hi every one , right have just completed a 4 day course at trades 4 u, just got back from plastering brother in laws bedroom going on top of sound plaster job went ok but one thing walls all pva up first coat of multi finish kept cracking for want of better word , like little tears in it, second coat of pva was tacky/ wet on the corse we were going on top of plasterboard and no prob! advice plse :