Window Caulking Replacement

                                          Window Caulking Replacement

The Contractor is to provide all labor, materials, equipment, scaffolding and accessories, etc. as required to remove existing foam backing and caulking, install new closed cell backer rod and re-caulk approximately 308 windows at the Federal Medical Center Carswell.  This work will be completed at various elevations surrounding the exterior of the hospital building.

Removal:

Remove and properly dispose of all existing caulking and backer-rod materials from windows.

Application:
Apply 3100 linear feet of closed cell backing rod and caulking  at joint between window frames mullion using Sonolastic NP1 or 2 Polyurethane Joint Sealant in medium bronze finish or approved equal.

Apply 600 linear feet of caulking at joint between window glass gaskets and window  frames mullion using Sonolastic NP1 or 2 Polyurethan Joint Sealant inmedium bronze finish or approved equal.

Apply sealant in accordance with manufacture's written instructions.  Mask edges of joint where irregular surface or senstive joint border exists to provide neat joint.  Apply sealant in continuous beads.  Apply sealant using gun with proper size nozzle.  usufficient pressure to fill voids and joints solid.  Form surface sealant with full bead, smooth, free from ridges, wrinkles, sags, air pockets, embedded impurities.  Tool exposed surfaces before skinning begins togive slightly concave shape.  Remove excess compound promptly as work progesses and upon completion.

Clean adjacent surfaces immediately and leave Work neat and clean.  Remove excess and droppings, using recommended cleaners as work progresses.  Remove masking tape after intial set sealant.

Provide appropriate sized closed cell backer-rod as needed.

Execution:

Examine joint sizes and conditions to extablish correct dedpth to width relationship for installation of backup materials and sealants. 

Clean bonding joint surfaces of harmful matter substances including dust, rust, oil, grease, and other matter which may impair work.

Ensure joint surfaces are dry and frost free.

Prepare surfaces in accordance with manufactures's directions.

Do not proceed with installation of joint sealants when ambient and substrate temperature conditions are outside limits premitted by joint sealant manufacture or when joint substrates are wet.

Do not proceed with installation of joint sealants until contaminats capable of interfering with adhesion are removed from joint substrates.

Conform to manufacture's recommended temperatures, relative humidity, and substrate moisture content for application and curing of sealants including special conditions governing use.

Joint cleaner - Non-corrosive and non-staining type, compatible withjoint forming materials and sealant recommended by sealant manufacture.

The performance period of the contract shall be 45 working days from the time the contract is awarded weather perfmitting.