Hi, I have installed a new shower pan in my master bathroom. The help I found here helped me do the job, I would like to know if I need to put a waterproofing paint over the mortor and the backer board. The pan liner comes up about one foot behind the backer.

Please help my wife would like her bathroom back.:confused:

Boy...

You can plan on getting a different answer from almost anyone you talk too...

I didn't use a waterproofing paint on my cement board until just a few years ago when I started getting into steam showers. Here, the waterproofing paint not only guaranteed a waterproof wall, but also added an additional layer of mold-protection... important in steam showers!

Anyway, hardiebacker makes a mold-resistant cement board that I used for quite awhile WITHOUT using the waterproof paint over it and I never had a call back or any issues... but then we mudded and taped the joints with a modified-thinset mortar so that there really was no way for water to get through the board as long as grout job held up... ;)

Anyway, since this is your house I would take a few minutes and consider using the waterproof paint (over the taped/mudded joints)... certainly can't hurt anything and it also acts as a vapor-barrier... also required in many areas today!

Be sure to check out the hardibacker website for information on exactly how to install the cement board correctly... and in this case, follow the directions exact! These guys know the product very well!

James Hardie: HardieBacker 500 backerboard

Scroll down the page and find wall installation!

Let us know if need more information...

MARK

Thanks Mark, I am using Hardie backer on the walls. I would like to know if it is helpful of harmful to put the waterproofing on the concrete shower pan. The stuff I have is form homedepot Redgard waterproofing and crack prevention membrane. It says it can be used as ashower pan liner.

I know of the stuff...

If you have installed a vinyl shower pan membrane so it rides up the walls as you said in 1st post then there should not be a need to use a waterproofing paint on the floor.

I have heard you can use this as a pan all by itself... but I'm not going to try it as the pan alone... ever... ;)

I would use it on the walls.

MARK

Mark thanks a ton, you helped more than you know, and saved me some $$$$$$$. That will make my wife very happy because I can start laying tile tomorrow.
Lee