Sikalastic 641, 15L

It is recommended that the product be stored in warm conditions (+20 °C (+68 °F)) before application at temperatures below +10 °C (+50 °F).

+5 °C (+41 °F) min / +40 °C (+104 °F) max

20% r.h. min / 85 % r.h. MAX

Beware of condensation! The substrate and the applied product must be at least +3 °C (+37 °F) above the dew point to avoid the risk of condensation or efflorescence on the membrane surface.

+5 °C (+41 °F) min. / +60 °C (+140 °F) max.

≤4 % moisture content. Test method: Sika®-Tramex No rising moisture according to ASTM (polyethylene film test).

~1 hour (+20 °C (+68 °F) / 50 % r.h.)

These times are approximate and could be influenced by changing ambient conditions, especially temperature and relative humidity.

Material from open containers should be applied immediately. In open containers, the material will film in ~1 hour.

1 Four days after applying the first coat, the surface must be cleaned and primed with Sika® Reactivation Primer before proceeding.

These times are approximate and could be influenced by changing ambient conditions, especially temperature and relative humidity.

1 The impact of rain or heavy downpours can damage or damage the unreinforced membrane.

2 Application at higher than recommended film thicknesses may result in a prolonged "soft" feel to the coating. This will eventually strengthen.

Note: These times are approximate and could be affected by changing ambient conditions, especially temperature and relative humidity.

Generic

All dust, loose and friable material must be completely removed from all surfaces prior to application of the product and associated system products, preferably with vacuum equipment.

To confirm adequate surface preparation and adhesion of Sikalastic®-641 preliminary tests shall be carried out prior to full application.

Concrete and cementitious substrates

The substrate must be structurally sound, clean, dry and free of contamination such as dirt, oil, grease, other coatings, cement laitance, surface treatments and friable material.

New concrete should be cured for at least 28 days.

Substrates must be mechanically prepared using appropriate substrate preparation equipment to remove cement laitance and obtain an open textured bond surface profile appropriate for the thickness of the product.

Roughness can be removed by grinding.

Parts of concrete with poor adhesion and friable particles must be completely removed, and surface defects such as holes or voids must be fully exposed.

Substrate repairs, filling of joints, holes / voids and surface leveling must be carried out using suitable products from the Sikafloor®, SikaDur® and SikaGard® ranges. The products must be allowed to cure before applying Sikalastic®-641.

Brick and stone

Clean thoroughly by pressure washing and allow to dry. Use Sika® Biowash if necessary. See the individual product data sheet. Repair broken, cracked or missing pieces.

Ceramic tiles

Make sure all ceramic tiles are in good condition and are securely attached to the substrate. Replace broken, cracked or missing pieces. Wash with a pressure jet and use Sika® Biowash if necessary.

Asphalt

Wash under pressure and allow to dry. All major cracks must be sealed to allow continuity of the Sikalastic®-641 system. Asphalt should be carefully evaluated for moisture and/or entrained air, roughness and surface finish prior to any subsequent application. Any priming requirements should also be considered.

Bituminous membranes

Ensure that the bituminous membranes are glued or mechanically fastened to the base layer. Wash under pressure and allow to dry. The blisters will be removed or cut into a star shape, and the water below will be removed and allowed to dry. Severely degraded surfaces must be replaced.

Single layer membranes

Different types of membranes can be covered. Contact the Sika technical department for further information.

Bituminous coatings

Bituminous, volatile mastic or old tar-based coatings must not be sticky and detached from the substrate. Remove degraded or detached coatings.

Metals

Ferrous metals must be in good condition. Surfaces must be clean, free of rust, oil, grease, exfoliated or degraded existing coatings, etc. Prepare surfaces for a bright metallic finish using proper preparation techniques, taking environmental conditions into account.

Non-ferrous metals must be in good condition. Remove any traces of dust and oxidation and sand to a shiny surface. The wire brush can be used on soft metals such as lead. The surface must be cleaned and degreased with appropriate solutions. Wash with detergent, rinse and let dry

Wood

Wood roofs and wood-based panels must be in good structural condition, firmly glued or mechanically fastened.

Wood and wood panels require a full coat of Sikalastic® Carrier prior to application of the Sikalastic®-641 system. The substrate should then be treated as a felt roof. Small wooden protrusions can be treated locally by planing or sanding to achieve a smooth surface.

Paints/coatings

Remove all exfoliated or degraded coatings. Remaining coatings can be re-coated if well bonded. Make sure the surface is clean and free of oil, grease, etc.

Existing Sikalastic®-641 systems

Clean the membrane using a water jet with a pressure of approx. ~14 N/mm2 (2000 psi) including detergent, then rinse thoroughly and allow to dry.

Sikalastic®-641 is ready to use. Before application, mix for a minimum of 1 minute using the mixing paddle or other suitable equipment to mix the liquid and all the colored pigment until a uniform color is obtained. Overmixing should be avoided to minimize air entrainment.

Strictly follow the application steps defined in the application procedure, application manuals and work instructions which must always be adjusted to the actual site conditions.

Generic

Always start with the details before applying to horizontal surfaces.

primer

Pour the properly mixed primer onto the prepared substrate and apply with the appropriate brush or roller. Make sure a continuous, non-porous layer covers the substrate. Confirm primer wait/overcoat time has been reached before applying successive products. See individual primer data sheet.

The base layer

Apply mixed Sikalastic®-641 to the prepared substrate with the same width as Sika® Reemat Premium, evenly, by roller or brush, at the required consumption rate in 2 perpendicular directions.

arming

Roll on Sika® Reemat Premium reinforcement while Sikalastic®-641 is still wet, making sure there are no bubbles or creases in the reinforcement. Reinforcement overlaps must be at least 50 mm (1.97 in). The recommendation is to work 1.0m (3.28 ft) once per length, applying the first coat and embedding the reinforcement.

The final layer

Apply mixed Sikalastic®-641 to the prepared substrate with the same width as Sika® Reemat Premium, evenly, by roller or brush, at the required consumption rate in 2 perpendicular directions. Confirm overlay times prior to application.

Make sure each application/coat is clean and dry before applying the next coat.

Note: The material will dry on the surface in approximately 30 minutes, depending on temperature and humidity conditions. Always maintain a wet edge and finishing surface as work continues. Returning to areas that are partially dry may damage the surface.

Clean tools and equipment with Thinner C immediately after application. The hardened material can only be cleaned mechanically.