i have removed the old tiles and want to put up new tiles
do i have to scrape off whats left of old adhesive or can i tile over it?

What is behind the adhesive??? Plaster or plaster board?

plaster

Bucket of hot water and a brush. Brush water onto adhesive and leave for 20 minutes or so. This will soften the adhesive and then you will be able to scrape it off with a decent scraper. You may need to brush on a couple of times.

If you haven't got one, buy a long handled scraper that takes what looks like an over sized Stanley blade. Once adhesive has softened enough it will scrape off like butter, only not yellow.

That will work if its dispersion adhesive (ready mixed) but not if its cement based. A good scraper and plenty of elbow grease is what you need.

My money was on tubbed addy being on the walls.................might just be luck, but I have never taken tiles off the wall to reveal cement based addy.

well the sister went and tiled over the old adhesive

so its like a moto cross track! grouted and all
so theres a 11mm gap between bottom line of tile and worktop one end
and 2mm the other end!... so goin to silicone the gap as i'm told that grout would just crack
with movment in a wooden worktop
so the question is which silicone?

dow corning

I would have thought the differing gap is due to the worktop or tiling or both being out of level. The gap at the junction of worktop and tiles should always be siliconed as its a movement joint. Even if the worktop is granite. If white, I use Dow Corning 785 sanitary silicone, Mapei if I want a coloured one.

differing thickness in the pieces of cardboard to protect the worktop while tiling/grouting

the cheek a ya... the wortop is level

scrape it off. Tiling is hard enough as it is, try make the task as painless as you can.

With a difference in tile / worktop join like that I'd cover it with a length of upvc quadrant / beading.
And 11mm silicone bead will not look good for long - even if you use Dow Corning.

Nice bit of quad will hide the gap nicely.

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