Why do you get blisters in drywall mud (and what to do) | hooked (2022)

Drywall grout (mix) is used for virtually any drywall repair. For the most part, its ease of use makes it easy and effective to work with. However, there is one problem that persists when dealing with drywall mud, which is blistering. These can be frustrating and difficult to remove, so let's see how to do it.

You will get bubbles in the drywall mud because it is a porous compound. That means air can flow through it. In cases where theDrywall cannot absorb air from the mud in the drywall, the air is displaced by the mud; Other examples of bubbles occur with drywall mud and duct tape.due to fluctuating temperatures and insufficient adhesion.

Click for the best drywall mudhere.

This article will briefly explain what drywall mud (compound) is and with that we will look at the different types of bubbles that appear in drywall mud and why they occur. Next, let's take a look at a detailed solution to solving the drywall blistering problem that plagues many handymen.

Understanding Drywall Mud

To better understand why drywall mud blister when the mud is applied, it is beneficial for us to first understand what drywall mud is. Then we can understand why this phenomenon occurs.

Drywall grout is actually a type of joint compound used to reinforce and smooth drywall and joints. There are two kinds; one comes in aSpray(dry) form that you yourself will mix, and the other ispremixed mud. The latter is purchased ready-made and you can start using it right away. There are different types of drywall mud that have different cure times (a set amount of time it takes to dry) and come with multiple fire resistance ratings.

It is important to note that the fire rating of these products is tested as a component of the system as a whole and not as individual elements.

No matter what drywall compound (mud) you use, there's always a chance it will bubble, and that's because mud is mixed with water and therefore inherently very porous (has spaces, so air or water can leak in).


Why do you get blisters in the mud on the drywall?

There will be two main reasons why you get blisters on your skinDrywall mud and the first reason is because of the paint on the drywall and the other reason is because of the drywall tape. Let us look at these two factors, explain why they occur, and then give you workable solutions to resolve this issue.

Bubbles on painted drywall

Initially we said that drywall mud is porous and isdrywall(Food plates) This means that it has small spaces in the middle that allow it to take in air and water. So when the drywall compound is spread over it, those tiny gaps (holes) in the drywall suck air out of the drywall grout. Because of this, you constantly find that when you apply mud to clean drywall, there are usually no bubbles, which is great.

The problem arises and persists when the drywall is painted. It's even trickier, depending on the color and type of finish (paint with a high gloss finish usually causes the most problems). Because the paint covers the drywall, the drywall loses its permeability (it is no longer porous).

Keep in mind that most paints are waterproof and repel water. Imagine if paint wasn't like that, the interior wood beams in your home would need to be replaced on a regular basis.

Since the drywall can no longer absorb the mud due to the paint, the air has to escape somewhere while the mud hardens. The only other direction the air can move is in the opposite direction of the paint, so bubbles form.

What to do with bubbles in drywall with paint

There is no easy fix for this solution and it will take some round trip time. There is usually no way to get rid of blisters by applying two coats of mud. The minimum number of coats typically required to eliminate blisters on an area of ​​painted drywall is three coats or more.

What you should do is first cover the area in question with mud and work with it a few times as usual. Then look for bubbles in the colored sections behind them. If you're lucky and don't find any bubbles, you're lucky and continue as usual; However, you will most likely find some in the colored areas, so you will need to scan the room closely.

This means you use your knife orWhoat a 45 degree angle and try to fill any gaps, holes or cracks and remove bubbles. To do this, walk over the area several times, brushing as close to the drywall as possible. Plus, you'll be doing this in a variety of directions, including side to side and top to bottom.

(Video) How To Fix Drywall Tape Bubbles

Once this is complete, the wall can be left nice and smooth; However, you can still see the grout in the area which will become apparent if you go ahead and let it sit and then continue painting it. This is not optimal and the debubbling process is not yet complete.

Once you have applied the first layer and removed it as firmly as possible, you should apply the next layer of mud. Depending on the compound you have, the cure time will be different. In some cases, it would be best to let the mud sit for 3-5 minutes before applying the second coat so as not to disturb the initial coat that skimmed off well.

This coat is applied as you would normally apply a regular coat of Compound and will do everything as usual, including smoothing out the edges. You'll then complete your second coat of paint with a couple of finishing passes, and what you're trying to accomplish with this is to try to leave about 1/16 to 3/32 of an inch of mud on the drywall.

Next, let the area sit for about 3-5 minutes to see if it blisters through the second coat. At this point, there should be no or very few bubbles left in the drywall. Now let the compound harden and then lightly sand.

It is important to note that the medium grainSandpapershould be used because you don't want to take too much off the wall; Otherwise, you may wipe out your hard work and have to start over. The point here is to gently sand down any bubbles that may appear.

The final step is to apply the third coat of compound in the same manner that you applied the second coat. You will apply it as usual, moving across the areas with long strokes and feathering the edges, leaving about 1/16 inch of your last layer on top of the previous layers.

After letting the third coat sit for about 3-5 minutes, you should examine the drywall and find no bubbles. You can then let it heal properly and move on to the next part of the renovation. If you would like a visual guide walking through this process step by step, be sure to check out this videohere.

Bubbles on Drywall Tape

The next time you will notice bubbles is when using drywall tape.drywall tapeused to hide joints where drywall sheets meet. Generally, the procedure for placing theDuct tape on a drywallthe joint has no complications.


First fill the joint over the entire area with putty and apply it evenly and smoothly. Then take a piece of duct tape (there are two types that affect blisters, which we'll talk about) and apply it to the hinge area. Take your paddle, then run the tape through and press it firmly into the mud. After that, make another pass in the area with more compound, seal the tape and smooth the edges, making the adhered drywall area invisible.

As stated, there are two types of tapes. One variant is designed with a net-like structure, which is great as it allows the tape to adhere without bubbles. The next type of tape (paper tape) is solid, and you usually have a problem with that tape.

There are two reasons why this paper tape will not stick to the underlying drywall initially and will cause blisters. One of the reasons is that it was never safe in the first place and just cuts off from the area. The other is the temperature.

The temperature of the tape will be slightly different than the drywall as the underlying mud and compound on top begin to harden. Due to this temperature change, it eventually comes off the drywall.

What to do about bubbles in drywall tape

In most cases this is not a problem because if you have applied the tape correctly, flattened it, and pushed it down into the initial layer of mud, there should only be a few burrs at the edges of the wall that are peeling away. of the tape and causing blisters

Keep in mind that no matter how many times you coat the compound, this problem persists and must be resolved in one of two ways.

If the area is large (about 2 feet or more), then it would be beneficial and in your best interest to remove that section of tape and start over. Again, make sure your first layer isn't too thick and that after you've applied the tape along your hem, go over it with your trowel and press down firmly, sliding it over the tape. You need to make sure to embed the tape into the mud during this process. Go over the area with your trowel, the widest edge stroking it nice and steady. Once this is done, apply the top coat of compound over the tape. Look at this videohereif you need a visual aid for this particular process.

At this point, the second problem may arise. This problem occurs when the tape peels away from the wall, leaving only small grooves along the edge of the tape. If you are facing this problem, the solution is quite simple. As long as the section of tape you peeled off the wall does not go past the seam, all you need to do is take an Xacto knife (utility knife) and cut that section of tape, leaving the rest intact. Carefully remove the cut out section of tape.

(Video) How to fix drywall tape bubbles

They would then go over that area and apply mud and fill in that space. As long as the cut out section is not large, the dough should fill the area well and there will be no visible edges.

In some cases, you may see a color difference in the area where you removed the tape and filled with compound. You may also notice that this area is slightly indented. You don't need to worry about this because when you apply your second or third coat, that section will be covered and no discoloration or indentation will be visible in the area.

In cases where the tape is peeling away from the drywall along the seam, but the affected section is still relatively small, reuse yourutility knifeand cut that section stopping at the point where the tape will adhere firmly to the drywall.

Keep in mind that if you leave sections of the tape that don't adhere properly to the seam, it may and will tear over time. So cut this piece of tape with your utility knife and get another section of tape that is the samesize as required area, and place it in this area as usual. Also, this problem can occur at drywall edges, but it can also occur in any area of ​​the seam where the tape is not adhering properly. The same repair principle applies to all cases, as long as the section in question is not too large.

If you need a visual aid to understand what we have described here, take a look atIt's videowhere drywall blister repair in relation to duct tape is explained and repaired.

final thoughts

Understanding drywall sludge is the first step in determining why bubbles appear in drywall materials and how to resolve them. We found that the mud is porous, which means it lets air through and can cause bubbles to form.

The first reason blisters form is when your drywall has a coat of paint on it and the repair involves covering that area of ​​paint with mud. Because paint is non-porous and drywall doesn't allow air to breathe, the mud forces the air out and creates bubbles. The solution to this is to firmly skim each layer of mud, allow it to harden and sand, and repeat the process until the bubbles are gone.

The next form of mud blisters on drywall occurs with drywall tape, where the tape does not adhere properly to the adjacent drywall seam. This causes blisters at the edges and, in some cases, at the hem.

(Video) Novices- NO MORE DRYWALL BLISTERS? Tape with Paper Tape with ease

Depending on the size of each bubbly section, you may need to remove the entire length of the tape and start over, or if the sections are small enough, you may just need to cut them off with your Xacto knife (utility knife). Then place another piece of tape on that section and go over it with the drywall compound.

The last thing to remember is that while this may seem like a simple repair job, you need to be careful as the pressure exerted by trying to smear mud firmly against the drywall can damage your rotator cuffs. Stay alert, try to sand the painted areas first and tape correctly.


How do you deal with bubbles in drywall paper? ›

Scrape off the bubbles with a 4-inch drywall knife. Try not to gouge the walls, but make sure to get all the loose material off. Then it's time to patch.

What causes drywall blisters? ›

We believe that the blisters are formed with air that escapes from tiny fissures or cracks in the skim coated wall below the layers of applied paint. Under low humidity drying conditions, drywall mud and skim coat will shrink to such an extent that tiny cracks will form on the surface.

Why is my drywall tape blistering? ›

There's only one main reason for bubbles appearing below the drywall tape and that's poor installation. The joint compound has not been properly embedded on the tape and hence bubbles form. Most people will try and cover the bubbles by applying a fresh coat of compound.

Why do you put Dawn dish soap in drywall mud? ›

Dish detergent makes the mud go on really smooth - it acts a s a surfactant. This trick is usually employed by folks who will NOT be painting the finished walls as sometimes the addition of dish detergent causes paint adhesion problems.

Why are there so many bubbles in drywall mud? ›

When applying drywall mud to a previously painted surface, using too thick a layer or not properly scraping it can also add air to the drywall mud and cause bubbles. If you mix drywall mud incorrectly, it can also cause bubbles because overmixing can add in pockets of air.

Should you pop wall bubbles? ›

The best preventative measure is pop the bubble. This will get the water away from the drywall and lessen the amount of overall interior damage to your house. All you need is something to catch the water and something sharp to pierce the layer of paint.

How do you fix blisters on plaster? ›

As moisture seeps through a wall, it can push your plaster forward, causing a small bubble in the material known as blistering. The only effective method of removing the blister, after dealing with the moisture issue, is to remove the effected plaster and replace it with a patch.

What is the most common cause for paint blistering? ›

Paint blisters or bubbles occur when the paint film lifts from the underlying surface. The loss of adhesion between the paint film and surface is usually caused by heat, moisture or a combination of both.

What is the difference between sheetrock mud and joint compound? ›

Joint compound is the same as drywall mud or just mud. It's comprised mainly of gypsum and limestone, but it also has other materials such as clay, mica, perlite, and starch. Joint compound has a spreadable consistency similar to mud, which is how it got its common name.

Do you need 3 coats of drywall mud? ›

If your wall has distinct crevices, cracks, or textured areas, or if your brand of drywall mud isn't offering enough coverage, you may have to do a couple of additional coats of compound. However, in general, you'll need one coat to fill in the seams and three more coats after taping.

Should I add water to my drywall mud? ›

Do I need to add water when mixing Sheetrock® Brand UltraLightweight All Purpose Joint Compound? No, Sheetrock® Brand UltraLightweight All Purpose Joint Compound is formulated as a ready-to-use product. Simply mix and use. If adding water, use sparingly and test apply.

Does toothpaste work on drywall? ›

Use Toothpaste to Fill Holes. Toothpaste is a great alternative to spackling if you have a hole in your wall smaller than 1/4 inch. Try to find a toothpaste close to the color of the wall, then squeeze the paste into the hole and wipe off the excess with a putty knife or playing card.

Do I need to prime drywall patch before painting? ›

Patches made with traditional patching materials need to be primed with a sealing-type primer before painting. Otherwise the patched areas could show through the finished paint job as foggy spots. But if you patch with a self-priming patching material, you can avoid this extra step.

How smooth does drywall mud need to be before painting? ›

Using firm pressure, go over the area with your knife until there is only a very thin smooth layer of mud over the entire area. You want to see very few ridges or bumps in the mud, and the tape should be visible through the mud. Now you need to let it dry.

What grit sandpaper is best for drywall mud? ›

Use 220-grit sandpaper and sand the areas with a light and easy touch. Avoid using coarse sandpaper below 100 grit as that may damage the drywall.

What is the reason bubbles appear in compound after it has been applied to the walls or ceilings? ›

Paint bubbling, sometimes called blistering, happens when paint loses its adhesion to the surface beneath. That surface might be the coat of paint under the one you applied, or the substrate, like drywall, plaster or wood.

Why are there bumps in my drywall? ›

Loose or Missing Screws

When installers fail to drive screws completely into the wall, the drywall won't fit tight to the framing, resulting in bulges or bumps. To fix this problem, remove the offending screw and drive a new drywall screw into the wall roughly 1 1/2 inches away on each side of the old screw.

Can I rinse drywall mud in the sink? ›

Years too late, but spackle, mud, and drywall compound will indeed settle in your pipes and clog the drain line. Don't clean your tools in the sink, and do the brunt of your personal cleaning outdoors. Save this answer.

Should I wet drywall tape? ›

Dampen, but don't soak, the tape in a bucket of water. Wetting the tape before you embed it in the joint compound can help eliminate troublesome bubbles that show up after the joint dries. Keep a bucket of water nearby and quickly run each piece of tape through it before applying the tape to the wall.

Will paint blisters go away? ›

Not all paint bubbles need to be repaired. Ace Paints, a company in Pittsburgh, Pennsylvania, says some bubbles may appear soon after painting but go down once the paint has dried. Paint bubbles can be removed by simply scraping them away from the wall. A paint scraper or putty knife is suitable for this purpose.

How can you tell if there is moisture in a wall? ›

Here are a few common signs that you have too much moisture in your home:
  1. Peeling paint or wallpaper.
  2. Water marks or staining.
  3. Wet spots on the wall or ceiling after rain.
  4. Water running down inside walls.
  5. Walls that feel damp to the touch.
  6. Visible mold.
  7. A musty, stale odor.

What does water damaged drywall look like? ›

Flaking or Peeling Paint

Similar to ceiling and wall stains, peeling or flaking paint is a major tell that your home is experiencing water damage. When your drywall is exposed to excess moisture, the moisture will try to escape through the wall or ceiling, which in turn will cause the paint to lift off its surface.

How do you smooth out a bump on drywall? ›

Use a 6-inch drywall knife to spread drywall joint compound across the patch and tape to create a smooth, flat surface. Let the compound dry overnight, then sand until smooth. Repeat with a second coat.

How do you fix a bubbled wall? ›

Bubbles are usually localized in one spot, so you only need to remove the blistering area and not any of the rest of the paint. Rub the area underneath the bubble with sandpaper to smooth the surface. If the resulting surface is pitted or uneven, apply joint compound to repair the wall.

Why is my newly painted wall blistering? ›

Paint blisters or bubbles occur when the paint film lifts from the underlying surface. The loss of adhesion between the paint film and surface is usually caused by heat, moisture or a combination of both. This condition eventually leads to peeling.

Why is my drywall mud lumpy? ›

Lumping of Mix

It happens when the initial mix contains too much water. To avoid this start by mixing with small amounts of water and keep adding water until you can see there are no more lumps in the drywall texture. Mix thoroughly and use the right mixer to do this work.

Can I sand out bubbles in drywall? ›

If you don't notice bubbles in your drywall tape until after you've painted a room, you can still use the steps in this article to fix the problem. To make the fix easy, sand the paint off the area where the air bubble is present. Then, chip away the hardened joint compound using a putty knife or scraper.

Why is my skim coat bubbling? ›

Bubbling (or sometimes called “blistering”) happens when the paper layers in the drywall become separated. While it may not seem like it's loose, you may find out differently once you slap your first layer of joint compound on the wall.

How do I stop my plaster from blistering? ›

Things You'll Need

As moisture seeps through a wall, it can push your plaster forward, causing a small bubble in the material known as blistering. The only effective method of removing the blister, after dealing with the moisture issue, is to remove the effected plaster and replace it with a patch.

What are plaster blisters? ›

Abstract. Background: Blister plasters are non-invasive and non-sterile dressings composed of a hydrocolloid layer held in place by a polyurethane film and a non-touch foil that provides an ideal healing environment.

How do you get a plaster blister off? ›

Q1: How do I take my plaster off? A: Grab one end and pull it parallel with the skin surface – like it's an elastic band and you're trying to stretch it out as long as it can get. To remove, loosen one edge and pull the plaster parallel to the skin surface – like you're trying to elongate it.

Can humidity cause paint bubbles? ›

Moisture. Moisture from water droplets, leaks, or high humidity, can all soak into the wall, creating bubbles between the wall and the paint. These types of bubbles happen in rooms where dampness is common, like bathrooms and kitchens.

Why do my walls look bumpy after painting? ›

They are often caused by a painter putting a second coat of paint on the wall before the first coat has completely dried. Using these techniques will allow you to fix stippling paint or to repair roller marks on a painted wall: Make sure the paint is completely dry.

Does paint bubbling mean water damage? ›

Bubbling occurs when water collects behind your paint and pools, stretching the paint on the surface. Finding this type of water damage is straightforward, but there's no indication of how much wall water damage has occurred behind the scenes.


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5. How to fix a BLISTER in a CORNER BEAD!!!
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6. How to Remove Air Bubbles in Drywall Mud (without No-Pocks)

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