How To Tell If A Wood Is Pressure Treated 1

How To Tell If a Wood Is Pressure Treated


To ensure that the wood will last for many years, Dr. Karl Wolman discovered a technique known as pressure treatment. In this process, the wood is placed in a de-pressurized tank to remove the air so that the preservative that will be injected on it can effectively protect the wood from fungus, insects, vermin, and mites.

Pressure-treated wood is considered as the wood for all seasons because it is rot and insect resistant. It can also withstand the changing weather conditions. Like the natural or unpressured wood, pressure treated wood also serves the same purpose.

But, how to tell if a wood is a pressure treated?

Pressure treated wood is suitable outdoors because of its durability components while unpressured wood is suitable indoors because it doesn’t contain any harmful substance.

There are two methods of treating wood, it is the non-pressure and pressure method.

The non-pressure method uses superficial treatments such as spraying, brushing and dipping the wood to be treated in a solution while the pressure treated method undergoes a deep penetration.

In this article, we will know more about pressure treated method in preserving lumber or woods.

What You’ll Need to Follow This Tutorial

Aside from the senses, you need gloves, mask, and moisture meter to determine if a wood is a pressure treated to not, most especially if you need to test high-volume of wood.

Tips for Identifying Pressure Treated Wood

Newly treated wood include tags that have an identification of what chemical has been used. The wood will have green or brown distinguishing marks from the treating process. This discoloration is due to the chemical reaction.

Newly Treated Wood Include Tags 1

Image Source

As the wood ages, it may turn into color gray. Pressure treated wood has an oily scent. Pressure treated wood is more expensive than a regular wood. Pressure treated wood is more compatible with other building materials

Pressure Treated Wood Has An Oily Scent 1

Image Source:

How to Tell a Pressure Treated Wood

Step 1

Pressure treated wood is suitable for outdoor use wherein insects can’t be avoided and so that it won’t be directly contacted to humans. Pressure treated woods should not be burnt because it contains s high level of toxicity. If you needed to dispose of it, it is safer to bury it or take it into a dump.

Pressure Treated Wood Is Suitable For Outdoor Use 1 1

Image Source:

Step 2

Never use pressure treated wood in making chopping boards because it may contaminate the food. The best way to avoid contamination from pressure treated wood is to do your research about the safest treated timber that has the lowest hazard level before purchasing it.

Never Use Pressure Treated Wood In Making Chopping Boards 1

Image Source:

What Chemicals are Used for Wood Pressure Treatment

  • The extremely toxic substance that is used to treat woods is the CCA or the Chromated Copper Arsenic. Nowadays CCA is considered a harmful substance but it is still considered as the most effective substance to treat woods. This substance provides ultraviolet (UV) protection to avoid wood burn especially if the wood is in outdoors.
  • Copper azole is a major wood preservative that is related with some organic substance to protect crops that is why the level of its harmful elements injected on the wood is relatively low.
  • Copper Naphthenate is also a substance used for woods to be used in fences, railroads, greenhouses etc. This substance is the one responsible for making the wood preserve its sturdiness. It is suitable for woods to be used in ground and water contact.
  • Borate preservatives contain a low level of toxicity to humans. It is the substance that prevents molds and fungal growth.
  • For retardant treated contains a chemical that stabilizes the temperature especially in high temperature environments. This chemical also serves as a physical barrier to avoid flame spread.
  • Creosote is used for woods to be used for industrial purposes only such as railroads and utility poles because it contains high coal content.

Helpful Videos


Pressure treatment is a very important process when it comes to wood preservation. It has some advantages like it avoids degradation problems due to fungal rot and it avoids problems related to wood-destroying insects, pressure treatment is also very important for exterior construction because it defies aging.

But on the other hand, the downside is that some chemical components to treat the wood is harmful to living things if exposed to treated woods. There are already new techniques for treating lumber safer. Did you find this post useful? Share and leave a comment below.

You May Also Like