Mortar Bed Bathtub Or Not...?

[MikeGA]

I'm going to be installing an American Standard whirlpool tub (link to product below). I've installed acrylic tubs in the past with no mortar bed. I've ensured that it was level on all sides and screwed them directly to the studs and have not had an issue. However, everything that I've read about this tub states that a mortar bed be used. What are peoples experiencing with having a mortar bed.

Two reasons why I'm hesitant on installing a mortar bed.

1. Once it's dry, you're screwed if there's a leak that you need to fix. You really dont know if there's a leak until you do a final install and test it.
2. I've seen tubs where over time the mortar cracks and damages the tub because the acrylic pretty brittle, not like cast iron.

Thoughts???

https://www.homedepot.com/p/America...ool-Bathtub-in-White-2425LC-LHO-020/100479127

 

[Terry]

Their instructions

This bath must be supported along its entire bottom. Use mortar as bedding material (do not use sand or foam). Apply enough mortar to support the complete bottom of the bath. After the mortar has been poured, and before it sets, position whirlpool or bath within recess until the rim is leveled against the leveling stringers (see "Typical Recess Installation") shown below.

The rim of the bath must not support weight. Allow the mortar material to completely harden before applying weight to the rim or bottom of the bath. Any finish material such as tile or wall board must be self-supporting if it contacts the deck of the bath.

And my thoughts
Sometimes the tub slides in and sets on the floor just fine. There are times when you don't have a level floor and that is when some leveling may be needed. You will know soon enough if you have a floor that is flat and level.

 

[Sponsor]

 

[MikeGA]

Their instructions

This bath must be supported along its entire bottom. Use mortar as bedding material (do not use sand or foam). Apply enough mortar to support the complete bottom of the bath. After the mortar has been poured, and before it sets, position whirlpool or bath within recess until the rim is leveled against the leveling stringers (see "Typical Recess Installation") shown below.

The rim of the bath must not support weight. Allow the mortar material to completely harden before applying weight to the rim or bottom of the bath. Any finish material such as tile or wall board must be self-supporting if it contacts the deck of the bath.

And my thoughts
Sometimes the tub slides in and sets on the floor just fine. There are times when you don't have a level floor and that is when some leveling may be needed. You will know soon enough if you have a floor that is flat and level.

Thanks Terry---My floor is level, I installed a second sub floor of 3/4" leveling it off in the process. I'll then screw the tub directly to the studs. Based on this...what would you do?

 

[Chucky_ott]

When I installed my tub, I placed a sheet of poly vapour barrier under and above the mortar bed. That way it didn't stick to the tub or sub floor. You just need it to fill any gaps between the floor and tub to make sure it's fully supported. It doesn't need to stick to anything.

 

[Chucky_ott]

Actually, I think I just put the poly on top of the mortar bed so it didn't stick to the tub. I wanted the mortar to stick to the floor so it didn't move around.