I need to re-seal my bathtub. I removed all the old caulk because the
guy at Ace Hardware said that new material won't always make a seal
when added to old. Is this correct?
There are some gaps up to about 1/4" that need to be filled. Should I
first fill these gaps and let the caulk dry, then come back and make a
nice neat seam?
Finally, is there a type of caulk that has some chemical that will
prevent mildew? My wife says that if this stuff doesn't exist,
someone should be able to get rich from her idea.
Agreed. Taping both sides makes the work so much easier and lets you
worry less about screwing up.
The other tip that finally got me making really nice caulk beads is:
o do only about 24" at a time
o keep a cup of water with dish soap in it. Moisten your
clean finger to tool the bead after laying it down with the
caulk gun. Clean caulk from finger with a paper towel
o Once tooled, don't f with the caulk again.
By the time you're done with an entire bath/shower, you'll feel
confident enough to do some things without tape and it'll actually
look good. The soapy finger trick though was huge for making it
look professional. My tile refinishing guy I have to credit for
giving that tip to me.
After trying other brands, I too have a strong preference for that
Logic tells me that once caulk is fully cured, no additive will prevent
mildew because it has become inert. Mildew needs only moisture and
food, the spores are everywhere, so the key is not feeding it.
Gotta get the seam as clean as possible, including wipe with
full-strenghth bleach just prior to caulking. Make sure all moisture,
grease and soap scum are gone and area is dry. Gaps can be filled with
backer rod - firm foam "rope" sold in the caulk department. Comes in
different sizes. Painters' tape helps get a nice smoothe edge, but
needs to be removed right away.
If there is a little slant to the tub or floor to be caulked, such that
it collects standing water, it will probably grow mildew. Soap scum is
yummy food for mildew.
The 1/4" is kinda' on the edge -- they make "backer bead" for filling
the bulk of a sizable crack. Serves two purposes -- first, it's likely
there's really nothing much behind that opening so you start squirting
in caulk and it just goes into space and you use much more than needed
for no real purpose. Secondly, larger gaps don't seal as well and tend
to pull away at the edges more easily. All in all, I'd probably
recommend some backer first.
Mildewcides do exist -- think of the famous Kilz primer. I believe all
major manufacturers now have products which contain such. Undoubtedly
they won't be 100% effective, but I suspect the manufacturers will have
test data that supports improved resistance.
I'm getting ready to do my tub, and there are these 1/4 circle
ceramic pieces over the seam. After I get everything taken apart
and the old caulk cleaned up, how do I put it all back together?
My base plan is to caulk the seam, wait a day, then put the
ceramic parts back and caulk the resulting two seams of
those. Is that the right approach?
I just wonder if I should be treating them like bricks and caulking
the edges of the cercamic before I stick them on. :-)
And has anyone used this Caulk Be Gone Stuff? Does it work and
do I have to worry about the residue affecting the new caulk?
On 29 Dec 2006 12:12:54 -0800, firstname.lastname@example.org wrote:
I've used this product (Caulk Be Gone Stuff?) with great results and
absolutely no damage. In another thread I could not think of the name
of it. It works slower on silicon caulk and faster on a latex.. Just
let it work awhile and don't rush or you might to do a second round.
I like it for jobs that are in tight spaces or a pinch, but especially
that you can leave it on and got to lunch... no harmful affects. Clean
well before new caulk.
"Well, it doesn't happen all the time, but when it happens, it happens
Thanks to Mikepier, Norminn, and dpb for your comments. I'm going to
HD in a few minutes to get some blue masking tape, backer rod or bead,
and some GE Silicone II for Kitchen and Bath (or equivalent).
How often does this job have to be repeated? Like once every two or
three years or what?
I'm sure I'll only use like maybe 1/4 of a tube at most. How long
will it keep and what's the best way to keep the remainder fresh?
Fill the tub so that it's weight pulls down and the gap widens, then
No luck on saving unused caulk beyond a month or two here.
Use it where you can, remember it doesn't hold paint.
Bob Simon wrote:
Oh, and make sure you get silicone, not latex. Get an extra tube and
practice on a cardboard box until you get the hang of it. Caulking
doesn't generally have to be repeated if done right - absolutely clean
and dry to start. Caulk is more inclined to get mildewey if not applied
smoothely. Also, if there are spots that collect water, such as a tub
rim that isn''t level, it helps just to wipe it dry after use. Of
course, a good exhaust fan.
Yes, remove as much of the old caulking as you can. Clean everything as
best as you can to remove soap scum or mildew that might affect adhesion.
Also you may want to wipe everything down with rubbing alcohol to remove
any oils that might be present from the previous cleaners.
You should be able fill a gap that small with the caulk in a single
application. But if you have larger gaps, you should probably pick up
some "foam backer rod" and fill the majority of the gap with the backer.
It comes in various sizes and is usually located in the painting section
of hardware stores (though some stores put it in the insulation
The most reliable way I have found to produce picture perfect seams is to
use a caulk labeled for "water cleanup". You apply the caulk as usual,
then run your finger along the seam to smooth it out. Especially with
larger gaps, you may have to add more caulk and redo the finger thing.
Then, you need a bucket of water and a sponge. Get the sponge wet, and
wring out the majority of the water. Then use the wet sponge to wipe the
caulk joint down. Rinse the sponge in the bucket, wring out the excess
water, and repeat for the rest of the seam. Repeat the wipe and rinse
procedure as often as needed to complete your project.
The beauty of this approach is you can clean up places where you applied
too much caulk, or apply more caulk to areas you take too much out of and
The end result is a very clean looking joint.
There are many caulks available that are mold and mildew resistant.
They're usually specified as "bath" or "shower" caulks, but read the
label to be sure.
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