Looking for tips on air sealing tub plumbing slab on grade
I am looking for suggestions how to air seal around plumbing rough in for a tub on a slab. Normally we build a 12″x16″ 2x box, bring our pvc into the box, usually leaving the pipe long and a little deep in the sand and pour our concrete around the box. Later when we set the tubs we dig up the pvc, cut to length, add trap, fill sand back in, then pour 1 or 2″ of concrete to seal things up.
I would like to do a better job air sealing this location, everywhere else we are taping our poly to any penetrations through the slab.
Also we are installing 2″ xps under the slab.
Any suggestions on how to approach this area?