WE have a jaquzzi tub, it was here when we bought the house. The brand name
is novi, we have aproblem with the caulk bead retreating from the tub when
filled with water. I can caulk it and it will last for about a month then it
will start to peel away thus allowing water to get behind it then trickle
down to the kitchen ceiling. WE are renovating the kitchen (read toilet
supply rupture thread) and while I have great access to the bottom of the
tub I thought maybe I should look into this fix. As I looked at how the tub
is sitting, first there is the t/g floor boards, then a layer of what looks
like cement then a piece of plywood, a piece of styrofoam another piece of
OSB. All this looks like it is attached to the bottom of the tub with the
same resin that was applied to the underside of the tub. Is this normal or
is only the OSB attached at the factory to the tub as a platform. What I am
thinking is that the styrofoam is compressing causing the cualk to separate.
Any ideas before I hang the new ceiling?
That stackup sounds about right. The foam is for insulation. The ply
and OSB spread the load, and the mortar bed provides the firm support.
I'd be more suspicious of your caulk job. I assume you are talking
about the bead around the top of the tub? It shouldn't peel away
unless the tub is moving a *lot*. When you caulk it, are you positive
you are getting the old film off? Do you clean the area with alcohol
first? Use a good silicone or urethane caulk with mildewcide, and
fill the tub with water before you caulk it.
Call the manufacturer for information on your specific tub's
As far as the caulk, there are caulks that can stretch more - Big
Stretch is one, but they're not the typical caulk used in bathrooms
and might not hold up. Lexel might be your best choice.
Paul has the right idea about filling the tub before caulking.
Probably a good idea to take your shoes off so they won't get wet. ;)
The tub and/or substructurecould be a poorly made design, assuming
that your floor itself is not the culprit. You might try to check for
floor movement by simply placing a regular carpenters level on the
floor and watch for a shift in the bubble as the tub fills. If you are
convinced the floor is quite rigid, then the 'jacuzzi' might as well
be put out on the curb and replaced with something more robust. Good
OK, I think the substructure is pretty strong, the joists are 2" thick rough
cut (type, I'm not sure). I'm looking for a reason to get rid of it!!! I
would much rather take it out and replace the whole thing. I will try the
more flexible caulk. Iwould like to get behind that surround and see if
there is any support for the tub wall back there. The front is well
supported with a 2x4 frame, but I'd be willing to bet that there is nothng
on the back side. The previous owners cut MANY corners in this house. Using
a drop ceiling to hide electrical wiring for one!
If you decide to replace it consider Sanijet. They have no pipes to collect
water and gunk. Each jet is a tiny pump and cleanable. www.sanijet.com
Many hotels are switching to them.
I just ordered one.
If you see flex like that then something is wrong, it would be helpful
to know if the joists are flexing or if the underlayment is
In the kitchen under the tub hang a plumb bob from the joists while
tub is full so the bob is touching the floor, then pull the drain plug
and run downstairs to see if the plum bob rises off the floor with the
joists. If it does then the joists are flexing... so sister the floor
joists under the tub with more wood (while tub full) till no flex.
If the joists are not flexing then the underlayment is, in that case
you will probably have to live with it and cauck the tub with butyl
rubber window caulk instead, that stuff has an enormous amount of flex
Great idea, I will do just that with the plumb bob, I knew that tear drop
hunk of steel my grandfather left me would come in handy one day!
I think that since the joists are thick and heavy as well as having t/g
flooring above that it really shouldn't be moving, but I will check and let
you know, thanks again.
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