1/2" hardibacker up to solid surface shower pan

Shower pan: solid surface
Walls: moisture barrier lining under 1/2" backer and will be tiled

Question: So, the shower pan mfg suggested that the backer installs up to the small ledge of the pan which is about 1/4" thick and 1 1/2" high. He mentioned it will not fit flush and the backer board will protrude out leaving about 1/4" delta from the surface of the pan lip and the surface of the backer board. He also mentioned that when tiling, the tile will then come all the down way down to the top surface of the pan, even thought there will be 1 1/2" of dead space due to the shower lip and backer board mismatch as I stated above. Assuming this approach is correct, I had planned on adding silicone where the two come together to make sure it's sealed. Does all this sound correct for this type of install? I'm not comfortable with the 1 1/2" of dead space. Thanks.

1.) You can notch the backside of the backerboard so it will lap-over the lip. Then seal that lap. Don't forget to lap your moisture barrier over that lip and seal it also.

2.) You can stop the backerboard at the top of the lip allowing the moisture barrier to lap over the lip and seal those junctures. THEN fill the worrisome gap with thinset as you install the tile all the way down to the top of the ledge.

You are planning to use thinset? Correct?

Don't know that I have ever seen one of those lips as tall as 1-1/2 inches.

1 1/8" to be exact Over estimated a bit. Those are great suggestions. Thanks for the input. Oh, and yes on the thinset.