We have a stand-up where the shower drain where silicon caulking was used to seal the bottom of the shower to the drainpipe. The house is only just over 2 years and the caulking is peeling back. The the interior pipe measure at 1 3/4" that goes into a slab foundation. We are looking to have it repaired. So it can correctly drain with out issues. Currently we do not feel comfortable using the shower until it is looked at and properly repaired. If you can contact us that would be great.