Fixing water damaged drywall

Posted by Matt Buchanan

One of the most common types of water damage people discover in their homes is bubbling, warping or discoloration of their dry wall. Commonly referred to as a wet spot, it’s pretty unmistakable and should be a very serious cause for concern. As we’ve discussed many times in our water damage restoration blog, any signs of a moisture problem should be assessed by a professional water damage company. It could be a very small issue that you can deal with on your own (if you’re somewhat handy and have access to the right tools), or it could be the tip of the iceberg and point to a much larger, more sinister problem. One that if not dealt with correctly could be a massive health risk for your family and a pitfall financially.


What to consider when finding water damaged drywall


We’ll talk in a little bit about how to fix water damage to drywall, but first we need to explain something. Unless your drywall got wet because you threw some water on it, that water had to come from somewhere. If you didn’t have noticeable flooding, then it probably came from behind the wall. Well that should be obvious, so why do we bring it up? Because too many people just try to fix the problem they can see, without addressing the issues they can’t see. Here is an example from


So what happened here? Well, the homeowner explains it quite well…they had a water line burst sending water streaming through out the first floor level of their home to the point where it dripped through their flooring and soaked the ceiling of their basement. Yikes! As a water damage restoration service, we can’t help but point at the fallacy in her questioning: ‘How do I fix the water damage to the ceiling?’. That’s the easiest thing to fix…but she’s completely ignored the bigger problem. That water didn’t just soak her basement ceiling, it probably soaked everything in the subfloor and cavity between her floor and ceiling. You can replace the drywall in the ceiling, but if you don’t dry out the wet areas, you’re just treating a symptom while ignoring the disease.

And when it comes to water damage, the disease is persistent moisture problems that result in 2 things:

() black mold

() a weakened structure

water-damage-drywallAs ‘The Builder’ goes on to address in his answer to Susie’s question above, ceiling drywall can give way and fall on you if it sits wet for any considerable amount of time. That’s what a weakened structure looks like. Floor joists can even sag if they are allowed to rot from water damage. And that’s just the immediate danger. The persistent threat is toxic mold spores causing illness (and in extreme cases of under-developed or weak immune systems even death).

Let’s take the water stain in the picture above. What if you just paint over it? Well, you may be trapping a moisture problem within the ceiling cavity and ensuring you face a huge black mold problem after some time. Once you see it forming on the exterior of the ceiling, you open up to investigate and find this:



Those dark spots are mold infestation. A big, expensive problem. So why are we spending an entire blog post about fixing water damage to drywalls on mold? Because fixing drywall is easy, but if you fix it and ignore the underlying problem (or not address the ‘hidden’ moisture), your problems are going to get much worse before they get better. Don’t underestimate a small water stain in your drywall!


How to fix drywall water damage


There are typically 3 methods that can be employed to fix drywall that has gotten wet:

(1) remove the drywall entirely – this is most commonly done when the water classification is black water, there are multiple levels of drywall, or it has sat wet for awhile (more than 48-72 hours). Here is a video showing how to replace drywall (please ignore the fact there is mold. If you discover mold, you should immediately call a mold certified company. If you don’t, please understand that you’ll be agitating mold spores and sending them into the air and there are significant health risks associated with that type of exposure).


(2) exterior drying – If it’s the case only your drywall got wet (and the cavity behind it, any wall studs, etc. remained dry), you can probably place air movers on the affected area. You’d call them fans, but we call them air movers. Their function is simple: pass hot, dry air over the moisture, causing it to evaporate.

Please note: if you’re going to dry them in this way, you need to also put a dehumidification system in place to capture the moisture. If you don’t, the moisture just travels to somewhere else in the room and gets it wet. We call this secondary water damage, and it’s a common occurrence when an area is dried by homeowners or anyone that isn’t certified as a structural drying professional.


(3) drying the wall cavity as well as the drywall – certain moisture probes allow you to determine the moisture content of areas behind the surface you’re concerned about. If it’s the case you discover wet areas behind the drywall, you have two possible ways forward:

Create a flood cut, essentially removing the wet section as well as 12-18 inches of dry section above it.

Use a wall cavity drying system like Injectidry by boring small holes in the drywall and attaching hoses that pass hot air into the cavity and dry out whatever is behind it.


How dry should the drywall be?


moisture-content-drywallOne thing that trips up homeowners is the belief that things are either wet or dry. In reality, every surface has some level of moisture in it. It needs that moisture to function as it should. So when you’re drying a surface like drywall, what you’re trying to do is get the moisture levels down to ‘normal’ levels. So what are those levels? The answer is it depends on many things, but mostly the relative humidity in your home. So how do you know what level to dry to? Test the moisture content levels of the drywall in an area that is ‘dry’. Once you have that number, you then know the dry standard you’re aiming for.

About Matt Buchanan

I grew up in Irving, TX and left for Nashville, TN for college. After college I lived in Washington, DC and then in Cairo, Egypt. After coming back to the states, I spent a couple of years back in Dallas before moving with my wife to Denver!
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