WHAT CAUSES DRYWALL TO BULGE OR WARP OVER TIME?

What Causes Drywall to Bulge or Warp Over Time?

What Causes Drywall to Bulge or Warp Over Time?

Blog Article

Drywall, also known as gypsum board or sheetrock, is a popular building material used in walls and ceilings throughout residential and commercial buildings. While it’s generally durable and affordable, over time you may notice signs of damage such as bulging, warping, or bubbling. These changes not only affect the appearance of a room but may also point to underlying issues that require prompt attention. Understanding what causes drywall to bulge or warp is essential for both preventing and effectively repairing the damage.


In this article, we’ll explore the most common causes behind drywall deformities, how to identify the symptoms early, and what you can do to fix or avoid them in the future.






1. Moisture and Water Damage


One of the most frequent culprits behind bulging or warping drywall is moisture. Drywall is highly susceptible to water because it’s made from gypsum plaster sandwiched between paper sheets. When exposed to excessive humidity, leaks, or flooding, the board absorbs moisture and begins to swell or warp.



Common Sources of Moisture:




  • Leaky roofs or windows




  • Broken or dripping plumbing pipes




  • High indoor humidity or poor ventilation (especially in basements, bathrooms, or laundry rooms)




  • Flooding or water intrusion during storms




When drywall gets wet, the paper backing can bubble, peel, or separate from the core. Over time, the drywall can sag or bulge, particularly if it dries unevenly.



What to Look For:




  • Soft or spongy areas on walls




  • Discoloration (brown or yellow water stains)




  • A musty smell (indicating mold or mildew)




  • Peeling paint or wallpaper




Solution:


Moisture damage needs immediate attention. Locate and repair the water source first. If the drywall is only slightly affected and mold-free, you may be able to dry it and patch the damaged area. However, if the board is soft, crumbling, or moldy, replacement is usually necessary.


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2. Poor Installation


Sometimes drywall issues stem from how the material was installed in the first place. Improper installation practices can set the stage for warping or bulging years down the line.



Common Installation Mistakes:




  • Overdriven or uneven screws/nails causing stress points




  • Failing to secure drywall sheets to enough studs




  • Improper taping or excessive joint compound




  • Not allowing compound to dry fully between layers




These errors can lead to seams becoming visible or materials shifting over time, creating the appearance of bulges or waves.



Solution:


Minor surface imperfections can be sanded and refinished. In more serious cases where the entire sheet is insecure or bowed, it may need to be removed and reinstalled properly with adequate support and level alignment.


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3. Foundation Movement and Structural Shifting


A home’s foundation naturally settles over time, but more dramatic structural movement can distort walls and ceilings, including drywall. When the building’s frame shifts, it puts stress on the wall system, which can cause drywall to crack, bow, or bulge at stress points.



Causes of Structural Shifts:




  • Expansive soils or erosion under the foundation




  • Earthquakes or nearby construction




  • Poorly compacted soil during home construction




  • Tree root intrusion




Even small amounts of shifting can lead to drywall movement, especially at joints or around doors and windows.



Signs to Watch For:




  • Drywall cracks radiating from corners




  • Doors and windows sticking




  • Warped or uneven flooring




  • Gaps between walls and ceilings or trim




Solution:


If you suspect a foundation issue, consult a structural engineer or foundation repair specialist. Addressing the root structural cause is critical before repairing the drywall, or the damage will return.


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4. Temperature and Humidity Changes


Frequent changes in temperature and humidity can cause drywall materials to expand and contract. Over time, this movement may lead to warping, especially in environments with extreme seasonal changes or poor climate control.



Problematic Conditions:




  • Unheated garages or attics




  • Homes without central HVAC or humidifiers




  • Seasonal homes that are left unconditioned for months




Paper and gypsum are both responsive to moisture and temperature. Inadequate insulation or vapor barriers can make the drywall more prone to deformation.



Solution:


Improving climate control in the home—such as adding insulation, sealing drafts, and maintaining consistent indoor humidity levels (ideally around 40–60%)—can help prevent future warping. Any bulged drywall may need to be replaced or refinished.


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5. Mold Growth Behind the Drywall


Mold is not just a health hazard—it’s also a sign of moisture intrusion and can cause the drywall to deteriorate from the inside out. As mold spreads, it can weaken the drywall core, leading to warping, bulging, or bubbling.



Why It Happens:




  • Persistent dampness behind the wall




  • Poor ventilation in bathrooms, basements, or kitchens




  • Long-term leaks from plumbing or roofing




Mold often develops in hidden areas—behind baseboards, inside wall cavities, or under wallpaper.



Signs of Mold:




  • Musty smell




  • Black, green, or brown spotting on walls




  • Soft or distorted drywall




  • Allergic reactions indoors (sneezing, coughing)




Solution:


Remove any affected drywall completely, and treat the area with a mold-killing agent. Professional remediation may be necessary if the contamination is widespread.


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6. Pest Infestation


Believe it or not, pests like termites or carpenter ants can damage drywall, especially if the material is adjacent to wood framing that’s been compromised. Insects can create tunnels or cavities, which leads to soft spots or visible bulging.


Rodents can also chew through drywall, weakening its structure and causing bulges or holes.



Indicators:




  • Small holes or grooves




  • Sawdust or droppings near the baseboards




  • Hollow-sounding sections of drywall




Solution:


Have a pest control professional inspect the area. Once the infestation is eliminated, repair or replace any damaged drywall sections.


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7. Age and Wear


Even with ideal conditions, drywall doesn't last forever. Over many years, materials may start to degrade naturally due to age. Paper can become brittle, screws may loosen, and minor damage can accumulate into noticeable deformation.


Older drywall may also suffer from:





  • Dry shrinkage around joints




  • Surface blistering




  • Sagging ceiling panels due to gravity




Solution:


In older homes, it may be worth assessing whether the drywall should be replaced entirely during major renovations. Otherwise, patching or re-skimming the surface may help improve appearance and integrity.


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8. Improper or Excessive Joint Compound Use


During drywall finishing, joint compound (also known as mud) is applied to seams and fasteners. If applied too thickly or not smoothed properly, it can create raised or uneven surfaces that look like bulging over time.


Improper drying between coats or poor sanding technique can exaggerate this problem.



Signs:




  • Raised seams or patches under paint




  • Uneven texture or shadow lines




  • “Speed bump” look along joints




Solution:


Carefully sand the high spots and reapply thin, even coats of joint compound. Finish with proper feathering and priming before repainting.


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Prevention Tips


To minimize the risk of drywall warping or bulging, consider the following preventative measures:





  • Fix leaks promptly and monitor for moisture issues




  • Use dehumidifiers in humid climates or damp rooms




  • Ensure proper drywall installation with enough screws and support




  • Use mold-resistant drywall in high-moisture areas (e.g., bathrooms, basements)




  • Control indoor temperature and humidity consistently




  • Don’t overload walls with heavy items not properly anchored




  • Schedule regular home maintenance inspections, especially for roofing and plumbing




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When to Call a Professional


While minor drywall bulges can be repaired by a handy DIYer, more serious damage—especially from structural issues, mold, or persistent moisture—warrants professional help. A general contractor, home inspector, or drywall specialist can assess the root cause and recommend the best course of action.


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Conclusion


Drywall bulging and warping isn’t just a cosmetic problem—it’s often a red flag that points to deeper issues such as water damage, poor installation, mold growth, or structural shifting. Understanding the cause of the deformation is the first step in making a lasting repair. Whether you're dealing with a minor bubble or widespread sagging, timely attention can prevent further damage and maintain the integrity of your living space.

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