Bathroom Paint and Plaster Problems, Latex kitchen/bathroom paint

[Bond Milton]

I have a problem with paint, plaster and corner bead in
a bathroom. It is located on a short wall next to the corner
of a fiberglass shower and tub. Originally the space for
the bathtub turned out to be shorter and narrower than the
new tub required so a short wall was installed to make a
space wider than the tub. The wall had a mildew problem and
than plaster damage and rotten 2 x 4 wood. Last spring I
replaced the water damaged drywall, the rotten wood with
chemically treated lumber, used indoor/outdoor spackling
and painted with what was supposed to be bathroom/kitchen
rated paint. The paint was not supposed to need primer and
was latex water based. I followed the instructions about time
between additional paint coats. The old corner bead had some
rust which I sanded off before painting and the section that
was replaced with new galvanized corner bead probably lost
its coating at the corner from sandpaper. Six months later
the new plaster area and the old area that were painted do
not have any problem with mildew (Paint was mildew resistant.)
but I have paint cracking, rust causing the paint to flake
off on the old corner bead and some of the spackling coming off
after exposure to water. I would have assumed that four coats
of water resistant paint designed for bathrooms/kitchens would
protect the plaster underneath. I have some deformation of
the plaster possibly caused by nails in the original dry 2 x4
moving up and cracks probably caused by the underlying drywall
cracking. I have replaced the shower curtain and installed a
plastic corner guard between the tub and the shower stall to
help prevent water splashing on the short wall. Most of the
problems were from the paint which was purchased at Miejer* and
is apparently the brand "magical". The next thing I intend to
do is sand all the cracked and loose paint off. Sand off any
high points on the spackling and probably dig out the areas
that my be nails coming up and fill. Sand out the rust on the
old corner beads again. Patch the plaster with DAP CrackSHOT
Spackling Paste Interior/Exterior which I have very good results
with elsewhere. Paint with an oil based primer and coat with
urethane (oil) based paint. How would you fix this problem
permanently?

Thanks everyone,

Bond

*Miejer is similar to K-Mart or WalMart in the midwest.

[TinMan1332]

>I have a problem with paint, plaster and corner bead in
>a bathroom. It is located on a

<some text deleted>

You will never, ever cure this problem with paints primers or exterior spackle.
You need to start over and use tile or anther surface that will stand up to
moisture. Either that or alter the design in some other way so it's not
exposed to moisture.

[Poe]

The dry wall is wet, its that simple. What you've done is sealed the
moisture in, rather than preventing moisture from getting in. What
you'll need to do (an I know you don't want to hear this) is rebuild the
wall. Over time the caulking fails around the tub and the dry wall act
like a wick, and soaks up the moisture.

Tear out the old wall I'm sure you will find that the bottom of the wall
is wet and rotting. Rebuild the wall using regular 2x4's (don't use
treated wood, the chemical in the wood will leech into the dry wall and
create the problem your trying to avoid) Board it with Green Board,
that's that green dry wall stuff and is meant for damp areas the paper
coating is mildew resistant. Tape it,Prime it, and paint it with a
mildew resistant paint. and be sure to use a good quality silicone
caulking. The quality of caulking you use will determine how long it
will be before you have this problem again, so don't skimp.

I'm sure you didn't want to hear that, but it's what you have to do to
fix the problem. During my time as a contractor I've personally done
many of these jobs.

[RamblinOn]

Don't know if I read the entire situation right, but the galvanized
corner bead likely continued to rust due to improper preparation or rust
underneath that continues to spread. Painting without primer may have
encouraged more rust, or minute gaps in the paint coating. Use a good
primer intended for the surfaces and you should be fine. Check out this
site:
http://benjaminmoore.com/h/hb3.html#pic6

[Bond Milton]

TinMan

It is not exposed to direct liquid moisture now.
Certainly water vapor in the air can be a problem
in a bathroom. This should have less exposure than
the ceiling and upper walls of the shower/bathtub.
The walls are covered with water resistant wall
paper outside of this area next to the tub. The
ceiling and upper walls of the tub/shower (not
protected with fiberglass) are plaster covered with
20 year old paint. The old paint has mildewed areas but
no water damage. The vent fan has been upgraded also.

Bond

[Bond Milton]

RamblinOn

Based on the condition of the old corner bead that was removed it
appears that the corner bead installed in 1983 was not galvanized.
The new galvanized material does not have a problem. The site you
recommended was useful, Thanks. I intend to sand again and paint with
an oil based primer. I have been told that latex does not seal as
well as oil based paints and may have minute gaps. Most of the
people I have talked to in paint stores were young and had no
practical experience. I am not sure if I can remove all of the
rust and it may continue to spread.

Thanks,

Bond

[Bond Milton]

Poe,

I wrote a long description because some things are difficult
to explain without pictures. The problem area can be mostly be
seen from behind the wall because the bedroom closet has an
access panel to get to the tub plumbing. When I repaired the
2 x 4s with treated lumber I used three scraps from an old
project that the longest was only 7 inches. New treated lumber
is usually quite wet but these four year old pieces were bone
dry. Indications when I did the repair and when I checked
with a mirror and flashlight today are that the water mostly came
from the floor of the bathroom. The drywall was wet from the
outside and when it was repaired all the damp, damaged material
was replaced. What didn't come from the floor was splash and
condensation on the wall. Not removing the damaged plaster
and repairing it immediately after I noticed the mildew made
the problem even worse. When I finished the repair I caulked
the floor, the edge against the fiberglass tub and the edge
against the wall paper. The old dry wall was definitely acting
like a wick when water was spilled on the floor. I repaired
and caulked the old vinyl floor but a future project will replace
the vinyl and repair the rotten floor near the toilet. I will be
putting on another layer of caulking when I redo this. I considered
buying green board for this repair originally. What I will do is
try to repair this one more time and if it doesn't work later the
entire stub wall and bead edges will be replaced with new material.
According to the following site:
http://benjaminmoore.com/h/hb3.html#pic6
I did not wait long enough for the spackling to dry before painting.
According to the spackling instructions I did. I think the problem
may have been mostly damp spackling and defective paint. If I am wrong I
will probably do it your way.

Thanks for your help.

Bond

[Tony Hwang]

Hi,
Used green drywall(water resistant one)? Have good ventilation in the
bathroom?
Definitely it is moisture problem. If you used ordinary drywall piece,
that is no, no, in bathroom. How about using tiles on top of green
dry wall meaning doing it over again.
Good luck,
Tony

[John]

Is it possible that you have a leak behind the wall, perhaps from the
pipes or the roof vent?

John