Grouting deep but narrow gap between tiles

[mikelouw]

Hello All. New to this forum and to tiling....so please be kind if this is a really dumb question....

I've just retiled an area of my bathroom (tiles on wood pod in apartment bathroom). I'm left with a gap between two adjacent areas of tile, which is not so wide (5mm) but is quite deep (about 1 cm, a bit more in places). Should I fill the gap entirely with grout, or should I first half fill it with something else (tile adhesive, some kind of sealant?) and then finish off with grout?

Thanks!

Mike

[warmadmax]

picture would help advise,

is it supposed to be a removable section? if so finish in silicone round the edges

[mikelouw]

picture would help advise,

is it supposed to be a removable section? if so finish in silicone round the edges

Thanks for the quick reply, warmadmax. No, it's not a removable section.

I've attached two pictures; one of the overall job and one a detail of the gap in question. Background story: due to damage I had to replace a section of the tiling, Needless to say, I couldn't find any tiles that anywhere near matched the original ones, so I decided to make a "feature" of the replaced tiles by using a black stainless steel mosaic tile. This has led to the replaced area being somewhat recessed, and due to tile size differences has left a large-ish gap.

I don't mind this, but it's left me with a gap which is a bit wider than I originally said (7mm), and about 8 mm deep. The depth of the original tile+adhesive is 8mm (top of detail picture), and the depth of the new mosaic tiles+adhesive is about 5mm (bottom of detail picture). So I have this gap to fill, but I also need to fill it at a slope from top to bottom (8mm at top, and 5mm at bottom of the gap). I'm wondering how best to do this, bearing in mind waterproofing is paramount! I hope this makes sense...

Thanks and best regards, Mike.

[royaloakcarpentry]

Looks like white grout to me..........grout the new are of mosaic and then run around the perimeter in white silicone. You need Dow Corning 785.

You would normally be able to get a repair, like that, flush and then grout to finish. I wouldn't trust just grouting the whole area though on that repair. Especially as it looks to be at a shower end of the bath.

[mikelouw]

Thanks royaloak! Any alternatives to Dow Corning 785 (in case it's not available here in Ireland)? Would UniBond Bathroom and Kitchen Anti-Mould sealant be OK? It's silicone which needs to be cleaned up with white spirit i.e. not water-"soluble".
I agree it would've been nice to get the new mosaic flush, but that would've involved a very thick adhesive bed which would have extruded through the gaps between the mosaics, making cleaning a real PITA, as I intend to use black grout.
I'm a complete newbie at this so need to improvise......

[royaloakcarpentry]

You will get Dow Corning over there. Unibond is useless. Good plumbers merchant will stock Dow Corning or a good builders merchant.

Ways to get mosaic flush are.......... Build out area with cement based adhesive then tile mosaic as normal once it has set. Tile area of mosaic with cheap thin contract tiles and then mosaic on top of them.

In your scenario, pack the board off of the studwork and fix mosaic as normal.

You are correct in that using a thick bed will not work in most cases. It does if you use spacers between each mosaic, press onto adhesive lightly and pin to stop them slumping. Although the spacers depend on how well the mosaic are spaced on the sheet....tops tiles, you have absolutely no chance of doing it.