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How to Fireproof Wood [A Complete Guide With 2 Methods]

Architects are emphasizing the need for fire safety plans in recent years. A major part of this plan involves the use of fire-resistant wood in high-traffic areas. Having fire-resistant wood significantly reduces the chance of widespread fires.

How to fireproof wood?

A mixture of Zinc chloride, Ferric chloride, Boric acid, and Ammonium phosphate can make wood fire-resistant. Mix the chemicals with water to make a saturated solution and spray it on the wood. Spray several times to form layers of fire-resistant coating on the wood surface.

There’s more information regarding this topic that needs to be elaborated on. Stay with us till the end to acquire a profound understanding.

Why is It Necessary to Have Fire Resistant Wood

Woods with high flame resistance are becoming the standard building material in modern houses.

The growth of the capitalist economy saw a surge in traffic in the cities. This also gave rise to an unwanted threat in the form of fire hazards. To reduce the possibility of widespread fire, architects are adopting smarter approaches with wood.

Wood is one of the most versatile building materials out there. But being prone to heat, woods are one of the first things to catch fire. There is a high chance that the fireplace gas turns on and the firewood catches fire.

Many methods are implemented to make woods fire-resistant in order to halt the widespread fire. Fire-resistant woods can temporarily resist heat, giving you enough time to put out the fire.

How to Make Wood Fireproof

Most of the widely used fireproofing methods are expensive and require an abundance of raw materials. Those methods are adopted for industrial purposes.

But don’t let that kill your motivation. I’m going to show you 2 cheap, yet effective ways to make your wood flame-resistant. It won’t cost you much and the chemical components are easy to acquire.

Keep in mind that these methods won’t make woods 100% fireproof. They will only make wood heat resistant to some extent only.

With that said, let’s get straight to the best part!

Method 1: Homemade Flame-Resistant Wood Paint

This method requires very little effort. The chemical components required in it can be found in any store selling gardening supplies. Here’s how you can make it-

Step 1: Create The Solution

Mix ¼ cup of ferric chloride and ½ cup of zinc chloride with 2 quarts of water. Add 3 tablespoons of ammonium phosphate and boric acid to the mix. Stir them to create a saturated solution.

Step 2: Application

Once the solution is created, you can either choose to paint it or spray it. I personally prefer painting the solution on the desired wood. This lets me form a balanced coat on the surface of the wood. It might take longer, but it’s better than spraying.

Let the solution sit on the wood for 30 minutes before attempting another batch of coating. Do this 2 to 3 times and the wood should be ready to resist ignition. 

If you’re painting over furniture, make sure to paint it’s interior too. For example, paint inside the kitchen cabinet when you’re applying the solution.

Method 2: Homemade Heat Resistant Spray

You’ll need only Borax powder and water for this method. Check out these brands offering top-quality Borax powder-


These products give you the best value for your bucks.

The Borax powder contains sodium borate that is resistant to heat. We’ll require that for this method.

Here’s how you can make an effective heat resistant spray-

Step 1: Prepare the Solution

Set the saucepan on the stove and pour a cup of water to boil. Once the water boils, add 3 tablespoons of Borax and stir the solution.

Step 2: Cool Down The Mixture

Wait until the solution cools down to room temperature. Some Borax will remain at the bottom of the saucepan. The clean liquid you are left with is the heat-resistant solution.

Step 3: Apply The Solution

Put the solution mixture in a spray bottle and spray the solution on the wood. Let the solution sit and dry for 30 minutes and spray again. Apply a few layers of coat until the wood is soaked thoroughly.

Prepare a large batch of Borax solution as this method requires a good amount of it. Try to apply the solution to every wooden furniture in every room of the house.

Different Categories of Heat Resistant Woods

Woods selected for flame resistance are taken through delicate processing to make them fire-retardant. Woods such as lumber, plywood, shakes, etc are used for fire-resistant woods.

These woods are categorized based on their ability to withstand heat and counter ignition. I’ve tried my best to explain them in simple terms below-

Class A

The woods that fall in this category have the most resistance against fire. It can stand its ground for a minimum of 30 minutes without catching fire. Class A woods have a flame spread index of near 25.

Class B

The flame spread index of this category of wood hovers anywhere around 26-75. Simply coating any untreated wood with fire retardant coating can make it fall under this category.

Class C

This is the lowest category for heat-resistant wood. Class C can have a flame spread index of 76 all the way up to 200.

Untreated woods fall into this category.


Question: What is flame spread index?

Answer: Flame Spread Index, also known as FPI is the measure of a wood’s resistance to flame. This measurement counts how effectively a wood can withstand fire from spreading on its surface.

Question: Why is Canadian Pinkwood colored pink?

Answer: Canadian Pinkwood is coated with a special kind of fire retardant that’s pink in color. This pink retardant can absorb massive amounts of heat without getting ignited for a long period.

Question: Is bamboo resistant to fire?

Answer: No, bamboo is not well known for its resistance to fire. Bamboo is one of the easiest types of wood to catch fire. Exposure to flame can easily ignite a bamboo and it’ll burn down without much effort.


You just learned how to fireproof wood. Keep in mind that these won’t make your wood completely fireproof. They will only increase the wood’s resistance against ignition. 

Have a great day!