RENDER BASE COAT

  1.  Product description

Mineral dry bagged render base coat based on Hydraulic Lime binders and aggregates (Product designation MMRBC)

  1. General application and uses

MMRBC is especially suitable on dense impervious masonry as an undercoat for the Façade 400 where a single coat application is not suitable and for the majority of MM Ltd dry bagged render straightening and finishing products. It is especially suited to difficult or low suction backgrounds. It has good vapour permeability for render to some mass masonry wall construction such as bridge parapets, cutwater masonry, below ground masonry chimneys and the like in high exposure areas. It may also be used as a first coat on expanded metal lath.

Suitable for dense impervious natural stone, cast or fired masonry as a Base Coat Straightening Coat and a Finishing Coat, where a very robust render is essential (Marine Works)

  1. Material Properties

See typical Mortar Performance chart for physical properties for the range of Masons Mortar Ltd ready mixed Lime mortars

  1. Application Instructions

Ambient and materials / surface temperature range to be within 30C – 300C – out with these ranges consult our technical department. Use control methods to maintain ambient conditions until mortar is sufficiently cured

  1. Background preparation.
  • Remove, cut out defective mortar.
  • Clean away all loose and friable materials, remove dust and any biological growth.
  • Dampen existing mortar, no standing water on masonry, remove surface water with air or dry sponge / cloth or brush.
  • All construction materials should be stored clean, and dry, off the ground or on tarpaulins to prevent contamination from potential salt bearing soils and water
  • All backgrounds must be free of salts, dust, loose or friable materials
  • Power wash if required to remove soiling or vegetation. Use biocide treatments as required
  • Backgrounds to be rendered should clean, stable and be re-pointed prior to the application of Render Base Coat.
  • Never work with frozen or saturated masonry or masonry backgrounds
  1. Rendering
  • MMRBC is an ideal base coat materials for render on many mass masonry wall constructions, suitable for low permeability natural stone and fired clay or dense cast masonry in difficult or exposed locations such as one face of an exposed parapet, sea walls, cutwater and inside parapets of masonry bridges, and all dense or impervious masonry in new construction.
  • Spray, cast or trowel on to a well prepared background and allow a minimum of 1 full day of curing per mm of thickness before applying further coats.
  • Second coats and finishing coats in a variety of materials, such as Façade 400, Thermocromex
  • Proper protection must be maintained throughout the curing process, After placing keep work protected from strong sunlight, drying winds, rain and frost until properly cured.

 

  1. Mixing
  • Allow Approx*4 litres of clean potable water per bag depending on use. *Water content is a function of use and should be adjusted by the applicator to suit the conditions and operation being carried out.
  • For small quantities use hand held drill or whisk type mixer. Mix dry powder into water gradually, start wet, work to drier consistency
  • For larger mixes pan mixers, paddle mixers are best.
  • Do not short mix, short mixing requires greater water content and will lead to bleed or shrinkage. Over mixing can result in weaker mortar. Mix for 3-4 minutes with drill and whisk mixers. In free fall (Rotating Drum) mixers, mix 5-6 minutes. If hand mixing (small repairs), mix only small amounts and ensure the materials are fully mixed.

 

  1. Metal Lath Backgrounds
  • On well fixed metal lath backgrounds, ensure adequate laps and an even thickness across the lath with all the lath fully covered (including laps) by at least 10mm of MMRBC
  1. Consumption
  • 1 25 KG Bag of Masons Mortar MMH80KA30C will build approx 50 standard metric bricks with 10mm joints or Re-point 7.5 M 2 at 10mm x 10mm1 25 KG Bag of MMRBC and will cover 1.5M2 of render at 10MM thick
  1. Clean up
  • Wash tools with clean water immediately after use
  • Please dispose of all packaging thoughtfully

Hazardous substances classification

  • R 38: Irritating to the skin
  • R 41: Risk of serious damage to the eyes
  • S 2: Keep out of reach of children
  • S22: Do not breathe dust
  • S24/25: Avoid contact with skin and eyes
  • S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
  • S37/39: Wear suitable gloves and eye / face protection
  • S46: If swallowed, seek medical advice immediately and show this container or label

Transport Hazard Class

N/A

Disposal

EC waste code no 170101

Any residue must be emptied out of bags or containers before recycling.

Solidify any residual material with water and after consulting the relevant authorities, dispose of in a construction material land fill site.

Performance

Compressive strength 72 hours N/mm2 1.5
Compressive strength 7 days N/mm2 4
28 days 8 -10
Elasticity Modulus MPa 7-9000
Vapour Permeability g.m2.hour.mmHg 0.75
Capillarity g.m2.min-1/2
 W2
Mortar Performance data provided from Laboratory standard testing regimes. Site mixed and placed mortar performance may vary depending on curing conditions.

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