Repair and Replace Damage to the Roof of the City Hall Building

The Roof to be replaced/repaired encompasses app. 8769 square feet and the following is requested: North end of barrel roof shall have rotted overhang removed along with the removal of gable windows and rotted siding. The transition of the barrel roof to gable end shall be secured by fastening with screws and will be sealed and flashed by sprayed polyurethane foam. North gable end will be rebuilt around removed windows with 2x4 and OSB or plywood sheeting. HVAC units on top of roof shall be disconnected by HVAC Contractor removed and set aside. HVAC platform shall have expanded metal grate cut off of platform exposing roof area underneath. Existing specified roof area (barrel roof down to eave, and low slope foam roof on north end) shall be pressure wash cleaned using a high strength industrial cleaner (soap) and pressure washers with a minimum rating of 4000 psi. Loose coatings shall be removed to not have peeling areas. Roof shall be cleaned to be free of dirt, mildew or debris. Saturated foam area around HVAC unit and platform shall be cut out/removed and area shall be allowed to fully dry. Any large bumps in foam will be cut down to create a more uniform even surface. The foam roof area after being cleaned and prepped shall be primed with elastomeric primer designed for rough and irregular substrates. Primer will promote adhesion for spray foam roof system. Roof area will be sprayed will 2 component roof polyurethane foam with a minimum density of 2.8 lb. at a minimum of 1'' thickness across roof system. Spray foam will encapsulate barrel roof, north gable end and low slope foam roof on north side of building. Spray foam will be flashed around parapet walls HVAC unit stands and any roof penetrations present. Spray foam shall be applied in a uniform finish to appear smooth and even across roof surface to not create ponds or dams. After foam has been applied use approved caulking in irregular areas and allows curing. Base coat with acrylic base coat within 24 hr of foam being sprayed. Base coat shall be sprayed on and back rolled at a minimum of 1.9 gallons per square. Modified polyurethane acrylic Top coat shall be spray applied at a minimum of 1.9 gallons per square. Combination of base coat and top coat shall not be less than 27 mils. Contractor will provide non-prorated labor and material warranty that is transferable and renewable for no less than 10 years. Contractor will provide expanded metal grate for HVAC platform and will re-attach metal to frame, working with HVAC contractor to reset HVAC units at appropriate time during city hall non-working hours.

Division 07 -

Thermal and Moisture Protection, Dampproofing and Waterproofing, Thermal Protection.