View Full Version : Drop in frame for whirlpool

12-03-2012, 07:44 AM
OK, this is my first drop in frame.

Water damaged sub-floor repaired, joists reinforced with blocking, even put sound proof insulation down.
Now I have a question on the correct height for the drop-in tub.
Here it goes.
Height of the tub deck is 19", lip edge is 2" so the height from the floor to deck lip edge is 17". Now for the vertical frame calculation using 2x4s: Bottom plate 1 1/2, top plate 1 1/2, plywood 3/4, cement board 1/2, tile & mortar 1/2, vertical 2x4s at 12 1/4. This gives me a height of 17". Bottom of deck lip edge is 17" so I should be good, right? (1 1/2, 1 1/2, 3/4, 1/2, 1/2, 12 1/4, = 17) What I did not calculate is the mortar bed the whirlpool will sit in. Do I add another inch for the mortar bed? Meaning the height to the deck lower lip would be 18" and my frame needs to come up another inch? Or do I ignore the mortar bed with the idea that pushing down into the bed will displace enough mortar to make the bottom of the whirlpool practically sit on the sub-floor. The whirlpool is a jacuzzi primo if that matters. comments &/or suggestion appreciated.

1. Am I building to the correct height?
2. Do I mortar & tile after setting the tub in mortar bed or before? (current plan is to set in mortar bed first & use 1" scrap wood to leave space for the cement board & tile & mortar.

12-03-2012, 04:14 PM
Please refer back to the manufacturer's installation instructions and diagram, showing the various dimensions, you can't go wrong then.

12-04-2012, 05:51 AM
Tile first then set the tub ONTO the tile. IF you make the frame higher than "necessary", the mortar bed will fill the gap. For all practical purposes, the tub will be "hanging" on its rim so the mortar bed is only to stabilize the floor.

12-04-2012, 07:30 AM
hj, thank you for the response. The manufacturer's installation instructions and diagram did not discuss this issue which is why I came here. This helps. Trying to be exact here so the tub is supported by it own feet on the sub-floor, in the mortar bed, and not by the drop-in frame. I take it that if I am off a little bit the mortar bed will fill the gap so I should be ok. I would hate to tear it out and start all over again.