SBS Modified Bitumen - Page 2

SBS Modified Bitumen Specifications

A.

Never use wet or damaged materials.

B.

Never apply any roofing materials during rain or snow, or to wet or damp surfaces. Moisture trapped within the roofing system may cause severe damage to the roofing membrane, insulation and deck.

C.

Take special care when applying any roofing felt in cold weather. Check the temperature of the asphalt at the mop or spreader to determine that it is at the proper temperature.

D.

Heed the specific cold weather application procedures in this manual.

E.

Always start application at the low edge of the roof per the individual specification diagram

F.

Never mop ahead of the modified bitumen rolls more than six feet (1.83 m) and, in temperatures below 50°F (10°C), no more than four feet (1.22 m). Observe temperature guidelines for asphalt application.

G.

When using mechanical bitumen applicators or felt laying equipment, be sure that all orifices are open.

H.

All roofing felts should be well set into the hot asphalt utilizing a squeegee or some other device. All ply felts shall be rolled (not "flown") into the hot asphalt.

I.

SBS modified bitumen sheets shall be rolled or scrolled into a full mopping of hot asphalt. Back-mopping and flopping into a full coating of asphalt is also acceptable for certain SBS products. Base sheets and cap sheets with polyester reinforcement must be allowed to relax in an unrolled position prior to installation.

J.

Do not mix different grades of asphalt or dilute an asphalt with any other material.

K.

Heat the asphalt according to the manufacturer’s recommendations. Check the temperature of the asphalt at the kettle and at the point of application. Have accurate thermometers on the roofing kettles. Adhere to the guidelines for the heating of asphalt that are outlined in this manual.

L.

Always use the proper grade of asphalt. SBS membranes require the use of Type III or IV asphalt.

M.

It is essential that traffic be minimized on a freshly laid roof, while the asphalt is still fluid. Asphalt displacement through the porous fiber glass ply felts can result from rooftop traffic during asphalt "set" time. Depending on specific job factors, this set time can be as long as 45 minutes. Asphalt displacement can result in "phantom" leaks and blistering of the membrane.

N.

Do not use coal tar pitch or coal tar asphalt with any of JM’s modified bitumen products. They are not compatible.

O

Do not use traditional cut-back asphalt cements under SBS modified bitumen products. The use of these mastics over the top of SBS products, to strip in or to cover nail heads, is acceptable, however the MBR cement products are preferred.

P.

Install the entire roofing system at one time. Phased construction may result in slippage of felts due to excessive amounts of asphalt between the plies of felt. Blisters due to entrapment of moisture are also a common problem, as well as poor adhesion due to dust or foreign materials collecting on the exposed felts of an incomplete roofing system.

Q.

Always install a water cut-off at the end of each day’s work to prevent moisture from getting into and under the completed roof system. Water cut-offs should be completely removed prior to resuming work.

R.

Always comply with published safety procedures for all products being used. See the "Introduction" section of the current JM Commercial/Industrial Roofing Systems Manual, MSDS, and container labels for health and safety recommendations.