How To Fill The Gap Between A Ceiling And Wall [Step By Step Guide]

The gap between a home's ceiling and the wall is often overlooked. Yet it can become a source of severe problems if ignored and not addressed. Keeping this in mind, you might wonder how to fill the gap between a ceiling and a wall. We researched this topic, and here is what we found.

To fill the gap between a ceiling and a wall, you can take these steps:

  1. Prepare the area and all the materials needed
  2. Apply expanding foam
  3. Apply gypsum plaster
  4. Sand
  5. Paint

Keep reading as we lay out more details on these steps. We also tackle other related topics, such as the common causes of the gap, why filling the gap is essential, and the various types of filler used to fill the gap between a ceiling and a wall.

A handyman applies putty or filler to cover the gap between a wood cornice and a concrete wall, How To Fill The Gap Between A Ceiling And Wall [Step By Step Guide]

How To Fill The Gap Between A Ceiling And Wall?

It is typical to have a 1-inch gap between the ceiling and the wall in your home. However, a gap that measures 2-inches or more can cause problems.

Below is the step-by-step guide on how to fill the gap between a ceiling and a wall in your home:

1. Prepare The Area And All The Materials Needed

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Plastering instruments tools and materials for room renovation against weathered wall

Before starting the filling job, prepare the area and all the materials needed. Keep the site clean and free from any obstructions. Also, wear personal protective equipment such as gloves if necessary.

Other than the filler, the tools and materials you need include but are not limited to:

  • Twin step or platform ladder
  • Putty knife
  • Plastering trowel
  • Sandpaper
  • Straight edge brush
  • Paint

2. Apply Expanding Foam

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Big hole in a wall and a expanding foam for repair

If there is a considerable gap between the ceiling and the wall, you can use expanding foam to fill it.

Regardless of the expanding foam brand you choose, please carefully read the instructions on how to use it properly.

Here is a general guideline:

  1. Moisten the gap you intend to fill using a brush or a spray before applying expanding foam.
  2. Use the applicator nozzle to apply the expanding foam throughout the hole. Remember not to overfill the gap since the expanding foam expands.
  3. Wait for the expanding foam to dry.
  4. Once dry, use a putty knife to cut the excess material.

See this expanding foam on Amazon.

3. Apply Gypsum Plaster

After trimming the excess expanding foam, use a putty knife to apply gypsum plaster along the gap. To get an even surface, you can use a plastering trowel to spread the gypsum plaster.

Wait for the gypsum plaster to dry.

Hand worker spreading plaster with trowel to gypsum board

4. Sand

Once the gypsum plaster dries, sand the area using sandpaper to make it smooth. Don't forget to wipe the surface lightly using a clean cloth to remove the powder generated by sanding.

Sanding your ceiling

5. Paint

After sanding, use a paintbrush to paint the area to match the ceiling and wall colors. Apply a second coat if needed. Please ensure that the joint compound or drywall is completely dry before painting.

White paint and a black brush prepaired

Painting helps conceal your work and makes the gap between the ceiling and wall unnoticeable.

See the entire process in action here:

What Are The Common Causes Of A Gap Between The Ceiling And The Wall?

The gap between a ceiling and a wall arises from the reasons discussed in this section.

Truss Uplift

Truss uplift occurs when the bottom chord of the truss is exposed to temperatures or moisture levels that are significantly different from that of the remaining truss members.

For instance, the bottom chord can shrink as the warm temperature from the ceiling keeps it dry. Meanwhile, the upper chords expand as they absorb moisture and are kept damp by increasing humidity.

Due to this difference in movement between the top and bottom chords, the truss arches up in the center. When this happens, the trusses pull away from the top plates at the intersection between the ceiling and the wall.

The plates run perpendicular to the direction of the roof trusses. Consequently, the joint tape splits when they pull away, creating a gap between the ceiling and the wall.

Poor Construction

A gap can develop between the ceiling and the wall due to poor construction. To be specific, the lack of precision during installation and improper finishing of the wall.

Drywall taping is an essential part of finishing.

So, if the wall joints are improperly taped, such as using an insufficient amount of joint compound when applying the drywall tape, its separation from the ceiling is most likely.

Foundation Settling

After the construction is finished and over time, all foundations tend to settle to some degree. The settling can range from average to severe, depending on the soil beneath.

Moreover, the local climate and natural events also influence foundation settling.

The cracks or gaps between the ceiling and wall may result from the foundation settling's effect on the frames, shifting pressure levels.


Suppose ongoing construction activities in your area use heavy machinery for soil compaction or drilling for concrete roads.

In that case, they can create vibrations of sufficient strength that can cause a crack or noticeable gap between the ceiling and wall.

Vibrations can also come from heavy equipment if a factory is nearby or from natural calamities such as an earthquake.

Why Is It Important To Fill The Gap Between A Ceiling And Wall?

A gap between the ceiling and wall makes the edges look messy, unprofessionally done, and unfinished. So, filling this gap is needful, especially if you intend to sell the property.

By filling the gap, you make the property more presentable, thus increasing the chances of selling it at a high resale value.

Aside from that, it is essential to fill the gap to minimize the chance of dust or insects getting into your home and causing health and sanitation problems.

Sealing the gap also reduces the risk of moisture damage to structures such as walls and ceilings.

Furthermore, it is a proactive measure to keep your electrical wiring and electronic appliances free from moisture contact. The hole can be a source of moisture if left unattended.

When you ignore a sizeable gap between the ceiling and the wall, the worst-case scenario is that your home can collapse when triggered by strong vibrations from machines or an earthquake.

What Are The Various Types Of Filler Used To Fill The Gap Between A Ceiling And The Wall?

The ideal filler to seal the gap between a ceiling and wall depends on the material the ceiling and wall are made of and the gap's size, length, and depth.

Here are some of the most common fillers used for a gap between a ceiling and a wall:

Joint Compound

A joint compound is called "drywall mud" or simply "mud."

It is a glue derived from pulverized gypsum that holds drywall tape and drywall in place while covering any screws, seams, or joints before painting the surface. Usually, it is pre-mixed or in powder form.

Both powdered and pre-mixed joint compounds often contain additives that help the mud become smoother and more moisture-resistant.

A joint compound is one of the most common materials to fill the gap between a ceiling and a wall. You apply this product to the hole using a piece of paper called joint paper.

Apply as many layers as necessary to fill the gap.

Check out this joint compound on Amazon.

Spackling Paste

Spackling paste, often known as spackle, is a putty made of gypsum and binding agents. You can use it to fill minor holes or cracks in a surface before painting.

The paste is similar to a joint compound and accomplishes the same objective: covering cracks or gaps in walls and ceilings. However, spackling paste is designed for tiny repairs, dries more quickly, and shrinks less when drying.

Because it is simple to use, spackling paste is especially preferred when there is only a tiny gap between a ceiling and a wall.

See this spackling paste on Amazon.

Expanding Foam

Expanding foam, sometimes called insulation foam or spray foam, is a polyurethane or isocyanate contained in a can. It offers airtight insulation around materials, joints, and other components.

The foam filler can seal cracks or gaps between the ceiling and wall and holes around fittings. This sealant provides a barrier that keeps air, moisture, and insects from entering gaps.

Generally, you spray the foam on the surface through a nozzle. Although the foam is a thin liquid, when you spray it, it hardens and expands 30 to 60 times its original size depending on the type.

Gypsum Plaster

Gypsum plaster is made of gypsum mineral that is wholly or partially dehydrated. The plaster is white and is sold in powder form.

To create a ready-to-use paste, mix the powder with enough water. You can then easily apply the mixture to the gap between the ceiling and wall surfaces. It produces a smooth finish, a level surface, and superbly right-angled corners.

The plaster is effective as a thermal insulator and is fire-resistant.

Furthermore, it doesn't shrink while setting; therefore, there are no cracks. However, this plaster is only appropriate for inside use; you cannot use it for external plastering.

In Conclusion

A handyman applies putty or filler to cover the gap between a wood cornice and a concrete wall

There are several causes of a gap between a ceiling and a wall in your home.

But whatever the reason, it is essential not to ignore this gap - fill it as soon as possible. We hope the simple steps we have outlined will guide you as you fill the gap.

If you found this helpful, do check out our other related articles:

6 Best Wood Fillers For Large Gaps

How To Fill Large Gaps In Your Foundation?

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