tiling first time help around shower tray

[pritsuk2002]

i have a rectangular shower tray that sits in the corner of the bathroom. it is fitted so that 2 sides of the tray are againt a wall (actually sits undeath it) ,one side has a small stud wall against it which had plasterboard attched with tiles on top and the other side is the side you would enter and has sliding doors. the problem is on the 2 sides where the tray is under the wall the plaster does not meet the tray there is a gap in some areas. will this cause a problem?? its on the bottom of the wall meeting the tray. i ithink its been damaged when prevous person had it the grout failed and water seeped in through one spot and made its way down and damaged the lower area around the shower tray. when i ripped the tiles off i noticed areas of darker plaster(obvuously water damaged ) this i noticed was all around the wall and stud wall where it meets the tray. or cud it be the silcone failed but mostly i relaease it had got through one tile and must have made it way around and down. im not sure if the silicone failed or if the grourt failed or maybe both. would the gap between the show tray and wall need to be patched or am i ok??i left the dark plaster to dry and rubbed off once dry it looks ok now. but regards the gap should i be concerned?? if it needs filling what should i use???

 

[gcol]

If the tray has an upstand (a raised lip) on the sides that fit into the wall then you need do nothing. If the tray edge is just flat then I'd be inclined to run a bead of silicone in the gap so that should your eventual silicone seal between tiles and tray fail, the bead of silicone would provide a barrier to the water.