There are many good reasons why wood is pressure treated, which involves the procedure of it getting soaked in chemical preservatives. We instinctively tend to get worried about health and safety when we hear the word chemicals, and it’s not unjustified.
There is no doubt that pressure-treated wood has its benefits; it modifies wood to become durable, tough, and resistant to termites and other pests, making it an excellent option for building outdoor structures like bridge decks, sheds, etc. However, in most cases, it isn’t a safe option to have it indoors in your house. There are potential health hazards that it might pose; thus, it is crucial to understand how to tell which wood has been pressure treated and how to utilize that information to your best advantage.
How Do You Know if Wood is Pressure Treated?
Following are eight different ways to determine if your wood is pressure treated or not. You may either just use one of them or more to verify and examine your lumber properly.
1. Check for an End Tag
As mentioned above briefly, treated wood is generally injected with chemicals, which means that typically most pressure-treated wood is end-tagged with information about the chemical preservative used, it’s rating, and the company that handled it.
This end-tag is usually glued or stapled to the cut end of the lumber and will give you all the information that you need about the lumber in question.
A chemical you should avoid at all costs is a now prohibited chemical your indoor wood use called Chromated Copper Arsenate (CCA). It is known to increase the risk of getting cancer.
2. Get the Fact Sheet
If you weren’t able to get your hands on the end tag for some reason, you could always ask whoever you are purchasing the wood from for a fact sheet.
The information contained in a fact sheet is pretty much the same as what you would find on an end-tag, so you should be able to get all the answers that you’re looking for.
3. Find the Stamp
Stamps are another way of knowing if your wood has been pressure treated or not and what kind of chemicals were used; that’ll help you decide how safe it is to use and for what purpose. These stamps are generally found on the face of the lumber, clearly visible.
Again you’ll have to stay clear of woods treated with arsenic, such as CCA, L P22, and L P2. Instead, opt for the safe ones with stamps of FDN, Bor, Hi Bor, and/or Tim Bor. FDN stamped lumber is intended to be used as foundation material for buildings’ flooring base, while Bor, Hi Bor, and Tim Bor are supposed to be used indoors.
Though it can resist termite infestation, it isn’t moisture-resistant; thus, it is not a good idea to use outdoors.
4. Check the Color
First, look closely at the wood to inspect if its grooves have a green or olive color/ tint to them. If they do, it is very likely that the wood has been pressure treated.
Another thing you may also do is, cut into the wood to distinguish the inside color of it. If you see grey, then it’s normal untreated wood going through the normal process.
5. Do the Smell Test
Whenever we aren’t sure about what we’re seeing or are not able to see clearly with our eyes, our next thought is to use our nose and smell; that’s precisely what you should do in this case. Pressure-treated wood often has a noticeable chemical or oily stench instead of the natural, earthy smell it should have.
Please take note that CCA-treated lumber would not have any distinctive smell, so if you suspect that the wood you’re dealing with is older than 2003, it’s better to skip this method and just use one of the others.
6. Lumber Dimension
Chemical injected wood is oftentimes more in width as opposed to regular lumber.
This is due to the fact that when the wood is soaked in chemicals, it expands, so if you check the width of your wood and it’s thicker than what regular cut lumber pieces used in buildings and construction would normally be, then it most likely has been pressure treated with chemicals.
7. Find the Retention Level
You’ll be able to find this information on the end tag, fact sheet, or even on the stamp that’s on the lumber itself. Alternatively, ask the person who sold you the lumber or whoever is handling it what the retention level of the wood is.
Retention levels refer to the number of chemicals that have been injected into the wood. This information will help you determine how to use the lumber and how durable it is. Generally speaking, the higher the retention level, the longer it will last.
However, keep in mind that the number will be somewhat affected by the type of wood species in question.
8. Use a Swipe Test Kit or Wood Testing Kit
These kits are straightforward and easy to use; you’ll find that they’re mobile in nature as well. You may find these kits on the internet for a reasonable price.
These kits will help you determine whether or not the wood has been pressure treated and if it is arsenic-free. You may also be able to find these kits in some commercial labs; if not, you can always order one online.
Advantages of Pressure Treated Wood Over Regular Lumber
There are many undeniable benefits of using pressure-treated lumber over regular wood, which has made it a desirable choice for many homeowners, carpenters, and even landscapers. The advantages of pressure-treated wood are as follows:
It’s moisture and fire-resistant
This type of wood is excellent for outdoor use in areas exposed to wind, rain, or snow. Its moisture and fire resistance makes it ideal for building porches, decks, fences, and other outdoor structures. It is less likely to warp or crack than untreated wood.
It’s resistant to fungus, insects, and rot
The chemical preservative used in pressure-treated wood protects it from fungus, insects, and rot. This makes it an excellent material for indoor and outdoor landscaping projects.
It’s able to last long in good condition, with rare easy and cheap repairs
As mentioned before, pressure-treating wood makes it durable. With proper care and maintenance, it can last for decades. It is easy and affordable to repair if it does start to show signs of wear and tear.
It is affordable
Redwood and Cedar are two popular choices for outdoor projects. They are both beautiful and have natural rot resistance. However, they are also some of the most expensive types of lumber. Pressure-treated wood is more affordable, making it a great choice for many projects.
Safety Recommendations While Checking Pressure-Treated Wood
There are a few safety recommendations that you should keep in mind while checking pressure-treated wood yourself. Pressure-treated wood often contains arsenic and other chemicals, so it’s essential to take the following precautions:
Wear protective gear
When checking pressure-treated wood for signs of wear, it is essential to wear gloves. This will protect your hands from the chemicals that may be present in the wood. Also, when cutting pressure-treated wood, it’s important to wear a dust mask. This will help protect your lungs from the harmful chemicals that may be present in the wood.
Wash your hands
After checking the pressure-treated wood, be sure to wash your hands thoroughly with soap and warm water. This will help remove any lingering chemical residue left on your hands from the wood.
Cut wood Outdoors
If you need to cut pressure-treated wood, it’s best to do it outdoors, where there is proper ventilation. This will help minimize your exposure to the chemicals that may be present in the wood and prevent any harmful dust or fumes from spreading indoors.
Bleach is frequently used to clean wood and give it a lighter appearance. However, it’s important to use mild bleach, such as a non-chlorine bleach, for cleaning pressure-treated wood. It is recommended to be very careful and wear protective gear while doing so to minimize your exposure to the chemicals in the wood. Stay away from chlorine bleach and instead use a mixture of oxygen bleach and water.
It is not recommended ever (or even allowed in some countries) to burn pressure-treated wood under any circumstances, as it can release very harmful chemicals into the air. If you need to dispose of pressure-treated wood, it is best to dispose of it at a hazardous waste disposal site.
Allow It To Dry
Pressure-treated wood must be allowed to dry out for a long period of time due to the large amounts of chemicals that have been injected into it. If you are going to stain or paint it, allow plenty of time for the wood to dry before beginning your project. (This can take up to 6 months.)
Pressure-treated wood could also be dried in a kiln. It is the fastest and most dependable technique for drying pressure-treated wood. Additionally, you should be careful when storing pressure-treated wood, as it often should not be stored near food or on the bare dirt ground.
Dos and Don’ts Of Using Pressure Treated Wood Indoors
Now that you know some of the basics about pressure-treated wood, here are a few dos and don’ts to remember when handling it:
- When working with treated wood, use gloves, and wash your hands thoroughly before eating or drinking.
- When cutting, drilling, or sanding, always use safety glasses and a dust mask to avoid inhaling wood particles or chemicals.
- Don’t forget to tidy up after yourself. Always gather any sawdust left behind from sanding or drilling and dispose of it properly.
- Don’t use treated wood indoors unless it is labeled for indoor use. The chemicals in the wood can be harmful if inhaled or ingested.
- Pressure-treated wood should not be used on surfaces that often contact food, animals, or people since it emits harmful chemicals. For example, you would not want to use pressure-treated wood for a cutting board, dining table, or bed frame.
- You should stain or apply any other finishes to exposed treated wood to provide a protective barrier against the chemicals.
- Treated wood needs to be fully dry before staining or painting. Sprinkle the wood’s surface with water to test its dryness. If the water forms beads, the wood is still wet, and you must wait for it to dry. However, if the water penetrates the wood, it’s ready for stain or paint.
- If you don’t want to stain or paint the wood, use some clear wood preservative once a year to keep it in good condition and help it last longer.
- Before drilling a nail or screw into wood, make sure to drill a pilot hole to avoid the wood from splitting.
- Don’t recycle commercial wood products, such as utility poles, which are likely to include harsh chemicals. Check with your local waste management authority for advice on how to recycle wood that has been treated with chemicals.
- Treated lumber will shrink somewhat over time as it dries out. When laying decking or fence boards, take this little amount of shrinkage into account when placing them.
Pressure-treating wood has been around for many years and is a popular way to make it more durable and weather resistant. If you are using pressure-treated wood, take the proper precautions and follow the dos and don’ts to avoid any harmful effects.
With a little bit of care, your pressure-treated wood should last for many years.
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Lawrence D. Reynolds is an experienced carpenter and woodworker who started this site to help others get into this craft by providing advice on choosing tools and materials and sharing How-To guides about woodworking. He has been into Woodworking for over 25 years and enjoys nothing more than sharing his knowledge and helping others learn about this wonderful material.