If the shower or bath have been installed without a Classi seal or Aqua strap etc why not install a Sealux pack and then overlap the part thats against the wall with tanking tape and then tank the walls as usual. We've done this in hundreds of houses, its not as good looking as using a Classi seal but it's bullet proof if installed correctly.
I always use Classi seal or a Sealux pack in conjunction with tanking tape and paste. Silicon the Classi seal to the wall, overlap that joint with a tanking tape right round in one strip, then put on your vertical strips, paste over the whole lot, it can't fail if done correctly.
Sealux have some good installation videos on they're website, but they don't show it as part one of the two part system I've suggested[/QUOT
Hi
@LEE MAC, do have a link to these seallux kits, Thanks D