7 | GEOCOLL® ADHESIVE and SKIM COAT BASED on NATURAL HYDRAULIC LIME

7 | GEOCOLL® ADHESIVE and SKIM COAT BASED on NATURAL HYDRAULIC LIME

Despite the fact that there are good quality adhesives on the market, Geopietra® manufactured stone veneer requires very special characteristics that cannot be fully met with any of those available, most of which have been developed for use with ceramics (EN12004). However, Geocoll® has been produced in accordance with EN998 and has been specially optimised to improve the performance and duration of installations on any base or external thermal insulation. Geocoll® contains natural hydraulic lime, giving the product features such as improved flow characteristics, zero vertical slump, breathability and good mechanical properties. It is practical to use and facilitates the work of installers by dealing with issues that have transpired over the years when carrying out installations on site. Along with Georete fibreglass mesh, Geocoll® is also the ideal product for applying reinforcement solutions to unstable bases (see section 5) or support reinforcement for external thermal insulation.

COLOUR for dry-stacking installations

With a dry-stacking installation of dark models, the use of light-coloured adhesive will be obvious between joints, giving an uneven effect of depth. To avoid this, Geopietra has created a new powder dye to be mixed in measured amounts into a bag of Geocoll, which is available in 2 colours: BLACK, suitable for all situations and BROWN, ideal for colors BR Real White and LIONE.
Working with a coloured adhesive makes it easier to cover cracks and profiles in the stone during installation. Furthermore, subsequent grouting with the Geobi mortar is quicker and more accurate in the larger joints, maintaining detail which is essential for making the wall look authentic.


PREPARATION

Mix a 25-kg bag of Geocoll® with 7.0 L (adhesive) or 7.5 L (skim coat) of clean water using a mechanical stirrer till a smooth paste with no lumps is obtained. Let it stand for 10 minutes then mix again briefly. The consistency of the paste can be adjusted by adding small amounts of water. The adhesive is applied using a ‘wet-on-wet’ technique i.e. Geocoll® is spread over the back of the stone with a trowel (without teeth) and a thin layer must be applied to the installation base. The stone should then be pressed onto the wall using slight sideways movements from left to right until excess adhesive can no longer be pressed out (suction effect). If the stone slips downwards use Geocoll® with a thicker consistency. Position the stone accurately and uniformly, remembering that after approximately 15 minutes the stone can no longer be moved or removed. Highly absorbent bases can be dampened beforehand, ensuring there is no film of water when gluing the stone.

NOTE

Operating temperature +5°C to +35°C ambient. Do not install with base temperatures lower than +5°C or greater than +25°C. With very hot ambient temperatures check that the wall does not exceed critical values for the adhesive (water evaporating too quickly in the adhesive blocks the chemical gripping action). If this is the case cool the base by wetting the surface with plenty water, and the back of the stone itself if necessary. Geopietra® should then be installed when there is no film of water. Protect from rain, do not apply to frozen or thawing bases, suspend installation with temperatures close to zero or if there is a risk of frost in the next 24 hours. If there is the possibility that temperatures may fall significantly at night cover the completed work with glass wool. Do not use hardened material. Do not add water to restore workability. Do not add other materials which are not included in the product information leaflet. Comply with any structural joints.