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AK 531 White thermal insulation adhesive

For bonding EPS and mineral wool insulation boards and embedding reinforcing mesh in ALPOL EKO PLUS PREMIUM, ALPOL EKO PLUS WM and ALPOL TERMO BIS thermal jointless insulation systems. Recommended for use under light decorative plaster. Intended for interior and exterior use.


Substrate type
Cement, cement-lime and lime plasters. Walls made of bricks and ceramic blocks, silicate and cellular concrete blocks and others, concrete substrates, mineral wool or Styrofoam layer in thermal insulation systems.

Substrate preparation
For bonding thermal insulation boards
Substrate should be clean, dry, stable and sound. New plaster work and concrete should be set and seasoned. Remove loose, cracked and brittle plasters and widen joints. Patch slightly chipped areas with ALPOL AZ 130 quick setting or ALPOL AZ 135 levelling mortar, apply ALPOL AT 310 plaster on larger surfaces. Remove contamination and peeling paint from sound plasterwork. Dedust the surfaces. Treat the loose substrate with ALPOL AG 700 and ALPOL AG 703 deep penetrating primer to reduce absorption, if necessary.
For embedding mesh
The thermal insulation surface should be clean, dry, stable and sound. Any gaps between boards should be filled with insulation material strips cut to size. Grind the Styrofoam surface with a metal grater or a hand sander. Spread thin layer of adhesive on the mineral wool board surface and allow time until it initially sets.

Instructions for use
Stir the bag contents manually or mechanically with specified amount of cold and fresh water to reach a homogeneous and required consistency. Allow 5 minutes and stir the prepared mix again. Use the adhesive within 1 hour from mixing with water. If the adhesive thickens in that period of time, stir it thoroughly without adding water. Adding too much water impairs all characteristics: adhesion, tensile strength and setting time. Spread a thin layer of the adhesive on the mineral wool board, rubbing it into the board surface before bonding.

Bonding insulation boards:
With the use of a trowel, the adhesive can be applied on the insulation boards “in spots” and all around the edges, bearing in mind that it should cover at least 60% of the board surface after pressing it against the wall. The adhesive can also be spread all over the board surface with a notched trowel. If wool lamellas are used, apply the adhesive all over their surface. Press the insulation boards slightly against the wall. Board position can be adjusted within 10 minutes after bonding. Bond the boards within max. 20 minutes from spreading adhesive on the substrate. Fixing with the use of mechanical fasteners can be performed after at least 1 day, whereas the mesh can be embedded after 3 days after bonding the boards.

Embedding mesh:
Apply the adhesive with a trowel onto bonded boards and spread it with a notched trowel. Then, apply the mesh and press it with a plain side of the float into the adhesive layer so that the mesh is no longer visible. Apply another adhesive coat if necessary. Once the adhesive dries, any possible surface irregularities should be patched again or ground with sand paper. After the adhesive is fully dry (minimum 2 days), appropriate ALPOL plaster primer can be applied. The decorative plaster can be applied no sooner than 3 days after embedding the mesh in adhesive.

Mixer or low-speed electric drill, basket mixer, notched trowel, plain float, trowel, container for the adhesive.

Working conditions
Work in ambient temperatures between +5°C and +30°C. Do not add any other agents to the adhesive. Protect freshly applied adhesive work from excessive drying and moisture.

Store in original, unopened packages in dry place – shelf life 12 months from production date. Protect from moisture during transport and storage.

The specifications and instructions for use are given for the temperature of (20±2)°C and relative air humidity of (60±5)%. The workability may alter in different conditions. Becomes alkaline after mixing with water. Irritating to eyes and respiratory system. Appropriate eye, respiratory system and skin protection measures should be used. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. Keep away from children. Use water to remove fresh dirt or ALPOL AI 770 cleaner to remove hardened dirt. The manufacturer accepts no responsibility for damage caused by unskilful or inappropriate use of the product.

General recommendations
Always follow good building practices, observing health & safety standards and regulations. Refer to the application manuals for ALPOL insulation systems, ITB instructions or indications provided in this data sheet for details on bonding insulation boards and insulating walls.

Composition: blend of cement and sand as well as mineral admixtures, additives and fibres
Bulk density approx. 1.5 kg/dm³
Appropriate amount of water between 5 and 6 litres per 25 kg of dry mix
Adhesive workability 20 min. after application of adhesive on the substrate
Workability approx. 1.5 hour from mixing with water
Adhesion to concrete ≥ 0.25 MPa
Adhesion to EPS boards ≥ 0.08 MPa
Adhesion to mineral wool ≥ 0.08 MPa or damage in the mineral wool
Yield approx. 19 dm³ from 25 kg
Coverage while bonding boards between 3 and 5.5 kg/m²
Coverage while embedding mesh between 3.5 and 6 kg/m²


For bonding EPS and mineral wool insulation boards and embedding reinforcing mesh in ALPOL EKO PLUS PREMIUM, ALPOL EKO PLUS WM and ALPOL TERMO BIS thermal jointless insulation systems. Recommended for use under light decorative plaster. Intended for interior and exterior use.

Additional information

Weight 25 kg