Shower Pan Mud

Perhaps I am just unlucky but I have had two showers pans in separate homes fail. Both resulted in mold developing.

I am considering adding a granular chlorine, like shock, to the mud below the pan. My hope is that it will act as a fungicide should I have another leak. Also, the odor of the chlorine should alert me to a shower pan fail.

Does anyone have experience or thoughts with modifying the mud as such?

 

NO! DO NOT ADD CHLORINE! It is a corrosive oxidizer.

Please describe the problem with your showers in greater detail. The title "shower pan mud" may be misleading as to the true cause of your problem. Are you having water leaking of the shower (like into the room below)? Or, do you have mildew in the grout joints between tiles? Do you have cracked tiles or grout joints?

 

Thanks for responding so quickly.

In the present case the shower install was done incorrectly. When the shower was removed yesterday the problem became evident - there was a full circumference gutter board screwed in through the shower pan. The gutter board screws were placed all the way down along the base of the shower so there were dozens of penetrations around the entire circumference of the shower. The water went down to the concrete and seeped to the adjoining rooms in several directions.

Fortunately I have metal studs (it is a condo) so mold was not present on the internal wall structures.

My thought was to put some granular chlorine on the concrete surface below the shower pan so if a future penetration occurred there would be a fungicide benefit - but I certainly don't want to introduce an oxidizer, like chlorine, to the fill below the rubberized pan if it can result in rusting of the studs.

It was just a thought having suffered through this twice already.

The area is drying and next week the shower build will start.

 

I think you should just focus on having the new shower properly constructed. If done right it will be quite reliably leak free. Showers are built all the time. While it's not rocket science it does need to be done properly so I'd put some effort into making sure this next installer knows what they are doing.

 

Yes, clearly the issue is with the the previous installation. One should not jump to conclusions. The area beneath the shower should stay dry if properly constructed. Make sure you have a pre-slope under the pan liner that will channel any water toward the multi-part drain body. Just laying a pan on the existing concrete is not the correct way to proceed.

While this demonstration is on a wood subfloor, you can get a good feel for proper pan installation by reviewing this website - How to build a shower - Building a shower pan with pre-sloped mortar bed, liner and curb.