Why Does Your Wallpaper Look Bumpy?

Applying wallpaper can be tricky, even if you’re an experienced DIYer. You may think your wallpaper application was flawless… until you notice bubbles the next day. Womp womp.

What happened? And, more importantly, how can you fix it?

Your wallpaper may look bumpy because of trapped air bubbles. Other possible reasons include the wallpaper not drying properly, or you’ve applied too little or too much wallpaper paste. In addition, the underlying wall could be uneven, giving the wallpaper a bumpy appearance. 

In this article, I’ll discuss the potential reasons for your wallpaper looking bumpy and explain how to avoid such issues in the future. I’ll also offer some quick fixes to get rid of the air bubbles once the wallpaper has already dried.

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Do you have bumps or bubbles in your wallpaper? Don't worry, you're not alone! Learn what causes wallpaper bubbles and how to fix them with this easy guide. Say goodbye to bumpy wallpaper and hello to smooth, flawless walls.

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1. Trapped Air Between the Wallpaper and the Wall

One of the most common reasons wallpaper looks bumpy is trapped air underneath.  

If you’ve worked with wallpaper before, you know how important it is to go over it firmly and thoroughly with a wallpaper smoother to make it stick better. However, sometimes an air bubble can escape your notice, or you just fail to entirely remove the excess air in the space between the wall and wallpaper.

This is especially true with peel-and-stick wallpaper (my personal favorite). These are my favorite peel-and-stick wallpapers from Etsy if you’re looking for stylish options!

This process requires a lot of concentration, so don’t be upset with yourself if you miss an air bubble or two. Practice makes perfect, and the more you work with wallpaper, the better you’ll get at eliminating the issue from the beginning.

How To Fix

If the bumps on your wallpaper are small and can be fixed with a small amount of paste, you can remove them using a wallpaper syringe. This tool is designed exactly for this purpose and can be found on Amazon or at any hardware store or a local craft shop.

It’s best to look for a syringe with a solid metal needle, as you want it to pierce the wallpaper as neatly as possible. Only a top-quality tool can do a clean job with this, especially if your wallpaper is thick.

Here’s what you need to do:

  1. Fill the syringe with adhesive. You may need to thin the adhesive a bit so it flows easily through the tip.
  2. Use the syringe to place the paste under the bubble and allow it to soak.
  3. Once the wallpaper has absorbed the adhesive, use your fingers to smooth the bubble out.

If a bubble is too big to be dealt with in one injection, you can try an alternative method of applying the paste. Here’s how to do it:

  1. Use an X-acto knife, a craft knife, or similar to cut the bump on your wallpaper in the shape of a cross.
  2. Apply adhesive to the four pieces of the cross and leave them to soak.
  3. When enough time passes, smooth the cross with your fingers.

2. You’ve Used the Incorrect Amount of Wallpaper Adhesive

Another reason might be the amount of paste you used. Applying too much or too little of it can cause issues with the wallpaper sticking properly, which leads to air bubbles appearing on your walls.

The trick is to cover the surface of the wallpaper with paste evenly, but make sure the layer is thin, just enough for the material to bond with the wall. It can be tricky to get that right from the first try, which is why an improper amount of adhesive applied often causes your wallpaper to look bumpy.

If you apply too much adhesive, the wallpaper will become too moist and unable to adhere to the underlying surface effectively. It’s also common for the excess paste to clump up once it dries, creating bumps that look like air bubbles.

Too little paste, on the other hand, means that the wallpaper wasn’t correctly covered with adhesive, and the spots you missed simply didn’t bond with the wall. This also creates an uneven, bumpy look.

How To Fix

You can easily find the sections where too little adhesive was used because they will look loose. Here’s how to fix these sections: 

  1. Using a razor or sharp knife, carefully cut an opening in the wallpaper to give you access to the unglued section. 
  2. Apply some adhesive with a wallpaper syringe and gently press the wallpaper down. 

If you suspect the bumps in your wallpaper are due to using excessive adhesive, cut an opening in the wallpaper, gently remove the excess glue with a craft knife, and use some adhesive to attach the wallpaper again. 

3. You Didn’t Allow Enough Soaking Time

Bumps in your wallpaper could also be because you didn’t let the wallpaper soak properly.

The amount of soaking time for wallpaper depends on the brand and wallpaper type, and it’s important to follow the instructions on the packaging because wallpaper stretches and expands when it comes into contact with liquid, such as wallpaper glue. 

Allowing the wallpaper to soak gives it time to react to the liquid you just applied so that it won’t change in size as you smooth it out. If this step is skipped, or you don’t wait long enough, it will inevitably cause issues with the wallpaper sticking.

As a result, air bubbles appear, and the wallpaper looks bumpy. The best way to avoid such problems is to wait patiently until the wallpaper absorbs the adhesive and only then apply it to the wall.

How To Fix

If your wallpaper looks uneven or bumpy because you didn’t allow enough soaking time, you may need to remove it completely and reapply it if the bumps are severe and widespread. However, you can smooth out small bumps using a wallpaper syringe and some adhesive. 

4. The Wallpaper Hasn’t Dried Properly

The conditions in which the wallpaper dries also impact how effectively it adheres. If it doesn’t dry properly, it can end up looking bumpy and even start to peel off.

How To Fix

It is important to minimize humidity in the room as wallpaper dries. It’s also best to keep the room slightly cooler than the average temperature but not lower than 50°F (10°C). High humidity will continually influence the paper making it hard for it to stick, and so will the temperature if it’s too high or, on the other hand, too low.

How do you maintain the most suitable conditions for the wallpaper to dry? Your best bet would be to ventilate the room regularly. However, excessive ventilation also won’t be good for ensuring the wallpaper holds.

Try ventilating the room at equal intervals for about 10 minutes. Check temperature and humidity to ensure the conditions are as required. This simple technique will allow you to avoid bumpy wallpaper in the future.

5. The Underlying Wall Is Uneven

Finally, the problem could be caused by the wall’s underlying surface. For the wallpaper to adhere, the wall should be prepared in advance. If you’ve skipped this step, this is likely why your wallpaper looks bumpy.

The surface must be flat for the wallpaper to look smooth and even. To achieve that, you should start with mudding. This process entails evening the wall’s texture out with joint compound. You must apply a thin layer in problematic areas and then sand it.

Secondly, if there’s residue from the previously stripped wallpaper, it will also get in the way of two materials bonding and cause air bubbles. Make sure the wall is completely clean before applying wallpaper.

Lastly, the wall should be completely dry for the wallpaper to stick. If the surface is moist, it won’t bond with the paper, and you will surely have to deal with bumps later on.

Some of these factors make painted walls look bumpy, as well. Check out my article to learn about other causes and how you can prevent them!

How To Fix

How you resolve an uneven wall surface depends on how bad the wallpaper application is. If only a small section looks messy, you can fix this with a wallpaper syringe. If not, you’ll need to remove the wallpaper and smooth out the underlying wall before reapplying it. 

Final Thoughts

There are several possible reasons for your wallpaper to look bumpy. It could be that some air remained between the wall and the wallpaper, the wall’s surface wasn’t prepared properly, you didn’t give it enough time to soak, or there was too much or too little paste used. 

The bubbles can be removed by adding more paste using a wallpaper syringe or by cutting the bump in a cross shape if it’s large.