Moisture Control | Roof Decks | Rigid Insulation | Roof Membranes

ROOF MEMBRANES

Types Of Roof Decks that Require Mechanically Fastened Base Sheets
· Cement Wood Fiber Panels · Steel Panels
· Lightweight Insulating Concrete · Precast Concrete Panels
· Poured Gypsum Concrete* · Wood Panels or Wood Planks
· Precast Gypsum Panels* · Tecktum
* Certain gypsum decks may need to have fastener holes predrilled in order for the deck to be considered nailable.

Nails Acceptable for Mechanically Fastening Certain Roof System Components
Unless otherwise specified, the minimum type nails shall be at least 12 gauge galvanized, 1” large head, annular threaded nails, or ring shank nails for fastening the first layer of reinforcing sheets or insulation boards to nailable decks; for back nailing membrane reinforcing sheets; and for fastening flashing reinforcing sheets. Nails are required to penetrate through the structural substrate a minimum of .25” or into the structural substrate a minimum of .75”.

UK5 KraftFelt Separating Sheet
Roof decks that may allow asphalt to migrate through the deck require a nailed or stapled separating sheet of UK5 KraftFelt attached to the deck. The KraftFelt shall be installed as the first layer, and as a separating sheet between the deck and the mechanically fastened base sheet or insulation. Fasten the KraftFelt with minimum side laps of 2” and end laps of 6” offset at least 36”.

Fields Asphalts
Correct asphalt application temperature or viscosity shall be maintained so as to preserve the quality of the asphalt and so as to ensure thorough lamination of the reinforcing sheets. Overheating or maintaining asphalts at elevated temperatures will damage the asphalt as well as create a fire danger.

Required Guidelines for Heating Asphalts
1. Heating equipment temperatures shall not exceed 120°F for ambient applied asphalts.

2. Heating equipment temperatures shall be maintained at less than 25°F below the flash point for hot applied asphalts.

3. Asphalt shall not be kept at high temperatures for prolonged periods.

4. Asphalt shall not remain in open rooftop containers for long periods of time.

5. Asphalt pipelines shall be insulated to aid in maintaining the correct asphalt temperature on the roof.

6. Asphalt shall be circulated while it is heating.

In order to maintain the correct application viscosity for ambient applied cutback asphalts, the applicator shall employ equipment to maintain the cutback asphalt at a minimum of 110°F when measured at the point of application.

In order to maintain the correct application viscosity for hot applied asphalts, the applicator shall follow the correct EVT (Equiviscous Temperature) guidelines. EVT is the temperature at which hot applied asphalt has the correct viscosity for installation and coating of the reinforcing sheets. The EVT range is 25°F above or below the EVT, thus giving a maximum range of 50°F. The EVT application temperature range is measured in the asphalt mopping cart or machine spreader at the time of application. The EVT for hot applied asphalt is as follows: For cart applications 125 centipoise; and for machine applications, 75 centipoise.

Asphalt Application
Asphalt application includes the correct rate of speed at which the asphalt is applied as well as the method of application such as by brushing, squeegeeing, mopping, spraying, or machine application. Heated asphalt better penetrates and fuses with the asphalt in the membrane reinforcing sheets, which better laminates the sheets together. Correct application temperature is vital for the construction of a quality, well laminated roof system membrane. The correct asphalt temperature must be maintained in order to ensure good lamination of the reinforcing sheets during installation.

Temperature effects the viscosity and flow characteristics of asphalt, and therefore, the weight or application quantities. Temperatures that are too high can result in asphalt that has low viscosity and greater flow characteristics when applied, and thus can cause:
1. Lighter asphalt weight applications.
2. Incomplete asphalt coverage.
3. Asphalt voids between reinforcing sheets.
4. Diminished asphalt waterproofing qualities.
5. Reduced asphalt weathering durability.
6. Project site safety hazards.

Temperatures that are too low can result in asphalt that has high viscosity and lower flow characteristics when applied, and thus can cause:
1. Heavier asphalt weight applications.4. Slippage of the reinforcing sheets.
2. Poor adhesion.

5. High expansion properties.
3. Inadequate lamination of the reinforcing sheets.

6. Low asphalt tensile strength.