So I have two lines on the brick in front of me. Top line is the datum for the patio finished level. Bottom line is 30mm down line for the drainage lo w point. I am putting in a bottle gully which has about 40mm height adjustm ent on the grating. Can I decide what level to set the gully before it is c oncreted in ? Of course not ! Spinning in my head: I might want to set the grating up to 20mm below the s urrounding slabs (but probably would be 5 to 10mm). But then what if for so me unknown reason the drainage low point needs to be be higher than I expec t - will I have enough adjustment upwards?, etc. etc. So I keep playing with it - up a bit, down a bit, that will do, and so on. OK, I'll leave it for now, concrete it in on the bank holiday ..
Is this behaviour normal, or am I heading for some type of DIY nervous brea kdown ?
Simon.