Apart from having a negative impact on the overall appearance of a room, gaps between baseboards and the floor could be a source of heat loss and might serve as an ideal living space for insects. Gaps occur due to a variety of reasons. These may be minor issues, like a badly cut baseboard, or worse, it could be the result of serious structural problems.
In this article, I explain the major causes of the gaps between your floor and baseboard, how to tell if it is due to structural defects, and how you can cover these gaps.
Baseboard gaps aren’t functional, i.e., they shouldn’t be there. But they are common and may not indicate anything more serious than uneven floors or carpet removal. There are cases where gaps aren’t normal. Poorly built floors that sag or slope and unevenly cut or installed baseboards can create a gap.
Gap Is Probably Normal

For the most part, gaps between the baseboards and the floor are normal. I wouldn’t say that you should have gaps, i.e., they are not functional, but they are not necessarily a sign of serious defects.
They may indicate slight imperfections in the way that the house has been built or how they have been altered or how they have moved and settled with age, but even these are nothing you should lose sleep over.
Floors Are Not Always Even
Uneven floors are a common occurrence in many homes, especially older buildings.
A popular misconception is that it is always due to structural damage. However, there are non-structural factors that can affect the evenness of a floor and some of them include:
- The flooring material.
- The type of subflooring used.
- The architectural layout of the building.
Apart from these factors, the age of a building plays a huge role in the floor’s evenness. Changes in soil conditions often cause foundations to shift over time, resulting in movement of the floor and ceiling.
If the movement causes the floor to sink, a gap might appear between the baseboard and floor because the board is attached to a particular spot on the wall and cannot move to accommodate the changes in the floor level.
May Indicate Carpet Was Once Installed
If you recently moved into an apartment and notice gaps between the baseboards and floor, then it could be a clear indication that a carpet used to be in place. This is especially true if the gaps have a consistent dimension.
For a clean finish, carpets are usually tucked underneath baseboards. So, if the carpet is eventually removed, they’d be a gap where it used to be.
If the baseboard is installed before the carpet, it is common practice to leave a gap to match the size of the carpet you intend to install before attaching the baseboard.
The size of this type of gap would depend on the thickness of the carpet that was installed. The thicker the carpet’s padding, the wider the opening.
Gap Can Indicate Problem or Poor Design
While gaps in between floor and baseboard are, for the most part normal, they can sometimes indicate structural defects. They could also result from poor craftsmanship on the part of the contractor responsible for building the floor.

Sagging Floor
Sagging floors are not always perceptible. The floor might be sloping, signifying serious issues, or it could sink only in certain parts of the room.
If the floor sags around the wall, the baseboard would most likely disjoint from the floor, resulting in a gap.
The major causes of sagging floors include:
- Water damage: This could be because of leaky pipes, poor drainage, or inadequate protection against groundwater. If left unattended, it would damage joists and subflooring, especially those made with wood.
- Poorly constructed subflooring: If the subflooring is constructed with inferior materials, it would buckle in no time. Also, if the joists are not fitted correctly, it could cause the floor to be uneven.
- Foundational movement: This could result from soil movement, badly built foundation, or water damage.
- Foundation settling and joists sagging with age.
Badly Cut Baseboard
The gap might be because the baseboard itself is uneven. This can happen if it is badly cut such that some parts are wider than others or if there are indentations along the length of the wood.
If this happens, when the baseboard is installed on the wall, there would be gaps to match the irregularities in the wood. The size of the gap might vary from one point to the other, depending on the cut of the wood.
If the gap between your floor and baseboard is due to a badly cut baseboard then you’re in luck because you can fix the fault without worrying about underlying structural issues that might cause the gap to reappear or worse, threaten the structural integrity of your home.
Good or Bad Gap: How to Tell?
Sometimes gaps are harmless aesthetic flaws that can easily be covered and other times they could be a sign of structural issues. The key is knowing how to tell if your gap is innocuous or sinister.
If the gap is due to a previously installed carpet, you will notice that the openings have a defined proportion, and even if there are disparities in the size of the gap, it would be minute. You may also notice marks on the floor under the baseboard where the carpet had been secured.
Gaps that are caused by badly cut or ineptly installed baseboards are easy to spot. You’d have to take a close look at your baseboard and, if you notice irregularities in the board wherever there is a gap, then the problem is most likely from your baseboard.
You can also bring out the measuring tape and measure the width of the board at intervals to see if they match.
To determine if the opening is due to a sagging floor, examine the floor for recessed areas. You can expand your inspection a couple of feet away from the gap so that you’d notice if there is a slope in the flooring or if the floor is uneven in other areas as well. Get a marble and see how it rolls on the floor.
Most time, gaps that are caused by structural issues are accompanied by cracks in the floor and walls.
A common sign of warped subflooring is that your floor would make squeaky sounds whenever you walk across it. If you experience this, then your floor joists might need a repair or replacement.
How to Fix Gap

Air sealing the gaps in your baseboards is important for temperature control and energy-efficiency of your home. But you do not need to contact a professional to close the gaps for you. There are affordable DIY-friendly options that you can choose from.
However, if the gap is due to structural damage, covering the opening would merely be a temporary cosmetic fix. If the underlying problem isn’t dealt with, the gaps will reappear in the future and the damage will worsen over time.
Fill with Caulk
If the gap is less than 1/4“, you can cover it up with caulk. Though it is more expensive than regular acrylic latex caulk (amazon link), siliconized acrylic latex caulks (amazon link) are a better fix for gaps because they adhere better to the joints and last for a longer period.
Before you apply caulk to the gap, you should first remove dried paint from the space with a putty knife. This way, the caulk would adhere to the surface better.
If you would like to paint over the caulk, ensure that the product you purchase is paintable.
Install Molding
If the gap is too big to be covered with caulk or if it is uneven, you can cover the opening up with decorative wall molding (amazon link).
Measure the gap and attach a molding that effectively covers it up. For a uniform appearance, go for a molding that complements the design of your baseboard.
Install Trim Strips
You can install trim strips (amazon link) if you are averse to applying caulk on your wall. The strips are self-adhesive and easily fit into gaps.
They come in different colors and dimensions, so purchase one that best suits your project.
You can read more about fixing the gap in my article Seal Baseboards to Stop Drafts.
Sources
https://www.helitechonline.com/foundation-repair/problem-signs/wall-floor-gaps/#:
https://www.baycrawlspace.com/the-3-causes-of-uneven-floors-and-how-to-fix-them/
https://www.rocketmortgage.com/learn/buying-a-house-with-uneven-floors#