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Falling apart bathroom wall

My shower was built and there were no protective coverings over the walls and now my walls are starting to fall apart. The wood under the drywall (I'm assuming it's drywall) is exposed and looks like it is starting to rot. How can I replace the wall to be able to put a bathtub fixture over the wall?

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Posted 2012-05-03T22:55:13+0000  by piddles56 piddles56


Hi Piddles56, Welcome to the community.

Wow this is a real problem. Its sounds like the tub was in place originally and someone along the way added a shower to it without adding protection for the walls.

The first step is to stop using the shower and check the area for mold, I am sure there is some inside the walls with all that moisture going in there. When cleaning the mold wear a good respirator, old clothes and shoes which you can discarded when finished.

Use a garden sprayer to treat the mold with a water solution containing 20% chlorine bleach. Remove the moldy drywall and wood while wet to prevent mold spores from being spread thought the house.

Be sure to place and moldy material in plastic bags for disposal, and if using shop vac be sure to have a HEPA filter installed to prevent spreading the mold spores around in the house. The spores can be inhaled causing illness.

Remove and replace any wood this is rotted, warped or moldy. Now is also a good time to change out the tub shower plumbing, if necessary, and do any other repairs that are needed.

Once you have the wood replaced, you have several options. You can install cement board and tile the walls, or use green board, (a water resistant drywall) and install acrylic panels on the walls. 


Either will work, your budget and the time you have available will dictate which way to go.

Also check the ceiling for damage, as water in showers often is deflected onto the ceiling.

Consider using tile or water resistant drywall on the ceiling.  If using drywall on the ceiling be sure to paint it with a good quality oil based paint to resist future damage.

The tub has a lip around the top perimeter to accept the wall treatment to make it water tight. Be sure to bring the tile or acrylic panels down to the top of the tub, making sure they cover the lip.

Once your done be sure to seal along the walls and the top of the tub with a good silicone caulk, to prevent any future moisture problems.

Good luck with your project.



Posted 2012-05-04T00:52:31+0000  by Mike_HD_OC

Thank you so much! This helps a lot!! Two more question for you though. The wall that is starting to deteriorate has a window. Is this going to cause any other problems, or am I going to be ok to work around it? Also, when I replace the wood am I OK to take it right out or am I going to have to worry about the wall collapsing? The damage isn't the entire wall, it's about a foot in length (as far as I can tell so far).

Posted 2012-05-05T10:36:58+0000  by piddles56

Slow down....


While bleach is an effective killer of mold, it isn't the best thing to be using on porous surfaces. Let's talk about bleach a bit. Never use bleach full strength. The CDC recommends 1 Cup of bleach per 1 Gallon of water. This solution is more than adequate to kill mold on hard surfaces. The best way to apply it is in a spray bottle and mist the area. Shooting a stream of solution will cause splatter of water droplets, which when hitting the mold will cause the spores to spread. The other problem with using bleach, bleach evaporates quicker than water. This leaves behind moisture that creates a nice breeding environment for new mold growth.


So for your porous wood and drywall surfaces you'll want something other than bleach. If you visit the Paint Department of your local Home Depot, there are products such as EnviroCare's Moldex products and Concrobium's Mold Control. These products will effectively kill the mold and keep it from coming back. If you rip out the drywall and notice a wide spread mold problem and feel you can tackle it yourself, you can rent a fogger from your THD's Tool Rental and fog the area with Mold Control. Mold Control is a salt based solution. Mold doesn't like salt. You won't see mold and mildew at sea side beach areas for that very reason. If it is a wide spread problem, you really should consult a mold remediation specialist. Given the health issues involved, extreme mold in a house is not something to play around with...


Posted 2012-05-05T15:55:08+0000  by Paul

My first choice for the walls would be cement board.Green board  or Mold Tough panels are not approved for use in wet areas.




Mold Tough relates to improved mold and moisture resistance over standard gypsum panels.


Hope this helps.





Posted 2012-05-07T14:15:00+0000  by George_HD_CHI

Hi Peddles56,


Working around the window will be no problem. You can remove one stud at a time and replace them without any danger of the wall shifting. Make sure you replace any pieces with signs of mold or rot.


As to the comments about using bleach, bleach is a very effective mold killer. My recommendation is to kill the existing mold with the bleach and water solution and then remove the effected pieces while they are wet. This will prevent mold spores from being spread to the other parts of the house. 


Be sure to let the area dry thoroughly before closing up the wall. As Steeltoes suggested cement board will be the best product to use to replace the drywall in your bathroom.


Good Luck with your project.



Posted 2012-05-07T17:03:50+0000  by Mike_HD_OC




To follow your logic, if salt prevents mildew growth along the ocean, shouldn't a solution of saltwater act as a preventative if sprayed onto active mold? After the water evaporates, the residual salt would prevent a reoccurance. Of course, salt would also be corrosive to most metals in the area.


Heavy concentrations of salt or sugar have long been used as food preservatives. Both preserve by dehydrating the offending organisms. Likewise acidic vinegar acts as a preservative. It is not a coincidence that pickles have both salt and vinegar in them and don't need to be refrigerated.. Vinegar is also used as a disinfectant when cleaning wooden cutting boards.


The bilge of old wooden ocean going sailing vessels did not rot because the bilge water was salt water. Again, salt as a preservative.


Peanut butter does not support bacteria because of its very low moisture content ( although it does go rancid).


I guess this sounds like theme drift, other than suffice it to say, mildew and algae can't exist without high moisture levels. Keep the surface  dry and it won't mildew. Leave a salt behind, as does Concrobium, and it will not mildew.


I still use bleach as my primary mold killer. It is effective and inexpensive, but I would not want to use it in certain circumstances. It is not a good idea to breath high concentrations of the stuff in confined spaces. Better to go down in that crawl space armed with Concrobium than with clorine bleach!

Posted 2012-05-08T05:32:10+0000  by ordjen

Bleach (sodium hypochlorite) aka Chlor does not fully kill mold.


 Think of mold like it’s a plant. Bleach will only kill (read burn) the aboveground portion of a plant; a background level (root system) will remain.


And with favorable conditions (moisture/air stagnancy) this same plant will re grow (return) in exactly the same spot.

 mold cl..JPG


Like ordjen mentioned; moisture control is the key to mold control.


People tend not to utilize (open) their bathroom window(s) or they tend not to open it in conjunction with door. Also bathroom windows are not as efficient as properly installed power exhaust fan.


@ Paul, ordjen on studs and bleach;


I think it would make more sense to replace molded and rotten studs than to try to remedy them. 9 out 10 times majority of the damage is at the bottom plates not vertical members.





Posted 2012-05-08T14:34:32+0000  by George_HD_CHI


Fortunately, the bottom plates are often of pressure treated wood, often by code. Here again, pressure treated resists mold because it is infused with chemicals toxic to plant life, usually a form of copper or zinc. Mold and algae, being plant life, don't do well in their presence. Unfortunately, the wood preservative products used to surface treatment of wood are not suitable for interior use.

Posted 2012-05-08T15:45:40+0000  by ordjen


ordjen wrote:


Fortunately, the bottom plates are often of pressure treated wood, often by code. Here again, pressure treated resists mold because it is infused with chemicals toxic to plant life, usually a form of copper or zinc. Mold and algae, being plant life, don't do well in their presence. Unfortunately, the wood preservative products used to surface treatment of wood are not suitable for interior use.

Ordjen you are correct,

However pressure treated plates are only used in applications with ground (concrete) contact. For anything above ground white #2BTR or common studs are used. Having said in the original post there is a window present I’m assuming this is a second story bath.


In addition pressure treated lumber tends to warp and twist during and after drying process even when pinned down with the wall studs.Most carpenters avoid using PT lumber for anything else but the bottom plates.


Depending on the location some villages permit  use of standard white wood in combination with the sill pan flashing to prevent capillary rise. Depending on the treatment process typical PT lumber it warranted for only 30 + years.


Posted 2012-05-08T16:07:39+0000  by George_HD_CHI
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