What Causes Dark Spots On Hardwood Floors

What Causes Dark Spots On Hardwood Floors

Hardwood is a fantastic option for any lover of aesthetic value for the home because it gives your living place a very splendid and delicate look. Hardwood floors make homes more elegant than routine flooring. What causes dark spots on hardwood floors always remains in question. 

Hardwood flooring is a popular choice for many homeowners and commercial spaces, due to its aesthetic beauty, durability and timeless appeal. Hardwood floors are made of solid or engineered wood. Hardwood flooring is needed to improve the value and aesthetic beauty of the places. 

Table of Contents

There Are Two Main Types Of Hardwood Floors

Solid Hardwood Floors:

Solid Hardwood Floors

Flooring constructed of solid hardwood is a single piece of wood that is approximately 3/4 inches thick. It can be put in place using a staple-down or nail-down technique. Solid hardwood floors are a durable alternative because they can be sanded and refinished numerous times.

Engineered Hardwood Floors:

engineered hardwood floors

This is a type of flooring that is made up of several layers of veneered wood. Real hardwood is used for the top layer, and high-quality plywood or other materials are used for the lower layers. 

Engineered hardwood is less likely to expand and contract as a result of variations in humidity since it is more dimensionally stable than solid wood. It can be put in several ways, including floating, gluing down, or stapling down.

Scientific Knowledge About Wood

Cellular Structure:

Xylem cells, which are in charge of moving water and nutrients throughout the tree, make up the majority of the cells that make up wood’s cellular structure. The wood’s strength and stiffness come from the secondary cell wall, which contains lignin and is built up of cellulose in the primary cell wall.

Growth Rings: 

Growth rings, which are concentric circles with alternately spaced bright and dark bands, are visible when examining a tree trunk in cross-section. 

These rings are a representation of the annual growth cycle, with the lighter bands (earlywood) created during the spring’s rapid development and the darker bands (latewood) created during the summer’s slower growth.

Natural Resistance: 

Some types of wood are naturally resistant to rot, fungi, and insects. Examples include teak and Ipe, as well as cedar, redwood, and several tropical hardwoods.


When obtained ethically, wood is a renewable resource. Replanting trees to replace those that have been cut down is a component of sustainable forestry practices.

Natural Corrosion:

Given that it includes acetic acid (C2H4O2), wood is naturally corrosive. Wood is more instantly caustic when it is kiln-dried than when it is air-dried because kiln-drying hastens the generation of free acetic acid. 

Corrosion levels are higher in species with low ph. One of the most acidic and metal-corrosive wood species is oak, which has some of the lowest pH values. The main organic components of wood fiber are cellulose, hemicellulose, and lignin, but wood can also contain volatile alcohols, esters, and oils that can make an environment even more prone to corrosion when mixed with metal and corrosive chemicals (like floor finish).

The Hardwood Floors Are Made Of

As you are already aware of this formation, hardwood floors come from trees, and trees have knots. And these knots in wooden floors are not produced intentionally. But rather than they grow naturally in woods. 

These knots are made of the branches that grew from the trunk. Later on, these branches are cut off, and there left a hole and void in the wood. To fill these voids a harder and more durable material is used to fill them, known as a knot filler. 

The complete hardwood flooring involved cutting, and milling knots into planks or boards. To enhance the natural beauty of hardwood floors, knots are intentionally used. 

Wisely Use Of Knots:

The manufacturers use these knots wisely for hardwood floors. Typically highly graded floors have fewer knots. It is important to know the formation of knots in hardwood floors is natural.

It is a worse condition to own some gorgeous hardwood flooring, and its beauty is ruined by some filthy and pesky dark spots. What causes dark spots on hardwood, to meet this situation you need to go through this guide to figure out the causes of these dark spots and how you can get rid of them.

The Best Types Of Wood Which Can Be Used For The Hardwood Flooring

Dark Spots On Hardwood Floors

Before investigating what causes dark spots on hardwood floors we should be aware of the best woods for the hardwood floors.

There are several types of wood which can be used for hardwood flooring. And the choice of wood depends on the aesthetic sense of the users, durability, and budget.


Oak is commonly used for hardwood flooring. It is famous for its resistance, durability, and strength. It is available in two varieties: Red Oak, which is a warm reddish in tone, and white oak, which is slightly light and more neutral in appearance.


Maple is famous for its hardness and durability, it is light and creamy in colour. Due to its resistance to dents and scratches, it is commonly used in high-traffic areas. It can be used in various styles.


The use of cherry wood for hardwood flooring gives a warm, rich, and luxurious appearance. It is reddish-brown which over time with exposure to light becomes deepen and mellows. It is softer than maple and oak so it could be more prone to scratches and dents.


With a prominent grain pattern, it has rich dark brown tones. That gives a more sophisticated and beautiful look to the hardwood floor. Walnut wood is more susceptible to dents and scratches because it is a softwood. With lower foot traffic areas, it could be a stunning choice.


Due to its durability, and strength, hickory is dense and hardwood. It is good for the area which is under heavy experience. Its colour is ranging from light blonde to medium brown. It has colour variations with a varied grain pattern and rustic appeal. 


A well-liked green alternative for flooring is bamboo. It has a sleek, modern appearance and is a quickly renewable resource. However, not all bamboo flooring is created equal, so picking a reliable provider is crucial.


With its rich, reddish-brown colour and opulent appearance, mahogany hardwood flooring is a popular choice. Although it is more expensive, it significantly increases the value of your house.


Ash hardwood flooring has an even grain pattern and a light colour. It is dependable and appropriate for regions with heavy traffic.


These are only a few of the various wood types, that can be used for hardwood flooring. Each type has its distinct qualities, so choose the right one for your hardwood flooring after taking into account all elements like price, durability, beauty, and care needs.

Reasons Behind What Causes Dark Spots On Hardwood Floors

Water Damage: 

water spots are common reasons to make hardwood floors spotty. Water can make the fibers of wood swell, which becomes the cause of dark spots. 

When Moisture sip into the fiber can cause discoloration and dark spots. It happens due to leaks, spills and excessive humidity in the environment. Highly humid areas suffer more for this reason, such as the kitchen and bathroom.

Pet Accidents: 

The enzymes in the substance of urine or vomit of the pets can cause dark spots on the hardwood floors. Such pet accidents may increase the risk of wood fibers breakout.

Chemical Spills:

Some spills of chemicals which are not friendly to the hardwood floor can ruin the durability of the hardwood floor. Bleach or paint thinner chemicals cause dark spots on the hardwood floor surface. 

It could be acetic acid, oil, nail enamel remover, milk or one of the other countless chemicals that are a threat to any hardwood floor. Wipe up all the spills immediately to save your hardwood from damage.

So there is a need to ensure that you are being more conscious not to spill any chemicals onto your hardwood floors. 

Chemical Reactions:

If the use of a certain type of cleaning chemical or product is not used correctly, it can react with the natural oil and finishes of the wood and can create dark spots on the hardwood floor.

Grim and Dirt:

The situation of grim and dirt mainly occur where is a lot of foot traffic, and people walk barefoot. Over time due to the grim and dirt wood fibers start to discolor the surface of the hardwood floor. This could be a cause of dark spots on the hardwood floors.

Moth Damage:

Moths can damage the hardwood floor if the floor is not properly sealed. They will lay their eggs and leave the larvae to eat the well-furnished hardwood floor. This is also a cause of dark spotting on the hardwood floors.


The growth of mildew is promoted by excessive humidity and moisture level. That can also answer what causes dark spots on hardwood floors. These organisms become the reason for rusty odors and dark spots on the hardwood floors. 

Sunlight Exposure:

The area which remains under prolonged sun exposure suffers dark spots. This is commonly observed in areas cleaned up from furniture or rugs. Continuous sun exposure is the cause of dark spots on the hardwood floor.

Wear and Aging:

Due to wear and tear the hardwood floors start to show dark spots. Constantly abrasion of the hardwood floor area can darken and become discolored, which stimulates what causes dark spots on hardwood floors.

Ink Stains:

An ink stain can cause of dark spot on your hardwood floor because it penetrates the delicate fibers of classy wood, and make it spotty. 

Sticker Spots:

During stacked on the wooden boards, on top of one another creates blue or brown spots, as a sticker stain. Which could not be sanded out easily. This is because of thin strips placed between the boards to flow the air through them.

Blotchy Dark Spots:

Blotchy stain or colorant refers to the appearance of a different colour in different areas of a finished floor. The inequitable absorption of stain or colorant is frequently just a physical trait of the wood species itself (such as maple, black cherry, and pine). The colour of stained or coloured floors should be consistent.

Due to inherent variations in the wood, colour tones might change from board to board or even within a single board. Failure to adhere to the manufacturer’s recommendations or the NWFA Sand and Finish Guidelines sometimes results in blotchy stains. 

Improper sanding, improper stain application, incompatible products, failing to give the surface enough time to cure, and many other possible causes are a few examples.

Tannic Acid:

It naturally occurs in trees. Some oak subspecies, walnut and mahogany have particularly high levels. And this acid is within tannin can, the use of the wrong finishing product can cause dark spots or patches on your hardwood floor.

Sap Spots:

If there is any sapwood it means that fungus may be growing on the surface or the interior of the hardwood floor, known as sap spots. It would not become the cause of any danger to the health of your hardwood floor.

But it may cause some changes which can make you unhappy. And it will describe what causes dark spots on hardwood floors. 


For the proper treatment or preventive measures of the spotty hardwood floor. It is essential to investigate the actual point behind what causes dark spots on hardwood floors. 

To address the root cause it is necessary to identify what causes dark spots on hardwood floors. If you cannot solve the problem it is necessary to call the wood expert to handle your situation.

A Few Things Can Be Done To Remove These Dark Spots From The Hardwood Floor

The best solution depends on the actual understanding of what causes dark spots on hardwood floors.

For Water Damage:

The damage from the water spots can be removed by sanding the affected area and refinishing the hardwood floor. Water spots can be removed with a mixture of two parts of water and one part of vinegar. 

Apply this solution with a mixture-soaked cloth and rub it into the dark spot. After this, rinse the area with fresh water and dry it with a clean cloth. It will be helpful to get rid of water spots from your hardwood floor. 

For Pets Accidents: 

With the use of a pet strainer remover, you can clean your hardwood flooring. Due the pet accidents, dark spots can be treated by using a pet stain remover.

First of all, make sure this stain remover will not damage your hardwood floor. So test the remover in an inconspicuous area. 

For the pet accident spots you need one part of hydrogen peroxide and two parts water, apply this solution with a cloth and rub it into the stain. And let this solution be for 15 minutes, then rinse the area with clean water and make it dry with a clean cloth.

For Inkpots:

There is a need for a mixture of one part of alcohol and two parts of water, apply it with a swab or cotton ball on the ink spots. Then rub it into the ink spot, then blot it up with a clean cloth. It will make your hardwood floor spot free.

For Sunlight Exposure:

Avoid prolonged exposure to direct sunlight since it can fade and discolor hardwood flooring. Reduce the damaging effects of sunlight by covering windows with blinds, drapes, or UV-protective coatings.

For Chemical Spills:

If the cause of dark spots is chemical spills, you should use a commercially designed cleaner. Read carefully and always follow the instructions on the cleaner.

For Grime And Dirt: 

Using a hardwood floor cleaner you can remove the dark spots of grime and dirt. waxing and polishing also remove dark spots and make the hardwood floor clean.

For The Damage Of Moth:

If your hardwood floor is spotty due to the moth damage. Professionally refinished make your floor spots free. Before applying any refinishing just make sure what causes dark spots on hardwood floors. 

For Water Damage: 

To save hardwood floors from water stains make your floor always clean at the spot if there is any spill of water or any other liquids.

It will keep your hardwood floor looking better for years. Always wipe up all spills immediately for long-lasting durability.

For Oily And Greasy Spots:

These oily and greasy spots can be removed with the use of mild dish soap or water solutions. Just apply dish soap and rub it with a clean cloth, then rinse it with water. It will help to remove these dark spots from your hardwood floor.

Precautionary Measures To Prevent Black Fungus Growth On Harwood Floors

  • Keep wooden surfaces dry and spotless.
  • Address moisture problems and water leaks right away.
  • In enclosed areas, be sure the ventilation is adequate.
  • When possible, expose wood surfaces to sunlight.
  • Check and preserve wood surfaces frequently, especially in places where moisture is a problem.

If black fungus develops on hardwood floor surfaces, take the necessary cleaning measures to get rid of it, and deal with the underlying moisture issue to stop it from reappearing. 

Consider getting expert help if the mold development is severe or chronic to guarantee that the wood is completely removed and restored. Before any considerations, we should know what causes dark spots on hardwood floors. 

There Are Some Standard Actions Which Can Increase The Durability Of Your Hardwood Floor And Can Keep It Clean

Sweep Or Vacuum Your Floors Regularly:

Regularly sweeping will make your floor grime and dirt free which could become the cause of dark spots o your hardwood floors. 

Regular cleaning will increase the age of your hardwood floors. Use a floor-brush attachment to prevent surface scratches.

Regular Use Of Hardwood Cleaner, Wax, Or Polish:

Regular cleaning with wax, cleaner or polish can make your hardwood floor spot-free because it helps to save your floor from penetration of dirt, grime, and other substances to the surface.

Refinish Your Hardwood Floor Every Few Years:

Yearly professional refinishing will help to restore and protect your hardwood floor fibers from damage. It will help to make your hardwood floor spots free. 

Refinishing is necessary from time to time since hardwood floors can develop wear and surface damage over time. Refinishing can improve their appearance and give them another layer of protection. For advice and instructions on refinishing, seek professional assistance.

There Are Some Steps You Need To Follow For Your Spotless Hardwood Floor

Gather Some Supplies:

You should have these supplies at your home for the safety and beauty of your hardwood floor. Like clean cloth or sponge, dish soap, hydrogen, alcohol, vinegar, microfiber cloth, or bucket.

Test Any Cleaning Solution: 

Always ensure what causes dark spots on hardwood floors, then use that chemical which will not harm your hardwood floor. 

You Can Choose The Suitable Cleaning Methods For Your Hardwood Floor

Always consult the manufacturer company of your hardwood flooring to ensure the use of proper products for different types of dark spots. The use of the wrong products not only can make the spots stubborn but also ruin your hardwood floor.

So, before the selection of cleaning methods, discover what causes dark spots on hardwood floors. 

Here Are Some Suggestions To Increase The Durability And Lifespan Of Hardwood Floors:

Pick The Correct Hardwood:

Choose species of hardwood like oak, maple, or hickory that are renowned for their durability. These hardwoods can withstand more damage and wear.

Install Safety Precautions:

Set up doormats at the entrances to catch dirt and stop it from scratching the floor. To avoid dings when moving furniture, felt or rubber padding ought to be nailed to the bottom.

Cleaning the hardwood floor regularly will prevent scratches by removing dust, dirt, and other contaminants. To prevent scratching the surface, use a soft broom or a hoover with a floor-brush attachment.

Prevent Too Much Moisture:

Water and too much moisture can destroy hardwood floors. Clean up spills right away, mop with a damp (not wet) mop, and use as little water as possible while scouring.

Control Interior Humidity Levels:

To prevent excessive expansion or contraction of the hardwood, which can result in warping or gaps. The recommended range for indoor humidity is between 35% and 55%. When necessary, use a humidifier or dehumidifier.

Avoid Wearing High Heels:

Avoid wearing high heels and letting your pet have untrimmed nails on your hardwood floors since they might scratch or dent the surface. Trim your pet’s nails frequently to reduce the chance of injury.

Use Area Rugs And Runners:

To add another layer of protection for the hardwood, place area rugs or runners in high-traffic areas like hallways or entranceways.

Exercise Caution:

When moving furniture and large, heavy items by lifting them rather than dragging them across the floor. If required, use furniture sliders.

Several Benefits of Harwood Flooring

There Are Various Benefits To Hardwood Flooring, Including:

Elegance and Timeless Appeal:

Hardwood flooring complements a variety of interior design styles by adding warmth, charm, and a classic appearance to any room.


With the right upkeep and care, high-quality hardwood floors can last for decades. To eliminate scratches and restore the appearance of solid hardwood floors, they can be sanded and refinished.

Easy Upkeep:

To keep hardwood floors looking beautiful, regular sweeping and occasional cleaning is typically adequate.

Better Indoor Air Quality:

Hardwood flooring helps to improve indoor air quality since it does not hold dust, allergies, or pet dander as readily as carpets do.

Better Indoor Air Quality: 

Hardwood flooring helps to improve indoor air quality since it does not hold dust, allergies, or pet dander as readily as carpets do.

Increased Property Worth: 

Hardwood flooring is a desirable characteristic that can raise a property’s worth in the eyes of potential purchasers.


Although hardwood flooring has many benefits, it might not be the best option in every setting. It may need careful upkeep in regions that are prone to spills or high humidity because it might be susceptible to moisture. Additionally, hardwood flooring can cost more initially than other flooring options, but for many homeowners, its long-term durability and attractive appearance make it a good investment.

Final Thoughts

Finding the source of dark stains on hardwood floors is essential for solving the problem. Dark spots brought on by water damage or wear can be avoided by promptly cleaning up spills, utilizing area rugs or mats in high-traffic areas, and performing regular maintenance. 

Professional cleaning and refinishing may be required for particularly difficult stains. Regular maintenance, shielding the wood from moisture, using the right cleaning supplies, and limiting exposure to direct sunlight are all necessary to prevent dark spots on hardwood floors. 

Your hardwood floors can look their best for years to come with routine inspections and quick responses to spills or stains. Since Hardwood floors have been started it has become the part of aesthetic sense of people. Those who want to give a standard to their living prefer to use hardwood flooring because it provides a splendid glance. 

So where it is a fantastic idea to enhance the beauty of the floor, we should be careful about its durability. For a sparkling look, you should always be conscious of the dark spot which can decrease its beauty.

Always be sure that you are buying your hardwood floor from a trusted business industry. Who only use the best quality to make your living beautiful, and engineer your hardwood flooring to keep prevented deep dark spots. 

It is very important to choose a finishing hardwood that complements the style of flooring. Always test and ensure the use of chemicals you will use for the hardwood floor,

By visiting the rest of the site, you can find more useful articles that can help you learn more about a topic or find answers to your questions.

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