Home » Gaps in Hardwood Floor, Between Planks, How to Fill Them

Gaps in Hardwood Floor, Between Planks, How to Fill Them

It is common to have gaps in hardwood floor after installation or when the floor gets old. This happen when wood loses its moisture content.

Gaps in wood floor are influenced by factors such as indoor humidity levels, weather changes, radiant heat below and negligibly by installation or milling errors.

Wood is a natural material that responds to changes in humidity and temperatures. Higher levels of humidity during summer or rainy season causes wood to absorb moisture and expand.

If not controlled, floor boards will swell and your wood floor will start cupping and buckling.

The opposite happens during a colder weather and dry winter seasons when indoor humidity is low.

The wood lose moisture and starts to shrink as gaps form between boards.

This behavior of wood will take place even on a quality and properly installed hardwood floors.

Gaps in Hardwood Floor, Between Planks, How to Fill Them

Gaps in hardwood floors resulting from weather changes can be ignored or be minimized by controlling indoor humidity levels by invest in a humidifier.

Condition your home to 30% -50% of humidity and temperatures of 60°- 80° degrees.

Although rare, hardwood floor gaps can be caused by milling and installation errors. During manufacturing, wood planks are made with exacting tongue and groove, height and width as well.

Moisture testing and weight sampling are also carried out. This is to meet the standard requirements set by governing bodies such as NWFA.

Nevertheless, the structural component of the wood can be affected during storage, shipping or acclimation to end up with bend, split end or planks with different width that may affected the flooring outcome.

High temperatures from sun or under-floor heating from furnaces can lead to separation lines forming between the floor boards.

Excessive heat makes wood to loose moisture, dry up and shrink. In the long run, locking joints and seams are also weakened thus squeaking of your wooden floor.

Large gaps in both new and old hardwood floors should not be ignored. Dust and debris settle in those gaps and makes cleaning to be difficult.

Such matter resting in the gaps absorbs moisture and begins to decompose. In the long run, mold will start to grow or wood will decompose along with.

Gaps are also a tripping hazard. You can stumble or fall when you unknowingly hit a raised area of a floor.

In addition, separation lines can steal the aesthetic value of your hardwood floor. A smooth and intact floor is usually beautiful, durable and valuable.

How to Fix Gaps in Hardwood Floors

Fixing a gapping floor on time is the right initiative for caring and maintaining a wooden floor. Methods used for filling them depends on their size, number and the nature of the floor itself.

Too many or wide gaps may require extensive repair by a professional wood worker while few or small ones can be done by yourself.

A floor with too many gaps that can be extensive to repair should be replaced completely to maintain its beauty. This may also be a case where the cost of repairing nears that of replacing.

Filling gaps in hardwood floor can be done using a stained rope, wood putty or with wood strips.

Filling floorboard gaps with stained rope

A natural rope is a commonly used for filling gaps in hardwood floors found in many old homes.

The rope has to be stained so that it looks exactly like the color of the floor. How to do it:

  • Clean the gaps to remove debris and all dirt. If there is old putty, remove using a paint scrapper carefully as you avoid damaging the wood. Vacuum or use a brush to ensure the gaps are clean and clear.
  • Obtain a rope that is slightly larger in diameter than the gap and soak into a wood stain. Remove the rope after it has saturated and carefully place on a cardboard so that it can air dry.
  • String out the rope along the gap line and press it using a putty knife so that it can perfectly fit.

Using wood putty to fill gaps in wood floor

Wood putty or fillers can be used on small stable openings that are not caused by change in humidity.

It is unfortunate that this method is not permanent if you are dealing with floors affected by humidity. 

When the boards expand or contract, the putty or filler also separates. How to use:

  • Clean the floor boards and make the gaps clear
  • Take a wood putty and fill into the gaps using your finger
  • Remove excess putty or filler using a putty knife without scratching the finish
  • Smooth out the party by moving a damp cloth along the gap line
  • Let the party dry then apply a stain to match the color of your wood

Fixing gaps in hardwood floor with wood strips

This method works best for wider gaps.

Shape a strip of wood from spare floor boards or any of the same wood species and proceed as follows:

  • Apply some glue around the wood strip and fit into the gap using a hammer.
  • After the glue has dried, sand the wood strip to the same level of the floor without damaging the finish
  • Apply a wood stain on the strip to match the rest of the floor.

Filling gaps in hardwood floor with sawdust

Fine saw dust mixed with wood glue or polyurethane is a quick fix for gaps in wooden floor.

What to do:

  • Get saw dust preferably from your sanding pad or miter saw and mix with a wood glue or sealant
  • Apply the paste into the gaps and let it dry for 10 minutes
  • Apply some finish or marker so that it can match the rest of the floor.

How to prevent gaps in hardwood floors

To avoid gaps and cracks in hardwood floors caused by expansion and contrition, we recommend the following:

  1. Acclimate the wood to the new environment for 10 days or more before installation
  2. Use a hardwood floor underlayment paper to prevent moisture migration up through the subfloor from wet or damp basements
  3. Invest in digital hygrometer for daily monitoring of relative humidity and maintain them between 30 -50% using a humidifier.
  4. Use engineered hardwood for flooring in highly humid and hot areas
  5. Properly seal and finish hardwood floors to avoid absorption of moisture
  6. Use quality wood with higher janka ratings for flooring

The bottom line

While gaps in hardwood floor may be a normal thing, they should be prevented or be fixed as soon as they are discovered.

Do not let them ruin the beauty and value of your investment.

A well maintained wooden floors will remain attractive for decades to come.

Leave a Comment