Drywall bulge is a common issue in which a raised area, swollen lump, or disfiguration of a particular patch of drywall occurs. Not only can a drywall bugle appear unsightly and ruin the aesthetic of your home, but it can also indicate more serious underlying issues, such as water damage, that need to be addressed.
But water damage is not the only potential cause of this. An improper installation such as loose screws or overdriven fasteners can also contribute to bulging and distortion of drywall.
So in this article, we’ll cover all the main contributors to drywall bulge and then discuss how to repair it depending on the root cause of the problem.
What causes drywall to bulge?
Table of Contents
So when you first see this issue occur, it’s easy to want to replace the unsightly panel and be done with it. This could sometimes work if the problem was caused by something innocuous, such as a bit of glue failing.
However, identifying the root cause of the bulge is an essential step before fixing it. Otherwise, the problem will keep recurring. Sometimes this issue can be rectified by simply refitting the drywall, or in more severe cases, a panel may need removing and replacing.
Unless you are pretty confident in your ability to cut, install and finish drywall, we always recommend hiring a professional to do this. But this article should serve as an informative guide so you are as educated as possible regarding approaching the problem.
Water damage
Drywall is designed to tolerate a certain amount of water content (about 5-12%) specifically to give it some resilience against humidity or odd spillage.
However, when the water content becomes much, the panel will inflate or swell with the water content, which manifests as a visible bulge behind the front layer of the panel.
This can occur at any point or position on the wall. It entirely depends on where the water comes from and how the plumbing is arranged behind the wall.
An easy test to check if the bulge is water related is to press it gently with your finger. If it squashes down quickly, there is a likelihood that it’s been water damaged. You can also use a moisture meter which measures the water content.
Or, if the bulge is very severe, set some towels down and poke a small hole in the drywall. If water comes out, it’s time to wall someone immediately, as you don’t want something like rot to set in on the structure of your home.
It goes without saying that before replacing the panel, you will need to have a plumber or repairman deal with the root cause of the water leak.
Loose screws
This is generally something that is caused at the time of installation. Still, it’s also not unheard of to have screws loose over time, such as due to consistent expansion and contraction of an area due to temperature changes.
When a screw comes loose, or there have not been enough screws used during the installation, the natural pressures on the panel by the house will cause it to bow out in that spot.
Providing no drywall cracks or surface drywall damage has occurred due to the bulge, this can usually be fixed quite easily by re-affixing the loose screws or adding a few new ones if not enough were used at the time of installation.
Overdriven fasteners
On the opposite side, overdriven screws or fasteners can often exert excess pressure on the panel, causing visual warping and bulging. Once again, this is commonly an issue that occurs during installation.
When setting drywall panels, the screws will be driven into a fastener, a small plastic fitting that expands as the screw is driven into this. An overtightened screw can break the fastener, or an overexpanded fastener will exert additional pressure on the panel, causing warping.
If there is no drywall damage, sometimes the tightness of the screws can be readjusted, and the panel will return to its normal shape. However, in many cases, due to the softness of the drywall, an overdriven screw or fastener can tear the paper and damage the core of the drywall panel.
This doesn’t necessarily mean the panel should be replaced. In specific scenarios, it’s possible to replace the screw and repair the hole.
Home is settling
If your home is relatively new, or sometimes this can even happen in older homes over longer periods, sometimes the foundation will move slightly or settle.
This is a fairly natural occurrence and not something to be alarmed about, although if you do see significant drywall cracks anywhere, then it’s best to call a professional to look at it.
But as the foundation has shifted, new pressures have been put on a previously installed piece of drywall, causing them to squash and bulge a bit.
You may see old plaster being squeezed out between the bottoms of the panels, indicating that pressure is applied to the panel.
Sometimes you can remove the bulge and re-fill it. It won’t affect the structural rigidity of the home. It’s just an aesthetic thing. But if you are curious, you may wish to replace the panel to see what’s happening behind it.
Poor installation
While bad drywall screws and fasteners are technically also the culprit of poor installation, we are talking about that the panels have not been cut precisely to size, causing the drywall seam to bulge. Even the slightest pressure exerted by an oversized panel can be enough to cause a bulging drywall seam.
It’s possible to remove the panel at fault and trim it down slightly. But this is often best left to someone who can ensure the correct size needed to do a good job.
Failing adhesive
Sometimes instead of nailing the drywall to hold it in place until the main drywall screws are placed, people like to use glue or adhesive to attach the drywall.
While this can be more troublesome as the drywall needs to be held firmly against the wall studs while it dries, some people use this, so they don’t have to cover the nails afterward.
However, if that adhesive is not very strong, or there wasn’t enough pressure applied to the panel as it was drying, it can quickly fail, causing the panel to work away from the wall studs resulting in a malformation of the board.
Unfortunately, once it’s screwed in, it’s hard to get behind the wall to re-attach it. So you’ll usually need to remove the panel completely and reglue it.
Bees
Not exactly a common occurrence, but it is also one that’s not unheard of. Sometimes bees will get into the home through an attic and build a hive that, over time, grows and extends down behind the drywall.
As this grows, it can pressure the drywall from behind, causing it to bulge and expand.
So if you hear any buzzing behind the drywall bulge – call pest control to have them fix it.
How to fix a drywall bulge
While a good broad answer to this is always to replace the panel, we often need to consider what initially caused the problem as this may change our repair method or add additional steps that we need to perform to ensure the problem doesn’t arise again.
Here are the leading solutions you can apply to rectify a bulging drywall panel problem AFTER the underlying issue, such as a water leak, has been addressed:
1. Replace or loosen overdriven screws
Once you have identified which screws have been overdriven, you will need to remove them and the fastener completely.
Remember, this can’t simply be loosened as they will no longer be secure in the panel, and often they will have damaged the internal core of the wall making it a weak point of installation.
So once the old screw is removed, you need to fill the hole with something before you can re-screw it.
YOU SHOULD NOT USE DRYWALL FILLER as it’s not secure enough to hold a screw and is considerably weaker than the drywall itself. Drywall filler is only to fill holes from an aesthetic and looks perspective.
So we suggest using wood filler, joint compound, or something equally as strong.
2. Tighten loose screws
Fortunately, this is a bit easier to address than overtightened screws. Once you have identified the loose screws, you can retighten them with adequate pressure.
If the screw spins in place and doesn’t feel secure, you may need to remove the screw, fill the hole, and re-screw it to ensure it will hold and come loose later.
3. Replace a section of the drywall panel
Sometimes if your bulge is restricted to a small enough area and you have identified no underlying cause such as water damage, you can cut that piece of drywall out and then cut a fresh piece to replace it.
Fill the gaps with a drywall filler; by the time you’ve painted over it, you’d never know there was a bulge!
4. Replace the whole panel
This is probably the easiest solution in many scenarios, as replacing drywall isn’t that difficult, and it gives you fresh screw holes to attach the drywall to the wall studs.
In scenarios where the foundation of the home has moved slightly, or the panels were not cut to the correct size upon installation, this is the only proper method you can use.
David Kessler is a CSLB licensed contractor with over 25 years of experience. He is specialized in home building, construction, and electrical works; he also has a keen eye for interior design and, over the years, has collaborated with various architects.
