Sikalastic®-626

One-component, moisture-triggered aliphatic polyurethane

9 months from date of production

Store dry between 35 °F and 77 °F (2–25 °C). Condition material to 50–77 °F (10–25 °C) before using for ease of application

10.8 lb./gal. (1294 kg/m3)

* Substrates: Concrete or cementitious, metals, woods, single-ply or bituminous, stone. Primer required (see Substrate Priming Guide).

Localized Reinforcement: Sika® Flexitape Heavy embedded in 40-45 wet mils of Sikalastic®-626 centered over seams, transitions and properly treated cracks and joints.

Note: Coverage rates provided are optimal and are not guaranteed - coverage rates will vary depending on temperature, surface roughness and porosity, aggregate selection and embedment, and application technique.

Substrate Evaluation
Concrete and cementitious substrates
New concrete shall be allowed to cure a minimum of 28 days. Concrete shall have a minimum compressive strength of 20.7 MPa (3000 psi) and exhibit a minimum tensile bond strength of 1.4 MPa (200 psi). time. Moist or sheet curing methods should be used, as opposed to the use of curing compounds, which may interfere with the bond of the membrane. Inspect the concrete, including upstands, and all areas should be hammer tested. Concrete must be suitably finished, preferably by wood float or steel pan. A power float finish is acceptable where the surface is prepared to avoid laitance (a tamped finish is not acceptable). The surface finish must be uniform and free from defects such as laitance, voids or honeycombing.

Gypsum and Cement based sheathing
Sheathing boards shall be clean, dry and dust free, and shall be properly secured to the structure. Loose, damaged, or contaminated boards shall be removed and replaced.

Brick and stone
Mortar joints must be sound and preferably flush pointed.

Asphalt
Asphalt contains volatiles which can cause bleeding and slight non-detrimental staining. The asphalt must be carefully assessed for moisture and/or air entrapment, grade and surface finish.

Bituminous felt
Ensure that bituminous felt is firmly adhered or mechanically fixed to the substrate. Bituminous felt shall not contain badly degraded areas.

Bituminous coatings
Bituminous coatings shall not have sticky or mobile surfaces, volatile mastic coatings, or old coal tar coatings.

Metals
Metals must be in sound condition.

Paints and coatings
Ensure the existing material is sound and firmly adhered.

Existing Sikalastic® System
The existing Sikalastic® System shall be soundly adhered to the substrate.

Surface Preparation

Concrete and cementitious substrates
Cementitious or mineral based substrates must be prepared mechanically using abrasive blast cleaning or scarifying equipment to remove cement laitance and to achieve an open textured surface (CSP 3-5 per ICRI guidelines). Loose friable material and weak concrete must be completely removed and surface defects such as blowholes and voids must be fully exposed. The amount of embedment coat required may increase over rough or highly porous surfaces.

Repairs to the substrate, filling of joints, blowholes/voids and surface levelling must be carried out. Consult Sika for product recommendations based on project requirements. High spots must be removed by grinding or similar method. Outgassing is a naturally occurring phenomenon of concrete that can produce pinholes in liquid applied materials. The concrete must be carefully assessed for moisture content, air entrapment, and surface finish prior to any roofing work. Particular requirements for priming must also be considered. Installing the primer and membrane either when the concrete temperature is falling or stable can reduce outgassing. It is generally beneficial, therefore, to apply the primer and embedment coat in the late afternoon or evening.

Gypsum and Cement based sheathing
Sheathing boards shall be clean, dry and dust free. Secure loose boards if in sound condition. Damaged or contaminated boards shall be removed and replaced.

Brick and stone
Power wash and use biodegradeable non-sudsing detergent with clean water rinse as required.

Asphalt
Power wash and use biodegradeable non-sudsing detergent with clean water rinse as required. All major cracks should be sealed to allow continuity of the Sikalastic® system.

Bituminous felt
Power wash and use biodegradeable non-sudsing detergent with clean water rinse as required. Treat blisters by star cutting and removing any underlying water. Allow to dry and re-adhere using suitable adhesive.

Bituminous coatings
Remove any loose or degraded coatings.

Metals
Ferrous metals should be thoroughly cleaned by grinding or blast cleaning prior to priming (SSPC-SP3 to near-white metal). Non-ferrous metals are prepared by removing any deposits of dust and oxidation and abrading to bright metal. Wire brushing can be used for soft metal such as lead. The surface must be clean and free from grease which, if present, must be removed with a solvent wipe or wash with detergent, rinse and dry.

Paints/Coatings
Remove any loose or degraded coatings. Ensure the surface is clean and free from grease.

Existing Sikalastic® Systems
Clean the membrane using a water jet at approximately 140 bar (2000 psi) and biodegradeable non-sudsing detergent with clean water rinse. Allow to dry.                                        

Mixing is not required

Detailing and Crack Treatment

Non-structural cracks up to 1/16''- Detail application not necessary. Apply base resin layer per below.

Non-structural cracks between 1/16 inch and 1/4 inch - Rout and seal with Sikaflex® sealant. Apply 40-45 mil resin layer embedded with 3 inch Sika® Flexitape Heavy centered over crack.  Apply base resin layer per below.

Cracks and joints between 1/4 ' and 1''- Rout and seal with Sikaflex® sealant. Apply bond breaker tape sufficient to span width of crack or joint followed by 40-45 mil resin layer embedded with 3'' Sika® Flexitape Heavy centered over crack or joint. Apply base resin layer per below.

Joints greater than 1''- Treat as expansion joint. Consult Sika for recommendations.

Seams and joints (metal, bitumen, single ply) - Apply 40–45 mil resin layer embedded with 3 or 6'' Sika® Flexitape Heavy centered over seam. Apply base resin layer per below.

Transitions between dissimilar materials - Apply 40–45 mil resin layer embedded with Sika® Flexitape Heavy centered over edge. Apply base resin layer per below.

Full surface Application

Mixing not required. Apply base coat of Sikalastic®-626 at a coverage rate of 45sf/gal (~35 mils wft) with a 1/2'' nap phenolic resin core roller (minimum requirement for 10 year material warranty). Material can also be squeegee or spray applied.  Allow to cure 12 hours at 70 °F and 50 % R.H. or until tack free before top resin layer. Keep clean and dry and apply top resin layer within 7 days. If window is exceeded clean with non-sudsing detergent and clean water rinse, and allow to dry prior to application of Sika® Reactivation Primer. Apply second coat of Sikalastic®-626 at a coverage rate of 65sf/gal (~25 mils wft) with a 1/2'' nap phenolic resin core roller (minimum requirement for 20 year material warranty).  

Tile Adhered in a Cementitious Thin-Set Adhesive
A full aggregate broadcast surfacing is required to provide an adhesion key for the tile adhesive. Apply a supplemental 15 wet mils of Sikalastic®-626 resin, followed by a full broadcast of 16–30 or 12–20 kiln-dried sand to refusal, typically 40–50 lbs./100 sf. Remove all loose sand once resin has cured. Do not seal the aggregated surface.

Clean all tools and application equipment with appropriate solvent immediately after use. Hardened and/or cured material can only be removed mechanically