In general, this will be determined by the purpose and application of the mortar. We would expect appropriate preparation in accordance with best practice; where the surface is clean, free of dust and
Where necessary the background should be adequately dampened to promote adhesion/bond with the host surface. Dense impervious backgrounds/materials are unlikely to be very absorbent and require little to no dampening, whereas more absorbent backgrounds/materials require adequate dampening in order to prevent rapid drying. Whilst Cornerstone Insulating Render includes additions to try and mitigate these issues, best practice still needs to be followed.
A bag of Cornerstone Insulating Render will require 4 to 5 litres of clean potable water. The water addition will vary according to the application and desired consistency/workability of the mortar. Always avoid making the mortar too wet, as this can promote shrinkage issues, especially when used as a render.
For drum type mixers, it is essential not to overfill the mixer. As a dry mixed material, it is possible that some settlement or separation may occur in the bag during transit; when mixing part bags, it is especially important that the dry contents are thoroughly blended prior to mixing with water.
Best Practice/Advised Mixing - First add 60 to 70% water of the total water into the mixer, followed by the Cornerstone Insulating Render and turn the mixer on. Allow the mortar to mix until the water is thoroughly distributed, then add additional water to achieve desired consistency.
Mix for a minimum of 5 minutes.
Other mix methods - We accept that it is generally site practice to add the water to the mortar, providing the mortar is well mixed and not too wet, this method will be sufficient.
Quenching - Like most lime mortars Cornerstone Insulating Render will benefit from Quenching; allow the mortar to stand for 10 to 20 minutes after mixing, before use.
Should additional water be needed after quenching to maintain workability, this can be added and mixed thoroughly through the mortar.
Once water has been added, Cornerstone Insulating Render has an open time of at least 18 hours.
Each project is unique, always seek professional advice before undertaking a project.