wall as a representative sample so rather than building a mockup wall section of a typical bay to study the cost of a detailed rehabilitation, the process consisted of quantifying through test cuts and excavating terracotta elements, some of which were repairable and others beyond salvage.  Replacement products that were considered included traditional terracotta, glass fiber reinforced polymer (GFRP), and precast concrete.

IMG_2325The “deconstruct mockup” process revealed that on a floor by floor basis, stones were bearing one on another and at each floor level, supported on steel brackets which were a component of the structural steel sub-frame.  The use of GFRP elements, although economical, are not easily adaptable as bearing pieces and would mean removing existing stones that could otherwise remain, simply to allow full floor
 height run of GFRP between steel brackets.  As to terracotta, the cost and timing for the more traditional terracotta was discounted because of the limited replacement quantities, and that over nine different shapes/sizes would be needed.  A local pre-caster responded with a desirable turnaround time for concrete replication and provided the opportunity to use multiple templates without objectionable time and cost constraints.

Some of the existing terracotta could remain, but required repair.  Working with a restoration contractor, a process of spall repair and crack routing was developed which allowed some stone to remain in place while being repaired from the exterior.  Repair from the exterior did not negate the need to properly secure these stones to prevent lateral displacement.

Close up of detail before

Close up of detail before

The next task was to develop a method to secure terracotta pieces that were intact yet no longer secured by the original ¼” square ties that had long since deteriorated as a result of environmental corrosion.  Some ties simply corroded through their cross section resulting in no damage to the stone (terracotta) so the stones could be reused.  In other cases, oxidation corrosion of the steel (rust jacking) caused pressure so extensive that the stone split or spalled, requiring replacement.

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Close up of detail before

In order to salvage as much original terracotta as possible, an effort was set in motion to determine how to best secure the stone.  The first approach was to use blind anchors to secure the stone from the exterior by drilling through the stone to secure the piece to the supporting structure of the wall.  The author has used this approach with success in other structural applications.  In this use however, even the smallest anchors were too large to reliably engage the structural steel cross section within the wall.  The next approach was to attach a small expanding anchor as one might obtain from Blok-Lok.  This turned out to be another failed exercise.  Lastly, we worked with the contractor to explore the use of helical anchors.  Test installation using blind installation conditions followed by pull tests and exposing the anchor attachment within the wall for observation were successful.

Anchors could be drilled from the exterior to anchor to the masonry substrate or in another condition to secure to the wood framing of the abandoned window counterweight boxes that were part of the original construction.  Timing the installation of the helix anchor to the complete demolition of the original building interior allowed observation of the anchor installation from the interior to be sure that the substructure intended to secure the anchor was adequate.  In situations where the substrate masonry was inadequate, poor masonry would be removed and rebuilt to provide a more robust helical anchorage.  This exercise determined that re-securement of the stone to the substructure was practical.

The developer was renovating the entire building exterior and started by gutting the finishes to the steel structure.  Having the interior exposed also allowed observation and reconciliation of anomalous structural conditions.  At the eighth floor level on the Temple Place elevation, it was observed that several bolted connections of the original construction had been consistently missed.  Those deficiencies were addressed by welding.  Along the same line of lintel stones, the vertical leg of the steel lintel support angle prevented the introduction of the helical tie.  To address this condition, the engineer and contractor explored two options.  The first was the use of blind anchors set from the interior.  The second option consisted of drilling 3/8” diameter anchors into the rib of the terracotta “egg crate” type casting to set a threaded stainless steel rod in epoxy.  Drilling the steel to set the blind anchor was difficult [because of constructability space restraints] and the contractor opted for the epoxy set threaded rod.

Looking out from the interior

Looking out from the interior

Having the benefit of the “deconstructed mockup” and with mast climbers in place to facilitate closer observation of the façade, the team was able to salvage more than 75% of the existing terracotta.

The original estimate of 25% replacement on which the job was budgeted and approved, was all the more conservative and ultimately reduced to approximately 13% replacement.

Close cooperation between the Owner, construction team, and CBI resulted in a successful project experience, which was recently awarded a 2016 Boston Preservation Achievement Award.

http://www.bostonpreservation.org/programs/awards-2016.html