How To Fill Gap Between Vanity And Wall: 6 Easy Solutions

One of the biggest challenges you may have when remodeling a bathroom is finding the perfect vanity – especially if you want it to be flush with the wall. Not only will you have to find the right vanity size, but the wall must also be perfectly straight, or you’ll end up with gaps. What to do now?

If your vanity is almost flush with the wall, you can fill the gap with silicone caulk. Adding a backsplash or backer rod could fix a gap between the vanity and the back wall. Alternatively, you could tile a side wall or use a vanity filler strip.

How To Fill Gap Between Vanity and Wall

Gaps between vanity and wall fall in one of the two categories: a gap between the vanity and the back wall or a gap between the vanity and the side wall. The latter is more frequent than the former, but the former is more annoying because the back of the vanity should actually be flush with the wall. With this in mind, let’s see how to deal with those pesky gaps.

Filling Gap Between Vanity and Back Wall

When it comes to installing a vanity, there should be no gaps between it and the back wall. However, gaps could occur if your wall isn’t perfectly level. Not only are these gaps annoying to look at, but splashed water can gather between the vanity and the wall, damaging the wood and creating the perfect environment for mold and bacteria to thrive. 

Gaps between the vanity and the back wall aren’t generally large and are easy to fix. Here are three quick solutions.

Caulk Smaller Gaps 

If you only have to fill one or two small gaps, you can do so with silicone caulk. Silicone caulk comes in transparent and white options, making it a good choice for all bathroom colors.

To fill the gaps, you need a tube of caulk and a caulking gun. Hold the gun at a 45-degree angle and apply a small quantity of product. 

Put on a pair of latex gloves and spread the caulk along the line between the wall and the vanity. Repeat if needed and wait a few minutes for the caulk to dry before using the sink.

Use a Thick Backsplash

Another easy way to fill a smaller gap is with a thicker backsplash. You can choose from a wide range of models made from an array of materials, from wood to glass. Plastic and glass backsplashes are the best choices if you want superior water resistance.

No matter what type of backsplash you install, remember to seal the edge between it and the vanity with silicone caulk to prevent water from leaking in-between.

Use a Backer Rod

Sometimes, there is a gap between the vanity and the back wall because the sink requires a greater space for proper installation. These mid-size gaps are easy to mask with a backer rod.

Similar to a wall trim, the backer rod goes on top of your vanity and is flush with the wall, giving your bathroom a streamlined appearance. 

Attach the rod to the vanity with color-matching caulk (or a clear-drying type if you can find silicone caulking in the right shade) and seal the edge between the rod and the wall with another thin layer of waterproof caulk. 

Filling Gap Between Vanity and Side Wall

While most gaps between a vanity and a back wall happen because the wall is not level, gaps between the vanity and the sidewall can happen for a number of reasons. For instance, the wall may not be level, and you can’t install the vanity flush with the side wall. You may have trouble finding a large-enough vanity. Or the vanity may simply be located toward the center of your bathroom, at a distance from the side wall. Depending on your circumstances, there are various ways to solve the problem.

Tile the Side Wall

If you have a small bathroom with a vanity placed in the corner of the room, you may notice that it isn’t flush with the side wall. This happens because the wall is not level. 

You can fix this kind of mishap by tiling the wall – it works in the same way as a backsplash, but the solution is more adequate for the side wall. The trick is to only tile the upper side of the wall from right above the vanity edge. In this way, the edge of the tile can fill the tiny gap between the wall and the vanity.

Add a Vanity Filler Strip 

Vanity filler strips are excellent choices for gaps from about half an inch to several inches. These strips are made of plastic, wood, MDF, or vinyl, and all you have to do is to fasten them with nails to the sides of the cabinet.

Filler strips act as a bridge between the vanity and the wall and represent an ideal solution for those awkward spaces left by a vanity that isn’t quite the right size.

Add Shelving or a Side Cabinet

If you have several inches of space that you’d like to fill, add shelving or a side cabinet. You can opt for one of the two based on the actual space you have.

As a rule of thumb, custom shelving is cheaper than a custom side cabinet. However, if the distance allows you to squeeze a cabinet in there, it would give your bathroom a more streamlined look. Don’t worry if you’ll end up with a smaller gap – you can fill it with a filler strip, tile, or caulk.

How Much Space Should Be Between Vanity Sink and Wall?

According to the plumbing code, you must have a floor clearance of at least 15 inches from the center of the vanity sink to any of the adjacent walls. These measurements represent the minimum required, although most experts recommend at least 20-30 inches of clearance. However, this doesn’t mean that you can’t install the vanity flush with the wall if you want to.

Is it OK to have a 2-inch gap between vanity and wall?

It is not OK to have a 2-inch gap between the vanity and wall. When installing a vanity, you must either install it flush with the wall (so that no objects can fall into the gap) or allow for a distance of at least four inches between the wall and the edge of the vanity if you’re opting for a freestanding installation. 

How to Measure Gap Between Bathroom Vanity and Wall

Measuring the gap between the bathroom vanity and wall isn’t complicated. All you need is a tape measure and a piece of paper.

1. Measure the gap from the center of the vanity to the wall

Measure the length of your vanity and mark its middle, then measure the vanity’s depth and mark the middle. The intersection point is the middle of your vanity. This point must be placed at a distance of at least 15 inches from any wall.

Measure the distance from the middle of the vanity to the back wall and mark any necessary adjustments – this step is important only if you want to install a bowl sink that sits on top of the vanity, as it allows you to place the sink in such a way to respect the International Plumbing Code. Most vanities with a recessed sink already have the sink positioned according to the code. 

2. Measure the gap between the vanity and wall

Considering the measurements above, position your vanity in such a way that the center of the sink is at least 15 inches away from all walls.

Measure the gap between the wall and the vanity with your tape measure. Write down the distance on a piece of paper. For a gap of ¼ of an inch or smaller, you can use caulk to close it. Alternatively, check out the methods above to fill a larger gap.

Related Questions

There are various ways to fill the gap between vanity and wall, but you may still have questions. Find out the answers below.

How big of a gap can you caulk?

You can caulk gaps of up to ¼ of an inch in size. If you wish to caulk a larger gap – but no larger than half an inch – add a bead of caulk deeper into the gap and wait for it to cure before caulking the top of the vanity from its edge to the wall. Stretch the caulk with your finger (covered in a latex glove) for a flawless finish.

Do you have to attach a freestanding vanity to the wall?

You don’t have to attach a freestanding vanity to the wall, but if you want to leave a gap, the gap should be at least four inches on the sides.

What is the code for toilet clearance?

The bathroom building code says that you need at least 21 inches in front of the toilet and at least 15 inches of clearance side-to-side. However, you might want to opt for at least 30 inches in front of the toilet and about 20 inches side-to-side for comfortable use of your bathroom.


Depending on how large the gap between the vanity and the wall is, you can fill it with caulk, a backsplash or tiles, a backer rod, or filler straps. If you have enough space, you could even add a side cabinet, shelving, or store your laundry basket in the gap. We hope this guide can help you pick the best solution for you.

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