It's time to vent the crawl space and have done the appropriate info gathering from the governmental sites and have a couple of questions that I don't find addressed in those sites (which I can't believe since they seem like pretty basic requirements for this). I am to lay what essentially amounts to 'crusher run' rock on the floor first (I have seen several numbers listed so there must be a veeeery loose standard for aggregate sizing). 1) Is three inches about right? 2) Can I place the perf'ed pipe right on top and then drape with 6 mil poly or would a shallow trench be appropriate (suggested by my mason). 3) The site says that I can use a spray adhesive or 'tape' on the poy joints. I don't have much confidence in a gapless joint joint using the sprays. So, that said, what would be a good tape? Silver ducting tape and clear, non-stranded packing tape has been suggested. Opinions welcome. That's about it! TIA, folks.