Waterproofer / plasticiser


New Member
Long time lurker, first time poster.
Getting ready to have my first sand/cement render attempt (DIY) - I’ve got so much useful info from you all but have one final stupid question I can’t seem to get an answer to.

My waterproofer and plasticiser both state quantities based on the amount of cement used - eg per 25kg bag - is this as simple as it sounds, or is is per 25kg of mixed render/mortar?

Can’t quite Wrap my head around The fact a mix with more sand would therefore mean less waterproofer in the bucket overall that a much more cement based mix - stupid question, sorry!


Well-Known Member
Are you a CBeebies presenter or just gay


Well-Known Member
Ahh, that’s my point though - so if it’s say 90ml per 25kg cement, is it 90ml per 25kg of cement/sand mix, or per 25kg of actual bagged cement?

90ml would be to a 25kg quantity of dust

So a mix like 75kg of sand to 25kg cement make sure there is 90ml to this 100kg batch