Adhesive quantities

I intend to get some split face tiles. and have noticed you use Mapei Adhesive - Mapeker Rapid Set Flex 20kg Grey.. what is typical coverage on breeze block and what is typical coverage on plastered painted wall as I need to both inside and out. Then I can order the correct amount of adhesive

The coverage is 4m2 per 20kg bag of adhesive. The website has a clever built in tool which will calculate all of your consumables for you.

You just need to put the stone into your basket first then click on 'consumables required' - The website will then do everything for you