How To Tell If Wood Is Pressure Treated? (Answered!)
You’ve decided to use pressure-treated wood for your next project.
However, on your way to the hardware store, you still need to figure out whether the wood has been pressure treated.
So, how to tell if the wood is pressure treated?
VIDEO: What Is Pressure Treated Timber?
What Exactly Does Treated Wood Mean?
Treated lumber is lumber that has been pressure treated. First, wood is placed in a pressure chamber containing liquid preservatives. Then, high pressure is applied for the preservative to penetrate the lumber.
Alkaline copper quat, or ACQ, is the most commonly used preservative. This is because copper is toxic to insects and fungi.
As a result, this lumber is more resistant to insect and rot damage, water, and fire, but not moisture, UV rays, or corrosion.
How do you tell if the wood has been pressure treated?
Although all lumber appears to be the same, you should not be intimidated. You can identify pressure-treated wood once you know the signs.
Here’s a handy guide to distinguishing between treated and untreated wood.
Search for an End Tag.
Look for a stamp indicating that the wood has been pressure treated. The end tag should include the preservative used; it is rating, and the preservation company.
Avoid using any wood that has been treated with Chromated Copper Arsenate (CCA). This preservative contains arsenic in some form. This is why, since 2003, they have been prohibited from being used in decks, playgrounds, and similar structures in an outdoor-residential setting.
Locate the Stamp
Borate-treated wood markings are easy to find. A stamp should indicate the type of wood and where it should be used.
For example, if it says “FDN” (foundation), it’s one of the safest types of pressure-treated wood. Builders will sometimes use these as the foundation beneath home flooring.
Borate-treated lumber is just as safe. This is ideal for use in the home because it is safe for people. Bor, Hi Bor, and Tim Bor are the stamps on these.
This is ideal for indoor use because it is termite resistant. However, outside, it may rot, and the soil may not absorb its preservative.
Avoid lumber with the stamp L P22. These have been arsenical treated. On the other hand, wood with an L P2 stamp is less toxic but dangerous for home furnishings.
Obtain a Fact Sheet
The chemicals used in wood pressure treatment are listed on a fact sheet. If it contains Copper and Tebuconazole, it has been pressure treated.
Examine the Color
How does treat wood appear? Pressure-treated wood can be green or brown in appearance and color. Some are tan or olive in color. The appearance may differ depending on the treatment procedure. This is because each preservative has a distinct color.
Perform the Smell Test
If you can’t find a blue, brown, or green tint, pick up the piece of wood and take a deep sniff. Except for CCA-treated wood, which has no distinct odor, treated wood smells like oil or toxic chemicals.
Dimensions of Lumber
Most lumber used in residential construction measures 8 (244 centimeters) to 16 ft (488 cm).
Some 2x4s and 2x6s are precut 92 5/8″ long, a standard length for wall studs.
Chemically injected wood is typically broader and thicker than regular wood. This is due to the chemicals in the wood.
Make use of a Swipe Test Kit or a Wood Testing Kit.
Many commercial laboratories sell a swipe test kit that can detect treated wood.
Determine the Retention Level
The retention level indicates how many preservatives remained after the pressure treatment. The higher the retention level, the longer the wood will last.
Color of Pressure Treated Wood
As you know, the color always corresponds to the chemicals used for wood pressure treatment.
Green Chromated Copper Arsenate
Copper, chromium, and arsenic, or CCA, were infused into greenish wood.
The most effective substance was CCA. It is effective against fungi, termites, and other pests. But on the other hand, CCA wood is toxic to humans and the environment.
Brown Copper Azole (CA)
CA-treated wood has little to no odor. Type A contains copper, boric acid, and tebuconazole, while Type B contains more copper and tebuconazole but no boric acid.
CA offers effective resistance to mold, fungi, termites, and other insects.
Tan or Olive ACQ
ACQ, alkaline copper quat, is a copper and quaternary ammonium compound. ACQ protects against decay fungi and insects. Hardwood is ideal for structural support, such as fence posts; examples include alder, balsa, and walnut.
Softwood lumber is naturally wetter due to the presence of more sap. Fungus and other insects are drawn to the sap because it provides food. Softwood has natural sap pathways that can be used in wood treatment. Coniferous trees, such as yellow pine, white pine, spruce, and Douglas fir, are examples of softwood trees.
How to Determine Whether Old Wood Has Been Pressure Treated
Look for a greenish hue. The color of the wood changes after pressure treatment. Unless the lumber has faded and turned gray, it usually has a greenish tint.
Contact the manufacturer or builder; the wood color fades and turns gray as it ages.
Find out how old the wood or project is. If the deck is over two years old, it has most likely been infused with arsenic unless it is made of cedar. You should be aware, however, that CCA has been prohibited for most residential use since 2003.
How to Determine Whether Plywood Has Been Pressure Treated
Color variation. As a result of the treatment process, treated plywood can have a green or brown color.
A chemical or oily odor. In contrast to the pleasant natural smell of untreated wood, treated wood has a chemical or oily odor.
It’s clearly labeled. Here are some examples of possible labels:
- UC1 is intended for interior, dry use.
- UC2- interior, capable
- UC3A- above ground, exterior, coated (rapid water runoff)
- UC3B- uncoated exterior, above ground (poor water runoff)
- UC4A- general use ground contact
- UC4B- heavy-duty ground contact
- UC4C- ground contact, ultra heavy-duty application
- UC5A- marine application, northern waters
- UC5B- marine application, Central waters
- UC5C- marine application, southern waters
- UCFA stands for interior, above-ground fire protection.
- UCFB stands for exterior, above-ground fire protection.
If you still need clarification, use a swipe or wood testing kit.
How to Determine Whether Wood Has Been Treated for Burning
Never burn pressure-treated wood because it will release chemicals. Furthermore, its ash is highly toxic. In short, no pressure-treated wood is suitable for burning.
The Benefits of Pressure Treated Wood Over Ordinary Lumber
- Moisture resistance: The treatment makes the surface less permeable to moisture, making fungi and mold less likely to grow.
- Resistance to fungi and insects: Most pressure-treated woods contain copper-based compounds such as ACQ and CA. Fungi and other microorganisms are toxic to copper.
- Fire resistance can be achieved by injecting fire-retardant chemicals into the wood.
- Sizes: You can select from various sizes based on your requirements.
- Durability: Despite exposure to the elements, moisture, and insects, they will last longer than untreated wood.
Recommendations for Safety
- Wear protective equipment such as goggles, a dust mask, and gloves. Collect as much sawdust as you can. After working with treated wood, wash your clothes separately.
- Hands should be thoroughly washed with mild soap and water.
- Bleaching – Do not use bleach, sodium hypochlorite, sodium hydroxide, sodium percarbonate, oxalic acid, or citric acid on preservative-infused wood. These could cause the wood to emit chemicals.
- Cut wood outside – Wood preservatives irritate the nose, eyes, and skin. You’ll need breathing room to avoid coming into contact with the chemicals and inhaling them.
- Burning – Never burn treated wood because it may release the chemicals contained within.
- Allow it to dry – This prevents warping, cracking, splitting, and gaps. When wood is wet, it expands due to moisture. However, when allowed to dry, it shrinks. This movement causes warping, which in turn causes splitting and cracking in the wood.
Use of Pressure Treated Wood Indoors: Dos and Don’ts
You can use pressure-treated lumber for indoor projects if you follow the safety precautions. Here are some pointers:
- Examine the type of wood and the chemicals used. The most vital chemicals are present in the lumber made to touch the ground, making it unsafe for indoor use.
- Recognize borate-treated lumber. Borate can be used safely indoors. It keeps bugs, fungi, and other wood-decaying organisms at bay.
- Wear safety equipment. Use gloves, goggles, and a dust mask when working with treated wood.
- Remember to clean up after yourself. Always collect sawdust to avoid inhaling chemicals from the wood.
- Never use pressure-treated wood on surfaces that will come into direct contact with food, animals, people, and the ground or water. Dining or picnic tables, chopping boards, and bed frames are examples.
- Commercial wood materials should not be recycled. Utility poles and railroad ties containing harsh chemicals are examples.
- Exposed treated wood should be stained. This will form a protective barrier, particularly against moisture.
Disposal: Adhere to Safety Recommendations
It is best to get rid of old treated wood. Here are some pointers on how to properly dispose of pressure-treated wood.
Handling with Caution
If you can’t dispose of the lumber immediately, cut it into smaller pieces and place it in specially labeled bins.
Proper Disposal
Only burn pressure-treated wood if you want to get rid of it!
Every state considers this to be illegal. So instead of burning the treated wood, contact your local landfill and ask if they can accept it. They will inform you of approved disposal methods and regulations.
What Causes Pressure Treated Lumber to Warp?
Treated wood warps as a result of not being dried after treatment. There is no de-pressurized tank available for this.
When wet, the moisture causes the wood to expand. However, when allowed to dry, it shrinks. This movement causes warping in the wood, which leads to splitting and cracking.
Is Arsenic present in pressure-treated lumber?
Yes. Some pressure-treated wood contains arsenic. This product contains arsenic. Furthermore, CCA leaches from wood to soil, endangering plants, animals, and humans.
Given these considerations, CCA-treated wood has been prohibited for residential use and is no longer available in hardware stores since 2003. However, it is still permitted for specific industrial and commercial purposes.
Is Treated Wood Corrosive to Aluminum?
Yes. Alkaline Copper Quaternary (ACQ) and Copper Azole (CA), two wood preservatives, contain copper, which discolors and causes corrosion when in direct contact with aluminum.
Who makes the rules for treated lumber?
The American Wood Preservation Association (AWPA) is in charge of disseminating voluntary wood preservation standards. The International Residential Code (IRC) and the International Building Code (IBC) both refer to AWPA standards (IBC).
You can find “AWPA” and the applicable standard, usually “U1,” on the lumber’s end tag. As a result, by looking at the tag, you can tell if that 24 is treated.
Conclusion
Check the tags and stamp markings on the chemicals you use. The green or brown color will also aid in identifying treated wood—even the smell of the lumber. If you still need clarification, ask your favorite hardware store employee.
It’s best to be specific, so you know which one to buy and can reap the benefits of using pressure-treated wood.
FAQ on How To Tell If Wood Is Pressure Treated
What color is wood that has been treated with pressure?
The treatment technique is responsible for the tendency of newly installed pressure-treated wood to have a bluish-green or dark brown hue to it when it is first placed; the color of the wood depends on the variety that was chosen. Even after just a few weeks of being exposed to the sun, the color will convert into a color that is closer to its original state.
What kinds of markings can you find on pressure-treated wood?
You may find the initials “PT” or “GC” either on the stamp or on the shelf of the lumber in question if it has been pressure treated for use in an outdoor environment. The acronym PT stands for “Pressure Treated.” There are two primary camps in PT: the Ground Contact camp and the Above Ground camp. There are certain vendors who will only sell pressure-treated Ground Contact lumber to their customers.
What does ancient pressure treated wood look like?
Newer pressure-treated wood has a stamp identifying it as such, and in certain circumstances, an alphanumeric code providing information on the amount of toxicity. Older pressure-treated wood has a tinge of olive green, while newer pressure-treated wood has a stamp identifying it as such.
How do you tell if the wood that has been pressure treated has dried out?
Use the “sprinkle test” to assess whether or not the wood that has been pressure-treated is dry enough to be stained. Sprinkle water onto the board; if the water is absorbed by the wood within ten minutes, you should begin the staining process as soon as you can. If the water forms beads or pools on the surface of the wood, the wood requires additional time to dry.
Is it OK to paint wood that has been pressure treated?
Brushes, rollers, and sprayers are all viable options for painting pressure-treated wood. It is essential that the wood be completely dry before painting it, both on the surface and within. The ideal paint to use on pressure-treated wood is an exterior latex paint of excellent quality that is water-based, and it should be used in conjunction with a primer of the same type.
