Hi there
Been looking over your bathtub leak problems but
have not seen anything that will explain mine.
I do have a leak from somewhere that is coming
through the heating vent in the bathroom downstairs
directly below the upstairs tub.
Ok so here is what I have checked so far.
can run both bath and shower faucets with the drain
hole open (no leaks) can pour water down the overflow
(no leaks) if I fill the tub and immediately empty it (no leaks)
But if I fill the tub (below overflow) with the drain plug in and wait about two minutes the leak starts. The drain plug is secure
and I can hear no water leaking through it when the tub is
full. All I can demise is it is some kind of weight problem that after a certain amount of time with the full tub causes the leak.
As soon as the tub is emptied about a minute later the leak stops.
thanks for any help

 

Walt - I don't know the source of your leak, but if you're getting water into a vent (I'm assuming powered) it might be better to fix this before it turns into a more serious problem.

Have you thought about opening the downstairs bathroom ceiling to do a little exploration. The leak should be around the tub drain or it's trap. Just cut a hole and peek around with the tub full of water. Be sure to kill the power to the vent fan first.

 

Hi there
The water is coming out of a forced air furnace vent
so thankfully no electrical. Also I failed to mention in first post
that I can see the drain pipes and trap from the laundry room
next door and I can also see the faucets leading to the taps
and no water is running down either of these but your probably right seeing it's nothing obvious I may have to open up the ceiling around the heat vent to see where it's coming from Like I said in the title this is why such a mystery why does it start not before but after 2 minutes of full tub and why does it stop when tub drained. plus with the stopper in the tub where would water be getting into the drain? thanks

 

It is coming from the rim of the tub drain itself. The plumbers putty or silicone caulk under the chrome rim has failed. The reason it did not leak while running tub only is you weren't developing enough head to cause the pressure to force water out some small gap. 'Water tension' (physcial property of liquids) itself was preventing the leak. But when you filled the tub, you created enough psi that overwhelmed the water tension, and hence the leak.

Unfortunately you will have to redo the flange/strainer piece with new caulk. They unscrew. You can use a tool called a "dumbell" if you have cross hairs. Bottom line is they unscrew. Some can be difficult. Then you have to hope that the horizontal arm under the tub does not fall down, making it hard to thread in new strainer (with say silicone caulk under the rim.).

A worst case scenario and you may have to cut into the ceiling. Because if that horizontal drain pipe that goes from the strainer to the vertical drain drops enough under it's own weight, this could disturb the next nut/washer downstream so that then this goes to leaking after you make your initial repair.

 

Thanks for your post and that still may be
part of the problem but last night I did a thorough
inspection of the tub itself. I phoned the previous
owners for help because they installed the tub
9 years ago. I then recalled after talking to them
they owned a large dog and I suspect they washed
it in the tub. Sure enough after close inspection
I found to holes in the actual tub the size of a small
nail head that looked like they had possible been
repaired with liquid enamel but now were wide open
from previous experience with kids pools I know
how much water can leak through a pin size hole.
So I guess my next question now would be is how to
repair these holes properly.
Thanks Again

 

Ahhhhhhhhhhhhhhh. Well, at least you found it. Sorry I forgot to mention that, but when I see fiberglass tubs that have a leak, I take off my glasses and take a real good look at the bottom of the tub for holes or cracks.

You could repair with actual fiberglass resin and even some colored gel-coat to match. An auto body shop would give you a little if you told them what you are trying to do. I've done that. Or use quick set 2-part epoxy or use some GOOP [ a product that comes in squeeze tube sold in hardware stores and home centers) and is like a cross between epoxy and clear silicone caulk.] (I currently have a gaping crack/bust out in a shower repaired with that, where tenant dropped a heavy object into the thin-walled shower base.)