Should there be a gap in tiled window sill.

[MiketheViking]

I have a bathroom, with a UPVC d/g window, which is tiled from (almost) floor to ceiling and has a tiled window sill. The tiles touch the d/g frame and I am concerned that the coldness of the walls isn't helped by a lack of a thermal? break.

 

My question to the forum is, should there be a gap between the edge of the tiles and the window frame (as I believe that the tiles are bridging the cavity) and if so how large should this be and how would the gap be filled correctly to provide an airtight and insulated sill?

 

Sorry I realise that there is more than one question there. 
 

Thanks in advance

[nod]

No

[mike2016]

I'd prefer a small gap and fill this with a suitable caulk resistant to moisture/mould and that allows a bit of movement but can be stripped back if required and reapplied, otherwise replacement windows would be a messier job down the road. I'm curious myself if this gap is needed or not. 

[MiketheViking]

Thank you nod and mike2016 for your replies, it appears that my thoughts are incorrect. Enjoy the New Year