Application of single-layer mortar on aerated concrete

SolutionApplication of single-layer mortar on aerated concrete

System description

Aerated concrete block is a lightweight construction material intended for both individual and collective housing. As it is a substrate with very particular characteristics, it requires a series of precautions to be taken when applying a single-layer coating.

It is a solid material, with low density, low unit weight and excellent thermal insulation capacity.

Its high porosity can lead to dehydration or rapid absorption of the mixing water of the single-layer mortar.

As a consequence, the correct development of the mechanical performance of the coating is prevented.

As a consequence, the correct development of the mechanical performance of the coating is prevented.

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Solution

PREPARATION OF THE SUBSTRATE

Apply a primer made with PROPAM® LATEX (diluted with water) or PROPAM® PRIMER SOL (undiluted) on the substrate to prevent it from rapidly absorbing the water of the single-coat mortar.

  1. Primer with PROPAM® LATEX: Dilute 1 volume of PROPAM® LATEX with 4 volumes of water, stir until a homogeneous mixture is obtained and apply to the substrate with a brush or roller.
  2. Primer with PROPAM® PRIMER SOL: Apply this primer directly to the substrate by brush or roller (no thinning required).

APPLICATION

Use REVAT® SUPRA, REVAT® RASPADO or REVAT® PIEDRA, single coat mortars with a low modulus of elasticity.

Knead the single-coat mortar and then apply it manually with a trowel or spraying machine on top of the previous primer (still fresh).

Carry out the planned finish.

Recommendations

  • It is not advisable to apply monocoats in dark colours, particularly on façades that, due to their orientation and geographical location of the work, are very exposed to the sun. In these cases, due to the low heat dissipation offered by the cellular concrete substrate (due to its high thermal insulation performance), shrinkage cracks may occur due to the accumulation of heat in the mortar.
  • To minimise the stresses caused by thermal expansion, it is advisable to apply glass fibre mesh centred on the thickness of the cladding.
  • LayREVAT® 110fibreglass mesh at the joints of the blocks with other materials (pillars, slabs, lintels, etc.).
  • Another accepted option prior to the application of a single coat is the FLEXIBLE SYSTEM: PROPAM RENOVATION ANTI-CRACKING without the need for prior primers.