Joint compound failing.

6 years ago paint started falling off the walls in an interior bathroom. Spot repairs were unsuccessful in finding any well adhered paint. Ceiling was also dropping paint and popcorn, pretty much anywhere in the whole room there was joint compound from the original construction (1977) the paint had let go and was only clinging to the wall because of the latex topcoat. Attached is a picture of the ceiling paint letting go.

I used a pull scraper and removed all the loose paint down to the sheetrock and tape joints. The paper was pretty torn up so I refloated the entire wall with a 12in joint knife and multiple thin coats, sanded, then applied two coats of Original oil based Kiltz followed by two coats of Behr Premium Plus in high gloss white. I think I sealed the wall with Kiltz before appling the new joint compound, but I can't remember for sure.

Now the top coat is cracking all over the room and starting to peel off the wall again. I grabbed a sample and examined it under a microscope and it appears to have failed in the joint compound. I am tempted to gut it to the studs and start over, but can't afford the cost of replacing the shower tile right now.

Any suggestions or criticisms?

 

What's the humidity level like in there/does a fan get run with showers?

 

How much original paint was still intact when you did the work?

 

The fan is run for about an hour after someone showers, but not during. It vents to the attic under decking where the air handler is installed, I think as I have never been able to find its vent hose. Been a long time "round-to-it" to route it out of the house. I am suspicious it dumps moisture into the insulation which then seeps through the drywall from the backside.

Very little of the original paint in the room was viable, only a few areas where the paint was applied directly to the drywall paper. Any tape joints, corners, or mudded over nail heads there was just no adhesion. I scraped all 4 walls and ceiling until there was no more paint in the room.

 

If you suspect that the fan is dumping moisture into the interior walls, making the drywall moist from the other (non-finished) side, then I think there's little you can do from the finished side to stop what you are seeing. On the other hand, you did get 6 years from your repair, and if your fan is simply moving moisture from one side of the drywall to the other, you might think it would have failed much earlier. Of course, you did a great repair job with two coats of oil-based primer, so maybe it does take six years to fail.

Is there anyway you can replace all the drywall w/o doing behind the shower tile?

It also seems like you need to find the other end of the fan vent and ensure that the moisture is properly handled. Good luck!

 

Hope they didn't vent your bathroom like they did mine. Put the fan in and ran vent tube toward the outside wall and then never stopped. Just left open vent between joist. No outside exit anyplace.