History:
Ive been doing plastering and rendering for 8years in total its a very good tight buissness family run we treat all the work the same not rushed always make sure the customer is happy by the end of the job we also make sure everything is above board so the customer can rely on us with no problems
Answers:
First the best way to take on a artex ceiling is plenty of pva and use a thistle bonding its much thicker let it go off preferablly 24hours then come back and put your finish coat on (multifinish). also you couldnt put a third coat on its to much weight best way to do it is either strip the ceiling or overboard it with new plasterboard
You should fill it in with new plasterboard and then multifinish
First off you went wrong with using sharp sand for rending also using sand and cement over paint work it doesnt stick and just becomes blown render the best way to tackle something like is give it a key if its solid or if blown take the blown render off if not use a splits mix which is 1 soft wash sand and 1 cement paste it on and gives it a good solid key to render over the top
Pva the wall first use soft wash sand and cement no lime because lime is only used to stop the sand and cement from going off so quick its a retardent has to be nice fluffy mix aswell
Its all depending on how you use the multi finsih which additives you use and plus the cold weather plays a massive part in it