How To Fill The Gap Between Wall and Floor: 8 Easy Ways (Do This!)

Discovering a gap between a wall and the floor is often disheartening, but this gap has a functional role. It’s called an expansion gap and exists to prevent the flooring from hitting the wall and buckling or cracking as it expands due to a temperature change. 

As functional as it may be, the expansion gap is unsightly. While getting rid of it is not recommended, filling the gap between wall and floor is easy. Choose the most appropriate method below to conceal it.

How To Fill The Gap Between Wall And Floor (The Right Way)

The correct way to conceal the gap between your floor and walls is with baseboards. Here’s how to do it.

What You’ll Need 

  • Baseboards
  • Miter saw 
  • Tape measure 
  • Bullethead nails
  • Nailing gun
  • Electric drill
  • Wood adhesive
  • Wood putty 
  • Sandpaper 
  • Quarter rounds (optional)
  • Wood paint (optional)
  • Paintbrush (optional)

1. Measure And Determine Miter Angles 

Installing baseboards is an easy DIY project for beginners.

Baseboards come in thinner and thicker designs. Choose one that covers the gap completely – most expansion gaps are between ¼ and ½ of an inch wide. 

Before heading to the home improvement store, measure the surface and determine the miter angles based on the external and internal corners you have to cut. 

Measure the entire perimeter along the walls and add a few inches to account for the cuts. 

2. Prepare The Area 

The gap between the wall and the floor, especially in old houses, can get really dirty. 

Use a vacuum cleaner to get rid of dust, debris, pet hair, and other gunk gathered in the recess. If possible, wipe with an all-purpose cleaner and let it dry thoroughly before proceeding. 

Warning: You might be concerned about heat loss or crawlers getting into your home through this gap. However, filling the expansion gap is not recommended. Rigid materials can block the expansion of your floors, causing permanent damage.

3. Cut The Baseboards 

All baseboards have straight edges on the sides. To create perfect corner joints, you have to cut them at a 45-degree angle. 

Place the baseboards against the wall and mark the corners where needed. 

Use the miter saw to cut the internal and external corners. The video below details how to use a miter saw to cut baseboards: 

4. Install The Baseboards 

Skirting boards are generally attached to wall studs with bullethead nails.

Start from one corner of the room, placing the first baseboard flush against the wall. Pre-drill the nail holes through the board to prevent splitting the wood. Then, drive the nails through the baseboard and drywall into the wall studs with a nailing gun. 

Repeat for all other boards. When joining corners, apply a thin layer of wood adhesive on the miter joints for a perfect fit.

5. Conceal The Nail Gaps 

Fill all nail recesses with wood putty, preferably in a color similar to the color of the baseboards. Alternatively, if you plan to paint the skirting, use white putty.

Let the compound dry and cure as instructed on its label, then sand it with fine-grit sandpaper to smooth out the area.

6. Finish The Skirting 

You can now paint the baseboards in the color of your choice. Water-based wood paint is the best option if you have kids or pets. Alternatively, you can use wood stain or solvent-based paint.

Before painting, you can also install quarter rounds or shoe molding around the baseboard if you want to enhance its aesthetic appeal.

Alternative Ways To Fill A Gap Between Wall And Floor 

The method above describes how to conceal a regular expansion gap between the wall and floor. However, incorrect flooring installation or the natural settling of the house can expand this gap. In some cases, you might even find that you have to fill a 2-inch gap between the floor and walls

If this is the case, choose one of the methods below to conceal it.

Caulk The Gap 

Installing baseboards can help you conceal the expansion gap. However, floors are rarely perfectly straight. 

If you’ve installed skirting boards just to find that there are still gaps between the boards and the floor, use acrylic caulking to smooth them out. 

The easiest way to apply the caulk is with a caulking gun. Hold the gun at a 45-degree angle and lay a strip from one end of the board to the other. 

Smooth it out with a gloved finger, pushing the compound into the gap. Remove excess caulk with a paper towel and let it dry. 

Repeat on the upper edge of the baseboards if you also have to conceal the gap between the wood skirting and the wall.

Use Quarter Rounds 

Quarter rounds are an alternative to caulking for filling large gaps between skirting boards and walls.

Install them with bullhead nails around the skirting boards. Fill the recesses with putty, smooth the surface with sandpaper, and paint them in the same color as your baseboards.

Fill With Cement And Sand

If the gap is two inches wide or wider, you can use a cement and sand mixture to reduce its size before installing skirting. 

Mix sand and cement at a 3:1 ratio (sand:cement), then add some synthetic butadiene (SBR) to the mixture. This synthetic rubber improves the mixture’s elasticity, allowing the floor to expand without cracking or buckling. 

Use a trowel to fill the gap. Make sure to leave about ¼ of an inch between the wall and the filler – the width of a regular expansion gap. 

Let the cement and sand mixture dry, then install the molding. 

Conceal With Drywall 

If you don’t mind losing some inches of floor space, you can conceal the gap with a fake wall. Installing drywall on an existing wall comes with additional advantages, including better insulation and a smoother surface for painting if your existing wall is made of brick or other masonry materials. 

Fasten the drywall panels to the wall with screws, then fill the recesses with acrylic caulk. Sand the excess to smooth the surface and paint in your desired shade. 

Add Wood Filler 

Another way to conceal a large gap between floor and wall, if you have hardwood floors, is with wood filler.

Wood fillers come in a variety of colors. Choose one that matches your floor and use a trowel or putty knife to fill the gap. 

Smooth out the surface – the purpose is to fill the gap flush with your floor and wall. Let the wood filler dry before sanding it to achieve a uniform finish. 

If you want to fill a gap between tile and wall, use silicone caulk instead of wood filler. However, never fill the gap with grout. 

Grout is not flexible and could cause your tiles to crack in case of temperature changes. If you don’t want to use silicone caulk, use caulking strips instead.

You can also use silicone caulk to fill a gap between vanity and wall or to finish tile edges on a wall. 

Fill With Spray Foam Insulation 

Filling a large gap with spray foam insulation could be a solution in an old house, especially if you’re losing heat through the gap or if bugs can get in through the subfloor. 

Simply spray the product into the gap. Let it set and cure as indicated on the label, then remove any excess with a cutter. 

Leave at least ¼ of an inch between the foam and the wall, then cover the entire gap with skirting boards. 

Add An Extra Floorboard

If the gap is particularly large, you can install an extra floorboard. Measure the gap and cut the floorboard to dimension. Nail it down to the subfloor, then use one of the methods above to conceal the area and cover any gaps. 

What Extra Steps Should I Take If I Have An Old House?

You can fill an old house gap between floor and wall in the same way you’d fill it in a new house. However, there are a few extra steps to take before concealing it.

Check Your Walls For Moisture

Give your walls a thorough inspection. Do you see any moisture damage such as visible mold, paint bubbling, or sweating? 

Has moisture seeped through the gap onto the floor? Are there moisture stains on the wall, floor, or carpeting? 

If you find any moisture damage, the wall or flooring itself may need repair or replacement before you fill the gap between the wall and the floor. 

Checking for mold is crucial as it can pose dangerous health risks.

Check For & Repair Cracks

If you have an old house with a gap between the floor and the wall, it’s a good idea to also check if there are any cracks in the foundation concrete, subfloor or walls and repair them. 

For cracks in the foundation, fix them with a concrete patching compound. Some shrinkage cracks in the concrete are normal. 

Mend cracks in the plaster or sheetrock walls with sheetrock tape, drywall mud, joint compound, spackle, and paint. 

While minor cracks are common when houses settle, it’s a smart idea to consider the root cause of major cracks because they may signal a more significant structural issue.

Related Questions

Are gaps between the wall and floor an entry point for bugs and rodents? 

Yes! Check for tiny pinholes or dust piles on and near your walls that may have been caused by termites. 

Also, look for evidence of other bugs or rodents, such as droppings or smears. If you find any evidence, call an exterminator before closing the gaps to be sure you fully address the problem. 

Sealing up the gaps is critical, but it won’t completely solve an infestation problem, especially termites.

However, keep in mind that expansion holes are not the only entry points. Bugs may also get into your house through the drain or vents.

How much space should be between the floor and wall? 

At first glance, there should be no space between your floors and walls. When done correctly, finished carpentry and painting jobs conceal the expansion gaps perfectly. 

Behind the skirting mold, there should be an expansion gap between ¼ and ½ of an inch.


Having an expansion gap between the wall and floor is crucial, but you don’t have to like it. Luckily, there are ways to conceal it regardless of the size. 

Don’t forget, if you live in an old house, look for signs of moisture infiltrating through the gap and other damage before filling or concealing it. If you’re in doubt, don’t hesitate to call a contractor.

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