Beyem Fir Yeso

Enhanced cement based tile adhesive for interior use on plaster substrates

BEYEM FIR YESO is an enhanced cement based tile adhesive, formulated with white cement, selected aggregates and  special additives to improve workability and adhesion. No vertical slip. Allows adjustment  of tiles. BEYEM FIR YESO  is formulated with special additives that prevent the formation of expansive salts by reaction of calcium sulfate of  gypsum substrates  with cement.

  • Great plasticity
  • High water retentivity. Highly  thixotropic.
  • High  tensile adhesion strength and mechanical  strength.
  • Long open time. Allows adjustement of tiles.
  • No vertical slip.

Laying of ceramic tiles of medium/high absorption on plaster substrates in interior walls and floors. Especially suitable for laying ceramic tiles of small and medium format  and IIb / III group. 

BEYEM FIR YESO is suitable for:

  • Projected plaster, plaster boards, and plaster panels.
  • Gypsum based substrates.
  • Cement  based substrates.
  • Cement based renders /plasters and screeds.
  • Concrete floors.

Substrates must be clean, compact and  free of substances that reduce adhesion such as dust, oil, grease and with no loose material. Uneven areas must be corrected with suitable smoothing and finishing products. Substrates must be free from any rising damp and have already completed the curing period of hygrometric shrinkage. Dampen substrates with water  to cool down if they should be too warm, in case of wind or over absorbent substrates  and wait until the thin layer of water disappears. Do not  use on paint. 

Mix manually of mechanically BEYEM FIR YESO with 5,75-6,75 l per bag of clean water until a homogeneous, creamy and lump-free paste  is obtained. Let the mix stand for 5 minutes before application.

Small tiles must be fixed using  a notched trowel of 6×6 mm. For tiles sizes greater than 400 cm2,  a notched trowel  8×8 mm  must be used.  Spread the mixed product onto the substrate to a maximum surface area of 1 m2 or no more than can be tiled within 20/30 minutes in normal conditions. Unfavorable environmental conditions (strong sunlight, drying wind, high temperature as well as a highly absorbent substrate), could drastically reduce this time to a few minutes. Bed the tiles firmly into the adhesive with a slight sliding and/or twisting action, to ensure a good contact and complete coverage.

It is good practice to lift an occasional tile after fixing, to verify that the required contact is being achieved. Back of the tile must be completely wet.

  • Gypsum substrates must be completely dry and with no loose material.
  • Do not apply on slaked plaster or plaster with a thin coat of final plaster work.
  • Do not apply on plastic, metal or wood.
  • Do not apply below 5ºC or above 30ºC.
  • Do not apply when there is  risk of frost, rain, strong wind or direct sunlight.
  • Leave joints between tiles with a minimum width of 2 mm. Grout with  BEYEM JUNTA UNIVERSAL / BEYEM JUNTA EXTRAFINA.
  • On floors  with a surface area greater than 30 m2 , it is recommended to leave separation or sealing joints filled with a deformable material.
  • On interior floorings larger than 15 m2, it is advisable to keep a free perimeter expansion joint between the floor and the wall or pillar, hidden by a skirting board (of approximately 5 mm). 

Product identity. Properties of mixture and application data





Bulk density

≈ 1340 Kg/m3

Density of the mix

≈ 1630 Kg/m3


0-600 µm

Mixing water,% 

± 25%

Pot life

≈ 2 h

Adjustability time

≥ 20 min


≈ 24 h


≥ 3 Kg/m2 

Tariff code


Final performances



Annex ZA EN 12004-1

Initial tensile adhesion strength

≥ 0,5 N/mm2

Tensile adhesion strength after water immersion

≥ 0,5 N/mm2 

BEYEM FIR YESO is packed 25 kg plastic lined paper bags.

Storage:  when stored unopened in a cool dry place, shelf life is 12 months from date of manufacture.

Tools can be cleaned easily with water  before the product hardens. Hardened product can be remove only mechanically.

Laying of ceramic tiles on plaster/gypsum substrates must be carried out with cement based adhesive compliant with EN 12004-1 – Annex ZA, such as Beyem Fir Yeso manufactured by Rodacal Beyem company. The substrate must be compact, free from any flaky, loose parts and must be clean and cured, having already completed the shrinkage stage. Existing joints must be respected and elastic fractionizing and perimeter joints must be created. Ceramic tiles must be laid with joint-gap spacers with a width of ___ mm. 

For further and complete information about the safe use of our product please refer to our latest version of the Safety Data Sheet, which is available upon request.

Disposal of the product and packaging must be in accordance with current legislation. This is  responsibility of the final product user.


Technical sheet

Component Safety Data Sheet

Declaration of benefits

Factory Production Control Certificate

Certificado Sistema Gestión de Calidad ISO 9001

Certificado Sistema Gestión de la I+D+i UNE 166002


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