hi there, please could someone tell me difference with rendering and skimming internal walls. The reason I ask is that on internet, render seems to be for external walls ie breeze blocks. My problem is that I have a bathroom which after taking tiles off revealed, parts of plaster, parts render meaning some concrete spread onto breeze blocks and even some breeze blocks with nothing on them, these are our internal walls which is cavity wall, so block breeze inside then cavity then brick, what do I do to make wall sound for tiling in bathroom with all these different surfaces and I don't wish to plaster as it takes ages to dry, would like to tile pretty soon as only bath in house and 6 peope! 
Is there a fast covering for walls? and what is it called render or skimming?? Thanks, I may learn something new.
Is there a fast covering for walls? and what is it called render or skimming?? Thanks, I may learn something new.