BAUMIT OpenContact Breathable insulation and base coat adhesive 25kg

  • Brand: BAUMIT
  • Product Code: BAOPCO25
  • Delivery date: Up to 10 working days
  • £22.64
  • Ex Tax: £18.87

Description: Breathable, mineral-based, fibre-reinforced, white powder adhesive and plaster undercoat – specially developed for Baumit Open System. Dual purpose contact mortar: as an adhesive for bonding facade insulation boards and a thin layer basecoat (with reinforcingmesh) onto facade insulation boards. 

Product: Factory prepared mineral based, dry powder contact mortar. Suitable for manual and machine application. A system component for the Baumit External Wall Insulation System Open. 

Composition: White cement, organic binders, sands and additives.

Properties: Vapour permeable, high bonding strength, water resistant and good workability

Coverage:   approx. 4-5kg/m2 - as insulation adhesive;

                   approx. 4-5kg/m2 - as base coat;

Substrate: Substrates must be sound, clean, dry, free from frost, dust efflorescence and not hydrophobic. Existing mineral and organic based coatings and paints must be sound and well bonded to the substrate (pull off test and/or cross cut test). The background condition and flatness must be inspected according to the guidance set out in the Baumit EWI Installation Guidelines.


Mixing: Sprinkle the dry powder in to a tub of clean water and mix with an electric hand mixer to a lump free, creamy consistency. Alternatively use a continuous horizontal mixer with a constant water feed. Leave to stand for 5 minutes and remix with the hand mixer. Working time: ca. 1.5 hours. Material which has started setting must not be remixed with water. Mixing with other products (e.g. anti-frost agents or accelerating agents) is not permitted.

Adhesive application: A 50mm wide continuous strip of openContact is applied around the perimeter face of the insulation board and 3 equally spaced hand-sized adhesive dabs through the centre line. The adhesive layer must be 10 -20 mm thick and provide a bonding contact of at least 40%. Deviations in the background flatness of up to +/- 10 mm can be accommodated in the adhesive layer.

Basecoat and reinforcement: After sufficient hardening of the adhesive layer the insulation boards can be sanded down and the dust removed. Baumit openContact is applied to the boards with a stainless steel notched trowel (10 mm notches). Continuous sheets of openTex reinforcing mesh are placed onto the openContact, free of creases and with 100 mm overlapping edges. A further 1-2mm of openContact is applied wet on wet over the embedded openTex reinforcing mesh. The openTex reinforcing mesh must be covered with at least 1 mm (0.5 – 3 mm max. at the overlapping edges) of openContact. Excessive trowelling is to be avoided. Trowel lines are to be removed after hardening. The overall basecoat thickness must be from 3 – 6 mm.  

On account of its good adhesive properties, Baumit OpenContact can be used for gluing (or smoothing) XPS insulating panels. N.B. in this case the high water vapour permeability of the material no longer applies.

Generally speaking, the Baumit OpenContact system is used for thermal insulation anywhere where a thermal insulation system with a high level of water vapour permeability is required, and thus also for the thermal insulation of porous concrete block walls

Thanks to the white putty, you can easily check whether Baumit OpenContact was actually used on your façade!


Thumb File information
Technical data sheet/baumit_openContact.pdf 107.75KB 368
Product Info
Weight 25kg
Colour white
Coverage 5m2