If you notice your ceiling drywall sagging, your first thought is probably that it’s very unsightly, and you should get the drywall replaced as soon as possible.
But before you go ahead and immediately start to rip the old ceiling drywall down and get it replaced, you must identify what is causing the problem beforehand. Otherwise, the problem will reoccur, and it may be a symptom of a much more severe structural issue.
So in this article, we’re going to go through 6 potential causes of ceiling sag and how to fix them so you can address the root cause of the problem and be sure that it will not come back.
Why is your ceiling sagging?
At first glance, the issue may lie with just the ceiling drywall itself, and ripping the old one out and replacing it will fix the issue. More often than not, the problem is caused by something else causing the sagging effect.
We must be cautious and identify the root cause of the problem before taking any steps to replace the ceiling. It can be triggered by anything from an improper installation to serious structural issues that may present a safety risk.
Not only that, but the longer you wait, the more prominent the sagging may become, resulting in a more serious repair job and ultimately costing you more money. So it’s essential to address this problem as soon as possible.
The first thing to establish is what precisely a sagging ceiling looks like.
It can manifest in several ways. The word ‘sagging’ is an umbrella term for any malformation of the ceiling’s usual flat shape. This can include a deep bow across the entity of the ceiling or sagging between the ceiling joists, so you get this ‘wave-like’ effect, also referred to as ‘pillowing.’
It can even manifest as significant cracks accompanied by ceiling distortion.
So let’s take a further look at what might cause sagging
1. Building foundation shifting
Both old and new homes can experience a certain degree of foundation shift, but for different reasons. A new home will have an inevitable ‘settling in’ period in which the foundation may move and settle itself over 12 months after construction is completed.
But an old home may also have a slower, more long-term shift over many years and even decades.
This shifting of the home’s foundation can exert new forces upon a ceiling causing distortion or warping of the drywall, otherwise called ‘sagging.’
It can also affect walls and floors too. So be diligent and inspect your home for cracks and visual malformations, particularly if you notice any doors suddenly becoming sticky when they were previously not – it may indicate the door frame has warped too.
Should you notice any signs of foundation shifting, the safest option is to have a building inspector check your home as soon as possible.
2. Incorrect drywall installation
Of course, not every cause of a saggy ceiling is something as serious as foundation shifting. One of the most common causes is that it was simply incorrectly installed.
Many user-based errors can be made (whether unintentional or, unfortunately, sometimes intentional) that will manifest as ceiling sagging.
These can range from the incorrect spacing of the screws. Usually, 4″ screws are used with a 12″ spacing between them. However, it’s not uncommon for the installer to want to play this rule a bit loose and place them further apart to save on screws and labor time.
Then, it starts to sag because the drywall doesn’t have enough support.
Another potential installation error is that only ½” thick drywall was used. Despite being very light and cheaper than its ⅝” counterpart, its lack of rigidity makes it prone to sagging.
Sometimes ½” works just fine, but if you have extra-large gaps between your support beams, it won’t be rigid enough and will sag. An easy solution is to replace it with thicker and more rigid drywall.
It’s also possible that the drywall panels were not cut to the correct size. If they are cut just a few mm too large, it will create pressure between the panels causing them to bow down and appears sagging.
Unfortunately, there is no singular solution to this, sometimes, you can further reinforce the drywall with extra screws, or you may have to remove the panels and trim them down to a better size.
3. Water damage and leaking
This is the problem everyone dreads. There is a multitude of ways water can make its way into the home and onto your ceiling. It could be a leaky roof, a damaged pipe, or in some rare cases, exceptionally high humidity that can adversely affect the drywall ceiling.
Regardless of how water has made its way to the ceiling, once it pools on top of the drywall, it can weaken and cause it to ripple, sag, and bulge. If left alone for long enough, the water might break through the drywall, creating a hole.
This is important to address as soon as possible because water-damaged drywall presents a safety issue.
But if water is making its way onto the ceiling, it would also be making its way into the structure of the home, which can lead to much more severe problems such as structure joist warping, wood rot, and if left unaddressed for long enough, a complete ceiling collapse.
Water damage can usually be spotted by touching the drywall and feeling any dampness or moisture. Or you can sometimes discover this with a visual inspection, such as a rippling effect on the bottom layer of drywall (kind of like when a piece of paper becomes soggy) or any discoloration caused by mold.
4. Termites and pests
Depending on your location, termites or other pests such as particular kinds of ants or even bees may need to be considered a potential issue, particularly in older homes where few steps have been taken to protect against things such as termites and other kinds of bugs.
As things like termites remove material from the supporting ceiling joist, the structure will start to weaken and bow, exerting more force on the drywall below, causing the sagging.
If you have any suspicion of a termite problem, call a local exterminator to inspect the premises as soon as possible.
Once the issue is addressed, you should also ensure your home is protected against future problems, including staining and treating all exposed wood structures.
5. Excessive vibrations and disturbances
This is certainly a less common cause, but depending on your environment may be one you need to accommodate for. Long-term exposure to vibrations can cause warping and distortion in a ceiling.
There are many potential causes, including roller garage doors creating vibration through the house or even if you live close to something like a train station.
Regardless of the cause. Small cracks and fissures will often accompany this sagging along the seams due to the pressure exerted on the ceiling.
Generally speaking, this will need an expert assessment to confirm your suspicions.
6. Age
As ceilings age, they tend to sag or bow a little. This could be due to the material becoming distorted or the fixings and adhesives becoming less effective over time.
Sometimes these can be re-affixed or repaired, or if the ceiling is already considerably old at this point and there are no other underlying root causes, you can just replace the drywall ceiling and repaint it.
How to fix a saggy ceiling
Most of the time, you will be able to replace the panel to correct the visual look of the ceiling. But it is vital to ensure that the root cause of the problem is either addressed or at least identified to ensure it won’t cause a recurrent problem.
1. Inspect for foundational shifts and repair
While ultimately, you will need to remove and replace the warped ceiling. It’s essential to identify if a foundation shift of the home was the cause of the sagging, and then furthermore, whether that foundation shift is something natural or whether it’s something that needs addressing.
Ultimately this can only be determined by a licensed contractor, but here are some telltale signs that this is the cause:
- Cracks along the walls or ceiling
- Door frames are square and uneven, resulting in sticking
- Wall frames have separated from the brick
- Tiles in the kitchen or bathroom are cracking
Once the foundational issue has been fixed, you can go ahead and fix up the ceiling.
2. Reinstall, patch, or replace
If it’s determined that there is no underlying cause of the sagging which needs addressing, you can patch/fix up the problem so it looks more aesthetically pleasing.
If cracks have formed, they can be filled, sanded, and repainted. If not enough screws and supports are used, you can add some extra support to attach it to the ceiling, or sometimes you may need to replace the panel entirely.
3. Fixing water damage
How you address water problems can vary greatly depending on where the issue originated and what kind of ceiling water damage has occurred.
The first thing to do is inspect the place to determine where the water is coming from and have that addressed.
Once the water problem is sorted, you can replace the water-damaged ceiling.
4. Exterminate pests and bugs
The first port of call here is to call an exterminator to assess the extent of the issue.
After that, make any structural ceiling repairs that need to be made due to damage from the pests, so you have a solid foundation upon which to install the new ceiling.
Then you can remove the sagging ceiling and replace it with a fresh one, secure in the knowledge there is no underlying problem.
5. Reduce vibrations and disturbances
This can be more challenging to address as sometimes we don’t have complete control over our environment, and removing the vibration sources is not always achievable.
Some additional steps can be taken to help reinforce the sagging ceiling, such as using other screws to keep everything in place, as well as extra adhesive to provide additional stability to the panels and to reduce the movement they experience during vibrations.
6. Address aging ceiling supports
Sometimes as homes age, certain areas will need to be repaired, reinforced, or replaced. Determining what area of the ceiling has aged and to what extent will decide which course of action should be taken.
Unfortunately, this is not something you should self-diagnose. Hence, we recommend hiring a trusted building inspector to ascertain the extent of the problem and advise on the best course of action to ensure your some is safe and secure.
Once you are sure that problem is addressed, replacing the sagging ceiling is just a case.
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.
