Sikalastic®-621 TC
SINGLE COMPONENT RESIN FOR SIKALASTIC® ROOFPRO ROOFING SYSTEMS
Sikalastic®-621 TC is a cold-applied, highly elastic, aliphatic, single component, moisture-triggered polyurethane top coat resin designed for easy application as part of Sikalastic®-621 RoofPro roofing systems.
- Proven technology – over 30 year track record
- One component – no mixing, easy and ready to use
- UV resistant – Highly reflective (RAL9016) and resistant to yellowing
- Cold-applied – requires no heat or flame
- Seamless roof waterproofing membrane
- Compatible with Sika® Reemat Premium – easy to detail
- Fast curing – free from resin damage almost immediately on application
- High elastic and crack-bridging – retains flexibility even at low temperatures
- High root resistance
- Easily re-coated when needed – no stripping required
- Good adhesion to most substrates – see primer chart
- Vapour permeable – allows substrate to breathe
- Strong resistance to common atmospheric chemicals
Usage
- Sikalastic® RoofPro Direct, Recover, Built-Up, Inverted, and Vegetated systems for both new construction and refurbishment applications
Advantages
- Proven technology – over 30 year track record
- One component – no mixing, easy and ready to use
- UV resistant – Highly reflective (RAL9016) and resistant to yellowing
- Cold-applied – requires no heat or flame
- Seamless roof waterproofing membrane
- Compatible with Sika® Reemat Premium – easy to detail
- Fast curing – free from resin damage almost immediately on application
- High elastic and crack-bridging – retains flexibility even at low temperatures
- High root resistance
- Easily re-coated when needed – no stripping required
- Good adhesion to most substrates – see primer chart
- Vapour permeable – allows substrate to breathe
- Strong resistance to common atmospheric chemicals
Packaging
19 L (5 gal.) metal pail
Colour
White (RAL 9016), Pearl Grey, Steel Grey, Mushroom, Copper Green;
custom colours available with minimum order
Product Details
APPROVALS / CERTIFICATES
As part of Sikalastic®-621 RoofPRO Roofing System:
- FM Approval Standard 4470 for Class 1 Roof Covers
- ASTM E-108-00 Spread of Flame meets Class A at a slope of 1 in 12
- Simulated wind uplift pull testing meets up to Class 1-990
- Simulated hail damage testing meets rating of SH-Severe Hail
- Miami-Dade County NOA for Roof Systems over Concrete and Steel Decks
- USGBC LEED rating: Conforms to LEED SS Credit 7.2 for Heat Island Effect - Roof with SRI >/=78
- Meets ASTM D7311-07: Standard Specification for Liquid-Applied, Single-Pack, Moisture-Triggered, Aliphatic Polyurethane Roofing Membrane.
Composition / Manufacturing
One-component, moisture-triggered aliphatic polyurethane
Shelf Life
9 months from date of production
Storage Conditions
Store dry at temperatures ranging between 2 °C and 25 °C (35 °F and 77 °F). Condition product to temperatures between 10 °C and 25 °C (50 °F and 77 °F) before using and for ease of application.
Density
~1.44 kg/L (~12 lb/US gal.) at 23 °C (73 °F) |
Solid content by volume
81% | (ASTM D2697) |
Volatile organic compound (VOC) content
183 g/L | (ASTM D2369-81) |
System Structure
Please refer to Sikalastic®-621 System Data Sheet
Tensile Strength
Please refer to Sikalastic®-621 System Data Sheet | (ASTM D751) |
Tear Strength
Please refer to Sikalastic®-621 System Data Sheet | (ASTM D751) |
Resistance to Static Puncture
Please refer to Sikalastic®-621 System Data Sheet | (ASTM D5602) |
External Fire Performance
Class A | (ASTM E108) |
Chemical Resistance
Strong resistance to a wide range of reagents including paraffin, petrol, fuel oil, white spirit, acid rain, detergents and moderate solutions of acids and alkalis. Some low molecular weight alcohols can soften the material.
Contact Sika Canada for specific information.
Solar Reflectance
0.87* | (ASTM C1549) |
*All values refer to the initial (properly cured, non-weathered) status of Sikalastic®-621 TC white (RAL 9016)
Solar Reflectance Index
≥ 108* | (ASTM 1980) |
*All values refer to the initial (properly cured, non-weathered) status of Sikalastic®-621 TC white (RAL 9016).
Service Temperature
–30 °C (–22 °F) min. / +80 °C (176 °F) max.
Application
Ambient Air Temperature
5 °C (41 °F) min. / 35 °C (95 °F) max.
Relative Air Humidity
80 % R.H. max.
Substrate Temperature
5 °C (41 °F) min. / 60 °C (140 °F) max
Dew Point
Beware of condensation. The substrate and uncured coating must be ≥ 3 °C (5 °F) above dew point.
Substrate Moisture Content
≤ 4 % pbw moisture content.
Test method: Sika®-Tramex meter
No rising moisture according to ASTM (Polyethylene-sheet).
Pot Life
Sikalastic®-621 TC is designed for fast curing. High temperatures combined with high air humidity will increase the curing process. Thus, material in opened containers should be applied immediately. In opened containers, the material will form a film after one (1) hour approx. (20 °C, 68 °F / 50 % R.H.).
Waiting Time / Overcoating
Ambient conditions | Minimum waiting time overcoating |
4 °C (40 °F) / 50 % R.H. | 14 hours |
10 °C (50 °F) / 50 % R.H. | 6 hours |
21 C° (70 °F) / 50 % R.H. | 5 hours |
*After seven (7) days the surface must be cleaned and primed with Sika® Reactivation Primer before continuing.
Note: Times are approximate and will be affected by changing ambient conditions particularly temperature and relative humidity.
Applied Product Ready for Use
Ambient conditions | Rain resistant | Touch dry | Full cure |
4 °C (40 °F) / 50 % R.H. | 10 minutes* | 12 hours | 24 hours |
10 °C (50 °F) / 50 % R.H. | 10 minutes* | 6 hours | 18-24 hours |
21 °C (70 °F) / 50 % R.H. | 10 minutes* | 4 hours | 12-18 hours |
Note: Times are approximate and will be affected by changing ambient conditions particularly temperature and relative humidity.
Yield
Sika® Reemat
1.96 m2/L - 0.51 mm (80 ft2/US gal. - 20 mil) w.f.t.
1.3 m2/L - 0.76 mm (53 ft2/US gal. - 30 mil) w.f.t.
1.1 m2/L - 0.89 mm (45 ft2/US gal. - 35 mil) w.f.t.
0.86 m2/L - 1.14 mm (35 ft2/US gal. - 45 mil) w.f.t.
SUBSTRATE PREPARATION
All substrate surfaces shall be clean, dry and sound. Acceptable substrates include: sound concrete and cementitious screed, metals, wood, modified bitumen, mineralized felt, EPDM, hypalon, TPO, sprayed-polyurethane foam, brick and stone, slate and tile, and existing liquid-applied membranes. Reference separate System Data Sheet for specific surface preparation requirements.
Primer
Apply primer of a type suitable for the substrate. Allow primer to cure completely before applying Sikalastic®-621 TC resin. Reference separate System Data Sheet for specific primer recommendations.
MIXING
No mixing necessary
APPLICATION
Sika® Reemat - Base Resin
Apply Sikalastic®-621 TC resin to the primed substrate surface by means of 12.7 mm (1/2 in) nap phenolic resin core roller or brush at the specified application rate to achieve a uniform and consistent wet mil thickness (reference separate System Data Sheet). Material can also be squeegee- or spray-applied, in which case it should also be backrolled. Apply Sika® Reemat into the wet embedment resin and roll the scrim to achieve full saturation and embedment. Reemat shall be cut to conform to substrate transitions and flashing conditions, with a typical 50.8 mm (2 in) reinforcement overlap. Resin shall saturate the Reemat from below. Apply additional Sikalastic®-621 TC resin as required to ensure full scrim embedment. Allow to cure completely before applying subsequent resin layers.
Sika® Reemat - Intermediate and Top Resin
Apply Sikalastic®-621 TC resin to the cured Sikalastic®/Reemat base layer by means of 12.7 mm (1/2 in) nap phenolic resin core roller or brush at the specified application rate to achieve a uniform and consistent wet mil thickness (reference separate System Data Sheet). Material can also be squeegee- or spray-applied, in which case it should also be backrolled. Allow to cure completely before applying any subsequent resin layer, if specified.
CLEAN UP
Clean all tools and application equipment with appropriate solvent immediately after use. Hardened and/or cured material can only be removed mechanically.