Sealing gap between top of bath and bottam row of wall tiles.

sonny liston

Hi folks,
there is a 1mm to 4mm gap between top of my bath and bottam row of wall tiles. The builder initially filled this gap with grout, and then a layer of silicone.
I have removed both the grout and silicone as they had gone mouldy.
I am reading mixed reviews about whether I should (a)fill the gap again with grout and then cover with silicone, or (b)just use the silicone by itself to fill the gap. Any advice?
I also have some blue masking tape which I intend to use to get a clean finish when applying the silicone to the bath/tiles. But I'm afraid this will leave a lip in the silicone when I remove the masking tape, that water may eventually penetrate? I suppose most pros on here don't need the masking tape to get a clean finish. But for novices, is it advisable or a bad idea to use the tape?
Thanks.

Calahonda52

Use Tech 7, forget about tape, smooth it with your finger, Rolls Royce, lifetime job. what colour are bath/tiles

hognef

Definitely don't use grout. Many do, but really you need a flexible sealant to fill a joint that will move. Any grout will crack with any movement at all.

Use a mould resistant, sanitary, silicone, which is made specifically for bathroom use, rather than the generic, one-size-fits-all, Tec7 suggested above.

For smoothing, first dip your finger in a mix of washing up liquid and water.

sonny liston

Thanks for the replies.
I already have Dow Corning 785. I will use that to fill/seal the gap.
Cheers!