I made that same mistake myself and if you read the temps on the tin it doesnt do for our high summer temps and then it lifts and bubbles in the heat and leaks in winter or during the rainfall.
But you need to clean away the damaged area first and then paint it with red, grey , green or white SEKA. Can get it from Mayors or Ive bought the grey and the white one from Paviementos in Jesus next to Clibegas.

However,if you have a crack you would be better advised to buy a small bag of waterproof concrete before you paint over it.

Going forward it is best too recover the whole flat roof with waterproof concrete and then tile it using pool tile adhesive.

Have fun with flat roofs . I have encountered every pain possible with roof issues over the last few years.

Good luck.

I haven´t bought any this year but it is a big can and I think it was around 80 euros last time and it covers a fair bit. (amd myself as well!) Will try and find out for you.

Hola all,
          Not been out for a while and our neighbour checked the casita for us and discovered that there is a major leak on a small patch of tiled foor but enough to cause the collapse of some plasterboard from the ceiling inside - do I need to replace the tiles and then seal up with w/proof concrete and w/proof paint or is there any other way around this.
                     Thanks,
                               Brian.