NovaTuff RC-105 Liquid Seam Tape – Metal Roof Repair

Product Information

Download TDS NovaTuff RC-105 Liquid Seam Tape


NovaTuff RC-105 is a flexible two-part epoxy, brush grade sealant used in metal roof repair to seal and waterproof laps and joints in metal roofs. Designed as a liquid seam sealer, this compound chemically cures into a flexible, rubber-like membrane that is UV stable and withstands thermal shock.

Application Areas:

NovaTuff RC-105 is an exterior water tight sealer primarily used with NovaTuff RC-100 on metal roof repair to seal vertical seams without the use of fabric and also for waterproofing fasteners. It can also be used as a standalone metal roof repair product for waterproofing laps, seams, penetrations, fasteners, and more. NovaTuff RC-105 can also be applied to wet surfaces and can cure underwater if necessary.


Surfaces must be cleaned free of grease, oil, films, dust, or any other contaminants.  All surfaces must be pressure-washed to remove any barrier films.  Metal must be free of mill scale, oils, rust, etc. These preparation procedures are general guidelines. Detailed preparation methods are available through SSPC at or 412-281-2331 or NACE at or 281-228-6200.


The mixing of Part A and B is very important!  NovaTuff RC-105 has a mixing ratio of 4 parts “B” to 1 part “A” (4:1).  Use a power drill and mixing paddle to thoroughly combine both parts.  Mix for at least one minute per gallon.  Allow idle activation time for a minimum of 10 minutes. Note: Partial mixtures will only work if part “B” is thoroughly mixed first.


NovaTuff RC-105 can be applied using a 2″ chip brush or a putty knife. NovaTuff RC-105 must be applied at a  rate of 64 to 80 wet mils and then top coated with NovaTuff RC-100 at a minimum rate of 16 wet mils. If applying NovaTuff RC-105 as a standalone repair product for waterproofing laps, seams, penetrations, or fasteners it must be applied at a minimum rate of 96 wet mils. Note:  Apply only when air temperature is 32° F and rising with no forecasted freeze or snow for a minimum of 48 hours.

Clean Up:

Application equipment should be cleaned immediately with Lacquer Thinner.  Use White Vinegar to clean hands and skin.  Do not allow NovaTuff RC-105 to remain on tools!  Once it sets and is cured, it is difficult to remove.


5 gallon unit:

·         One  6 Gal pail containing 4 gallons of Base  (Part “B”)

·         One 1 Gal can full containing Activator   (Part “A”)

1 gallon unit:

·         80% of a full gallon by volume 1 Gal can containing 4 parts of Base  (Part “B”)

·         1 Qt can containing Activator   (Part “A”)

(Approximate weight of product: 11.5 lb/gal)

Testing and Misc:

·         Colors: NovaTuff standard color (White and also Gray or Tan)

·         Physical Contents: Solids – % by weight –  83%

·         Mixing Ratio: 4 Parts “B” to 1 Part “A” (4:1)

·         Permeance (ASTM D-1653):   0.4 perms

·         Water Swelling (ASTM – D471):  0.9%

·         Tensile Strength (ASTM D-638):  1780 psi / 180% elongation

·         Adhesion: 290 lbs./sq. in.

·         Tear Resistance (ASTM D-624):  170 lb/in

·         Fungi Resistance (ASTM G-21): 0 (Pass)

·         Low Temperature Flex -15° F (ASTM D-522) : Pass

·         1000 hr. accelerated weathering (ASTM D-498):  Pass (No cracking or Checking)

Curing Time:

·         Pot Life: 2 hrs @ 80 ºF

·         Drying Time: 5 hrs @ 80 ºF

·         Complete Cure: 7 days @ 80 ºF

Shelf Life and Storage Conditions:

NovaTuff RC-105 has a 12 month shelf life if unopened and stored between 40 degrees Fahrenheit and 90 degrees Fahrenheit. Do not allow products to freeze.


For further assistance, contact one of our technicians via phone or e-mail:

(512) 617-7333


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