Sikalastic®-625
Polyurethane liquid applied reinforced membrane for roof waterproofing
Sikalastic®-625 is a 1-part polyurethane, reinforced, cold-applied liquid membrane. It provides a flexible, seamless, low maintenance, durable, smooth waterproof finish. The product is suitable for hot and cold climates.
- Thickness: ~1,50 mm.
- Low maintenance
- Seamless
- 1-Part ready to use
- Cold applied - requires no heat or flame
- Low temperature application > 2 °C
- Easy and quick application by spray, brush or roller
- Economic – provides a cost efficient life cycle extension of failing roofs
- Water vapour permeable
- Retains flexibility at low temperatures
- Moisture triggered technology develops early rain resistance
- Elastic properties – tolerant of thermal movement
- Impact and tear resistant
Usage
- Roof waterproofing for new construction and refurbishment projects
- Waterproofing of flat and pitched roof structures, communal walkways, podium decks and roof terraces
- Waterproofing structures with numerous details such as penetrations, drains, roof lights and complex geometry
- Waterproofing existing substrates of concrete, bituminous felt and coatings, brick, stone, asbestos cement, wood, asphalt etc.
- Only for exterior use
Advantages
- Thickness: ~1,50 mm.
- Low maintenance
- Seamless
- 1-Part ready to use
- Cold applied - requires no heat or flame
- Low temperature application > 2 °C
- Easy and quick application by spray, brush or roller
- Economic – provides a cost efficient life cycle extension of failing roofs
- Water vapour permeable
- Retains flexibility at low temperatures
- Moisture triggered technology develops early rain resistance
- Elastic properties – tolerant of thermal movement
- Impact and tear resistant
Packaging
15 L container
Refer to current price list for packaging variations.
Colour
White (~RAL 9016), Light Grey (~RAL 7035), Cement Grey (~RAL 7042), Pebble Grey (~RAL 7032), Slate Grey (~RAL 7015)
Product Details
APPROVALS / STANDARDS
- CE Marking and Declaration of Performance to ETA 13/0788
- European Technical Assessment ETA 13/0788 based on ETAG 005 Part 1 and 6 - Liquid-applied roof waterproofing using kits based on polyurethane
- External Fire Exposure EN 13501-5:2005, Sikalastic®-625, Exova, Test report No. 328461
- Reaction to Fire EN 13501-5:2007 + A1:2009, Sikalastic®-625, Exova, Classification report No. 328458
- Roof Coverings Exposed to External Fire EN 13501-5:2005 + A1: 2009, Sikalastic®-625, Exova, Classification report No. 323631
Chemical Base
Aliphatic polyurethane
Shelf Life
9 months from date of production
Storage Conditions
The product must be stored in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +0 °C and +25 °C. Always refer to packaging.
Density
| ~1,32 kg/l (at 20 °C) | (EN ISO 2811-1) |
Solid content by weight
| ~78,9 % (+23 °C / 50 % r.h.) | (EN ISO 3251) |
Solid content by volume
| ~70,9 % (+23 °C / 50 % r.h.) | (EN ISO 3251) |
System Structure
Reinforced Roof Waterproofing
Sikalastic®-625 is applied in one coat reinforced with Sika® Reemat Premium and sealed with a final top coat of Sikalastic®-625.
| Layer | Product | Consumption |
| 1. Primer | Refer to substrate pre-treatment | Refer to the primer Product Data Sheet |
| 2. Base coat | Sikalastic®-625 | ~1,0 l/m2 |
| 3. Reinforcement | Sika® Reemat Premium | - |
| 4. Top coat | Sikalastic®-625 | ~1,0 l/m2 |
Consumption depends on the roughness and absorbency of the substrate.
These figures are theoretical and do not allow for any additional material due to surface porosity, surface profile, variations in level or wastage etc.
The build-up in the table corresponds to a reinforced waterproofing kit for flat roof application.
Tensile Strength
| >16 N/mm2 | (ISO 527-1/3) |
Tear Strength
| ~20 N/mm | (ISO 527-1/3) |
Service Temperature
-30 °C min. / +80 °C max.
Chemical Resistance
Resistant to mild acids, alkalis, detergents and some solvents. Contact Sika Technical Services for additional information.
External Fire Performance
| Broof (t1); Broof (t4) | (ENV 1187) |
| Euroclass E | (EN13501-1) |
Dry film thickness
| 1,5 mm | (ETA waterproofing kit) |
Application
Ambient Air Temperature
+2 °C min. / +30 °C max.
Relative Air Humidity
20 % min. / 85 % max.
Dew Point
Beware of condensation.
The substrate and uncured applied product must be at least +3 °C above dew point to reduce the risk of condensation or blooming on the surface of the applied product. Metal surfaces will be more prone to temperature fluctuations occurring and wind chill effects.
Substrate Temperature
+2 °C min. / +30 °C max.
Substrate Moisture Content
≤4 % parts by weight.
Test method: Sika®-Tramex meter
No rising moisture according to ASTM (Polyethylene-sheet).
Pot Life
~1–2 hours
The material in opened containers must be applied before a surface skin occurs.
Times are approximate and will be affected by changing ambient conditions particularly temperature and relative humidity.
Waiting Time / Overcoating
~48 hours
For longer periods up to 14 days, the surface must be reactivated with Sika Reactivation Primer.
Applied Product Ready for Use
| Ambient conditions | Rain resistant | Touch dry | Full cure |
| +2 °C / 50 % r.h. | ~12 hours | ~20 hours | >24 hours |
| +10 °C / 50 % r.h. | ~9 hours | ~15 hours | ~24 hours |
| +20 °C / 50 % r.h. | ~6 hours | ~10 hours | ~18 hours |
| +30 °C / 50 % r.h. | ~4 hours | ~6 hours | ~14 hours |
Times are approximate and will be affected by changing ambient conditions particularly temperature and relative humidity.
SUBSTRATE PREPARATION
General
All dust, loose and friable material must be completely removed from all surfaces before application of the product and associated system products, preferably by vacuum extraction equipment.
To confirm adequate surface preparation and Sikalastic®-625 adhesion, carry out a preliminary trial before full application together with adhesion tests as required.
Concrete and Cementitious substrates
Substrate must be structurally sound, clean, dry and free of all contaminants such as dirt, oil, grease, coatings, laitance, surface treatments and loose friable material.
New concrete should be cured for at least 28 days.
Substrates must be prepared mechanically using suitable substrate preparation equipment to remove cement laitance and achieve an open textured gripping surface profile suitable for the product thickness.
High spots can be removed by grinding.
Weak cementitious substrates must be removed and surface defects such as blow holes and voids must be fully exposed.
Repairs to the substrate, filling of joints, blowholes/voids and surface levelling must be carried out using appropriate products from the Sikafloor®, Sikadur® and Sikagard® range of materials. Products must be cured before applying Sikalastic®-625.
Brick and stone
Thoroughly clean by power wash and allow to dry. Where there is a risk of algal re-growth on absorbent surfaces use Sika Biowash. Refer to the individual Product Data Sheet. Repair any spalling, flaking or other damage and replace any missing jointing.
Asphalt
Thoroughly clean by power wash and allow to dry. All major cracks should be sealed to allow continuity of the Sikalastic®-625 system. Asphalt must be carefully assessed for moisture and/ or air entrapment, grade and surface finish prior to any coating works being carried out. Any priming requirement must also be considered.
Bituminous felt
Felt must be firmly adhered or mechanically fixed. Thoroughly clean by power wash and allow to dry. Treat blisters by star cutting and removing any underlying water. Allow to dry and re-adhere using Decostik® SP. Badly degraded areas should be replaced with Carrier Membrane bonded with Decostik® SP.
Single ply
Various types of single ply sheeting can be coated. Contact Sika Technical Services for additional information.
Bituminous coatings
Bituminous, volatile mastic or old coal tar coatings must be rigid and without a sticky surface. Remove loose, degraded and tacky coatings.
Metals
Ferrous metals must be in a sound surface condition. Surfaces must be clean, free from rust, oil, grease, existing loose or degraded coatings etc.
Prepare surfaces to a bright metal finish using suitable preparation techniques taking into account environmental conditions.
Non-ferrous metals must be in a sound surface condition. Remove any deposits of dust and oxidation and abrade to a bright metal finish. Wire brushing can be used for soft metals such as lead. Surfaces must be clean, free from oil and grease, which, if present, must be removed with a proprietary de-greasing solution. Then wash with detergent, rinse and dry.
Wood
Wood and wood based panel roof decks must be in good structural condition, firmly adhered or mechanically fixed.
Wood based decks require a complete layer of Carrier Membrane SA before the application of the chosen Sikalastic®-625 system. The substrate must then be treated as a felt roof. Small timber protrusions must be flattened by locally planing or sanding to provide a smooth surface.
Paints/Coatings
Remove loose or degraded coatings by suitable preparation techniques to provide a feathered firm adhering edge. Remaining coatings can be overcoated if soundly adhered. Ensure the surface is clean and free from oil, grease etc.
Existing Sikalastic®-625 system
Clean the membrane surface using a power wash at ~14 N/mm2 (2000 psi) including detergent then rinse thoroughly and allow to dry.
MIXING
Sikalastic®-625 is supplied ready for use. Before application, mix for a minimum of 1 minute using mixing paddle and drill or other suitable equipment to mix the liquid and all the coloured pigment until a uniform colour has been achieved. Over mixing must be avoided to minimise air entrainment.
APPLICATION
Strictly follow installation procedures as defined in method statements, application manuals and working instructions which must always be adjusted to the actual site conditions.
General
Always begin application with detailing before installation of the main horizontal surfaces.
Primer
Pour the appropriate mixed primer onto the prepared substrate and apply by brush or appropriate roller. Ensure a continuous, pore free coat covers the substrate. Confirm primer waiting /overcoating time has been achieved before applying successive products. Refer to individual primer Product Data Sheet.
Base coat
Pour mixed Sikalastic®-625 onto prepared substrate the same width as the Sika® Reemat Premium and apply evenly by brush (soft nylon or bristle brush) or roller (short pile mohair roller) at the required consumption rate in 2 directions at right angles to each other. Alternatively spray Sikalastic®-625 with suitable equipment.
Reinforcement
Roll in the Sika® Reemat Premium reinforcement whilst Sikalastic®-625 is still wet ensuring there are no bubbles or creases in the reinforcement. Reinforcement overlaps must be a minimum of 50 mm. Recommendation is to work 1,0 m at a time lengthways applying 1st coat and embedding reinforcement.
Top coat
Pour mixed Sikalastic®-625 onto the applied reinforcement layer and apply evenly by brush or short piled roller at the required consumption rate in 2 directions at right angles to each other. Confirm overcoating times before application. Alternatively spray Sikalastic®-625 with suitable equipment.
Ensure each application / coat is clean and dry before applying next coat.
CLEANING OF TOOLS
Clean all tools and application equipment with cellulose thinners or xylene immediately after use. Hardened material can only be removed mechanically.