just wanting to know if using building sand with lime would binde well enough on a render sand scrach coat, the reason for the building sand as a float coat is that the i feel that the local rendering sand is a bit too corse for a smooth render finish anyones thoughts on this one pls lads oh and i know i don't need a retarder in my scrach coat but would it affect the suction rate on my float coat or is just on the strach setting cause the lime will give enough re***d in the float as it is, i got a 3in1 on the cheap thats why i ask :-\