Modified Membrane APP “Cool Roof” Installed
Seven (7) primary roof design solutions were implemented:
- Install new underlayment over the old aggregate surface,
- Replace metal coping cap with integral weatherstripping for glass curtain wall,
- Insure perimeter wind uplift resistance at upper level,
- Provide slip resistant roof surface for window washing equipment on the Sixth Floor,
- Fabricate correct Unistrut mounts for cell tower cabling,
- Cure Second Floor roof leaks at curtain wall base flashing,
- Develop effective and economical “pitch pocket” details.
Aggregate surface was vacuumed and defects repaired prior to installation of underlayment.
Mechanically fastened cement fiber board (above) on the upper level served as a base for heat welded APP modified membranes. To meet budget constraints, 3/8″ thickness was used on the inaccessible upper level and 1/2″ on the main roof area and parapet walls.
Old repairs fastening to the existing walls were ineffective. They simply pulled out of the thin gypsum wall board beneath.
Pitch pocket bases received a layer of smooth and granulated modified membrane. Acrylic flashing cement reinforced with polyester fabric was applied from the penetration extending down over the sides.
The new “Cool Roof” Title 24 approved membrane was fully adhered over Securock fastened directly to wall supports under the existing substrate.
Old coping metal was cupped and deformed where previous workers had peeled it away from the outside edge to install signage, since removed.
New coping was installed including weatherstripping over the exterior glass curtain wall, to block wind blown rain from entering the insulated space behind the glass.
To provide a barrier to wind uplift forces at the perimeter edge detail, 3/4″ Structural plywood was mechanically attached, followed by a half roll of smooth modified membrane, fully adhered.
Custom Unistrut mounts were fabricated to allow for flashings, rather than the prior design with anchor bolts penetrating through the roofing membrane.
The Construction Manager for Cell services needed to avoid repetitive whipsaw of the cabling run in high winds, so we designed anchors to the sides.
We found this rusted roof mounted ventilator with nails through the curb flashing.
Here is the vent, restored and resealed at completion of the Project.