Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
3,588 Posts
Discussion Starter #1
In my personal house I have a 1 piece tub shower. I believe the floor is 7/16 osb embedded in fiberglass. I've noticed that the floor is far more spongy than the other 2 I have. I don't suspect a leak, or any major impact. I'm about to cover up my ceiling in the basement, which will mean I can't access the floor anymore. Im thinking about filling the tub half full of water and spraying some foam under there in an effort to help stop the deflection. Has anyone done this, and can they recommend a type? Im guessing I want closed cell.? Thanks

Sent from my SM-G935W8 using Tapatalk
 

·
Registered
Joined
·
11,180 Posts
Its worth a shot. Ive done it with Great Stuff Gap filler and it does wonders.


Just make sure to over pump it so its ends up denser after it spreads out
 

·
Administrator
Joined
·
24,068 Posts
If the bathroom floor has proper joist spacing and sheathing, the place to address any "sponginess" is on top of the sheathing, not underneath it. The unit should have been set atop a base of mortar, thinset or foam. Unlikely anything underneath the sheathing is going to have any effect at all.
 

·
Registered
Joined
·
6,949 Posts
If the bathroom floor has proper joist spacing and sheathing, the place to address any "sponginess" is on top of the sheathing, not underneath it. The unit should have been set atop a base of mortar, thinset or foam. Unlikely anything underneath the sheathing is going to have any effect at all.
I think he is going to drill a hole and shoot it through the hole
 

·
Registered
Joined
·
11,180 Posts
I use structolite on new installs. But when I came across something creaky and my only access was from the bottom I drilled a series of 1/4 holes spread around.
With the holes I stick the tip of the foam gun in it and blast until I see it ooze from a nieghboring hole.
 

·
Registered
Joined
·
5,792 Posts
The OP posted that AFTER he covers his basement ceiling he will have no access. Currently, he DOES have access as I read it.

Sent from my SM-G530T using Tapatalk
He currently has access to the subfloor underneath the tub, he won’t once he drywall’s the ceiling in his basement which is below the tub.
 

·
Registered
Joined
·
41 Posts
I didn't say that was possible. I simply stated that the OP comment stated that he wanted to support it BEFORE he lost access by drywalling the basement ceiling.

My guess, as others have stated, is that the OP intends to drill holes in the subfloor and spray expanding foam under the tub. I don't believe he said anything about using drywall mud.
explain how to put drywall mud between a tub and subfloor from below the subfloor
Sent from my SM-G530T using Tapatalk
 

·
Registered
Joined
·
3,588 Posts
Discussion Starter #17
Yes, the tub is on the main floor. I have partial access to the floor sheathing under the tub. (Drill Holes) These tubs are designed, and have built in feet to just simply put it in place and screw it to the walls. The bottom of the tub is actually a couple inches off the subfloor. We'e used probably 100 of these, and I have 2 others in my place that are rock solid on the base. I'm confident its not an installation issue.

It may be that this one was bad, or maybe someone fell in there and keeping it a secret.:laughing: I honestly don't know. It's been this way for about a year that I've noticed with no real change, it just feels soft. I was concerned that the standard great stuff, may lose its structure after a couple years.

I thought if I put a 150 lb or so then added the foam, it would be less likely to cause problems, down the road. It sounds like it's not a concern.

Like tin says, My absolute biggest concern is putting 15 quarter inch holes in the bottom of the tub. :laughing:
 

·
Contractor of the Month
Joined
·
26,075 Posts
I did it and it made my tub creak like a bastard...
 
  • Like
Reactions: JT Wood

·
Registered
Joined
·
41 Posts
Is there a "trouble door" at the faucet end of the tub? If so, you may be able to hammer in a few wedges to raise the tub slightly, and the squash in some structolite as far as you can push it under the tub, then remove the wedges. Let it sit for 24 hours before using the tub.

Sent from my SM-G530T using Tapatalk
 
1 - 19 of 19 Posts
Top