Addendum No. 2 issued April 21, 2023

DPMC Classifications:  C008 or C009 Prime with C029 & C068 Subcontractors

Base Bid work consists of but is not limited to the following:

Parapet Rebuilding (typical classroom):  Erect security fence around exterior of work area including staging space.  Provide scaffolding or other access on the exterior from grade to above roof. Coordinate with School District staff with removal of all classroom items from each room where work will be performed.  During demolition and grinding/cutting, seal off the room from the hallway with zippered dust curtain. When no work is being done, provide security cover over the window openings. Erect temporary roof protection, install a dam at the edge of roof opening to direct roof runoff to roof drain(s) and install wind-resistant cover over opening. Provide fire protection and extinguishers at all areas during the work. Consult with local fire department about fire safety during cutting work (sparks may be generated) and other operations. Remove plaster from interior surfaces at work area. Install temporary shoring in the top floor room and the rooms directly below the work area.  This includes shoring on 3 floors. Remove masonry on exterior parapet wall above the roof down to the top of the window frame. Document existing conditions, particularly the anchoring for the terra cotta and the beam-to-roof deck connection. Cut the concrete connection between the back of the steel I-beam and the concrete roof deck with a large diamond saw.  It is likely that a specialty company will be needed to do this 15" vertical cut.  Cut the existing steel beam into sections.  Remove these pieces of steel beam and the steel bearing plates at each end of the beam. Rebuild masonry at top of wall where loose or damaged at ends of opening and at the brick columns between the windows. Install new bearing plates at bearing points at ends of beam location.  Install new steel I-beam.  Size may be slightly different than original to meet modern specs and to adapt configuration with beam in slightly more recessed position over the bearing walls.  Crane will probably be needed to lift beam in place. Provide anti-rust coating on all surfaces of beam and bearing plates. Provide new stainless steel dowel anchoring system to tie steel beam to roof deck concrete beams.  Provide additional mounting plates and shelves as necessary to support new parapet wall construction. Repair roof deck and the system that provides taper for the roof.  In order to direct water to the roof drains, a taper system was required. The roof deck is level and a taper was added by installing light-weight cinder concrete.  Where the light-weight concrete is exposed during the work, repair damaged sections of the concrete. Construct new parapet wall with CMU masonry and GFRC cast panels.  Install vertical reinforcement in wall assembly and tie parapet to steel frame and masonry.  Repair roofing system as needed and install new roof flashing system.  During all phases of the construction, provide vertical expansion joints at each end of the steel beam so there is a completely-open break between the new parapet wall and the old walls.  Install slip set stabilizers to provide lateral stability of the two sides of each expansion joint.  Install backer rod and sealant in the joints. Remove temporary shoring at each floor. Repair wood window frame as needed. Remove and reset window assemblies as needed to accomplish the repairs. Install stainless steel expanded metal mesh in areas to be replastered at top of window and where shoring was installed.  Replaster these areas. Repaint areas where work was performed per guidance from the Architect. Leave classrooms, hallways and other affected interior areas broom clean. All other indicated work.

Salvage of Diamond Terra Cotta Panels and Reuse at Lower Window Openings.  

Selected Areas:  At terra cotta panels between 2nd floor and 3rd floor windows, cracks indicate fractures caused by oxide jacking of steel beam pushing out horizontally and/or vertically. Provide scaffolding or lift for access to work areas. Salvage matching terra cotta pieces during demolition of the parapet wall. Remove the diamond panels from the donor carefully without breaking any panels.  The best approach will be to dismantle the parapet wall working from the top and back down and towards the face.  It should be possible to remove any metal anchors that are encased in the terra cotta and the backup masonry. Remove the existing panels in the area receive the transplanted panels. Clean any mortar and caulk from the panels and reset them in the opening. Remove rust from the exposed steel beam down to shiny metal and apply anti-rust coating. Clean any mortar and caulk from the panels and reset them in the opening. It will be necessary to provide some stainless steel anchors to insure that the panels will not work loose from the backup.  Repoint all joints in terra cotta panel. All other indicated work.

Masonry Restoration for All Areas:

Clean all masonry surfaces.  Use the mildest method and materials which are reasonably effective.  Do not erode, abrade, damage or acid burn the masonry surfaces. Repoint all joints in existing terra cotta panels and between terra cotta pieces and brickwork. Repoint all joints in exposed brickwork on the main elevations of the building.  Exclude from this any brick areas which were previously repointed. Perform small masonry repairs at designated locations on the building. Perform repairs on exposed foundation of the building as needed on all four elevations. Apply a coating to all terra cotta pieces and terra cotta replication pieces made with GFRC.  Match the existing color and surface texture of the terra cotta.  Use a coating which is breathable and has a tested history of successful coating of terra cotta and GFRC material. Do not paint or coat the mortar joints. All other indicated work.

Alternate Bid(s):  Alternate Bid No. 1 - Chimney Restoration

Single Overall Contract includes:  All work in accordance with drawings, Specification Sections and in accordance with Contract Documents.