On average, it takes three days to completely dry wet drywall.
While drywall is made of some pretty sturdy stuff, it can sustain damage when exposed to water for too long. If moisture damage isn't addressed swiftly, the structural integrity of the drywall becomes compromised, causing it to become soft, weak and susceptible to mold growth.
Even a reading of up to 17% means that the drywall is salvageable, but any moisture level above 17% tells us that the drywall has been compromised and will need to be replaced, or cannot be used.
The 48-72 hour window is critical to prevent mold growth as it usually takes 24 to 48 hours for mold to germinate and grow. Once fungus gets a hold on a drywall surface, it can be the breeding ground for thousands of spores and quickly spread in the air around the wall with every passing hour.
Generally speaking, for drywall, a safe moisture content (%MC) would be less than 1% MC. Anything above 1% MC in drywall would indicate a level of moisture that could compromise the integrity of the gypsum board.
Use fans to move air around the damp walls. Also use dehumidifiers, which can help remove moisture from the air and walls. Professionals use tools like moisture meters, infrared imaging devices, dehumidifiers and heavy-duty fans. That ensures the walls are truly dry before further repair, painting or refinishing.
At the far end, drywall mud, also known as joint compound, needs to dry for 24 hours between each coat and before sanding, priming, and painting. The 24 hour drying time recommendation can be applied to nearly all factors.
Check the instructions on your paint can for a suggested dry time, and if you're still unsure, give it 24 hours.
How long does it take for water damage to dry? It depends on several factors, but in general, you can expect areas in your home exposed to water or moisture to dry in about five days. Sometimes it takes as little as two days to dry an area and other times it could take several weeks.
The necessary period to dry out the ceiling will vary based on just how wet the ceiling got. It can take a minimum of two weeks, but sometimes up to four weeks.
Walls made of drywall or sheetrock are very porous which makes them susceptible to mold as long as there is a constant level of humidity and moisture in the air. The wood particles on drywall provide a source of food for mold and traps moisture, which speeds up its growth.
Can you paint over damp? No. Never paint over a damp wall. Damp is caused by a variety of structural failures, as detailed above, none of which can be fixed by painting over them.
You can paint over a dirty, glossy, chipping, and flaking surface, but don't expect your handiwork to hold up over time. For new paint to stick, your interior or exterior surface needs to be clean and free of dust that could interfere with your paint's ability to adhere to walls, trim, and ceilings.
Do professional painters wash walls? Yes! For exterior painting, we usually power-wash the surface, or sometimes hand-scrub, to make sure it is free of surface contaminants. Inside, pressure washing is not an option, but in many cases the walls need to be washed prior to paint application.
Plasterboard is no exception. Before an assessment can be made about the integrity of the plasterboard, it must be allowed to dry completely. Wet plasterboard cannot be assessed and reparation work and/or painting should not be undertaken before it has dried.
Damp patches, blotches or streaks are usually the first noticeable signs of moisture in walls. Their color, which can range from brown to dark yellow, can dictate the cause of the moisture. Other indications may include peeling paint, crumbling, discoloration, cracking, and hanging of drywall tape.
As previously mentioned, mold thrives in humidity levels of 55% or more. Humidity levels can vary throughout the house. Common areas of concern are kitchens, bathrooms, and laundry rooms where water is frequently present in large quantities.
You should be aware that a moisture reading of 0-15% is quite normal and gives no cause for concern. However, moisture readings in excess of 15% indicate the need for further inspection. Levels between 25-30% indicate that there may be water ingress, meaning that remedial work could be required.
any moisture content above 16% reading is considered damp. Most meters are fairly accurate now,even the cheaper ones.
We strongly recommend a primer that is only made from acrylic. It works well with a wetwall and ensures the result doesn't look tatty. It is best to apply one coat, allow it to dry and then apply a second coat.
Most mold is unmistakable, but sometimes small or largely hidden growths just make a surface look dirty. A quick test for mold can be done when you dip a swab in diluted bleach (1 part bleach, 16 parts water) and dab it on the wall. If the spot quickly lightens (or keeps coming back after cleaning), assume it's mold.