Pressure treated wood can easily withstand rain, sun, and other elements. You have proven this with your deck made up of treated wood. Thus, you prefer to enjoy the same durability indoors.
As fellow homeowners, we want our wood projects to last long, tough, and functional. Yet, the same chemicals that make treated wood reliable have got you worried.
Can you use pressure-treated wood indoors? What precautions should you take to make sure it’s safe to have these in your home?
In this post, we’ll talk about pressure wood – how to tell it from untreated lumber aisle, the preservatives used, is it safe for indoor use, and some tips to make it so, and which project treated wood suits best.
What is Pressure Treated Wood?
Pressure treated lumber is wood that has undergone pressure treatment. In it, wood is placed in a pressure chamber full of liquid preservative chemicals.
To double-check, if the wood is pressure treated, look for half-inch long splits on all surfaces. This is where pressurized chemicals were injected. Treated lumber usually has a greenish tint or dark brown color.
Chemicals used in the wood are fungicides and insecticides. Manufacturers have developed safer alternatives through the years. Chemicals leaching is deadly to insects and fungi but non-toxic to animals and people.
Can you use Pressure Treated Wood Indoors?
Yes, you can use pressure treated lumber indoors for any interior application except for surfaces that directly contact food, such as cutting boards and kitchen countertops, and where pets can chew it. Chemicals in the treated wood won’t leach on the surface; thus, it’s safe indoors.
Types of Preservatives Used
Chromated Copper Arsenate
Wood with a greenish color was infused with copper, chromium, and arsenic or CCA.
CCA was the most effective substance. It kills fungi, termites, and other pests. CCA wood, however, is poisonous to people and the soil.
Copper Azole (CA)
Wood with CA is colored brown. It has little to no odor. It can either be Type A that has copper, boric acid, and tebuconazole, or Type B, with more copper and tebuconazole but no boric acid.
CA effectively provides mold resistance, fungi, termites, and other insects.
Alkaline copper quaternary or ACQ contains copper and a quaternary ammonium compound. ACQ prevent decay, insect infestation, termite infestation, and fungi. It is ideal for structural support such as Borate.
With the blue dye used during the pressure treatment, thus it’s easy to identify borate-treated lumber. It protects from fungus, termites, and other wood-decomposing organisms.
This makes the blue color wood ideal for indoor use, as wall paneling, ceiling joists, trusses, and millwork. However, don’t use outdoors as the preservative may contaminate the soil.
Oil Based Preservatives
Oil-based preservatives include creosote, pentachlorophenol, and copper naphthenate. These smell oily but are ideal as utility posts and for structural supports such as piling and laminated beams and railroad ties. You can see them with their noticeably dark shade.
How to Tell Wood was Pressure Treated
Easily spot treated wood by looking for these tell-tale signs:
Look for an End Tag
Pressure treated wood has an end tag like this should identify the preservative used, the rating and preservation company.
Avoid using any wood that was treated with Chromated Copper Arsenate (CCA). This preservative includes a form of arsenic. This is why these have been prohibited for use in decks, playgrounds, and similar structures in an outdoor-residential setting since 2003.
Find the Stamp
A stamp should tell you the type of wood and where you should use it.
For instance, If it says “FDN,” which stands for foundation, it is one of the safest types of pressure-treated wood. Builders sometimes use these as the frame basements underneath home flooring.
Equally safe is wood treated with borate. This is ideal for use inside the home as these are safe for people. These have the stamp Bor, Hi Bor, or Tim Bor.
This is ideal for use indoors, as it’s protected against termites. Outside, it’s rot-resistant, and its preservative wouldn’t get into the soil.
Avoid lumber stamped L P22. These have been treated with arsenic. Wood with an L P2 stamp, on the other hand, is less toxic but not safe for home furniture.
Get a Fact Sheet
A fact sheet contains the list of chemicals used in wood pressure treatments. If these include Copper and Tebuconazole, it has undergone pressure treatment.
Check the Color
Each wood preservative has a distinct hue, as mentioned in the previous section.
Do the Smell Test
Pick up the chunk of wood and take a deep sniff if you can’t spot a blue, brown, or green tint. Treated wood smells like oil or extremely toxic chemical components, except for CCA treated, with no distinct smell.
Most lumber for residential construction measures 8 (244 centimeters) to 16 ft. (488 cm).
Some 2x4s and 2x6s sold as precut 92 5/8” long options, which is a standard length of wall paneling.
Wood injected with chemicals is usually a little bit wider and thicker than regular wood. This is because of the wood’s chemicals.
Use a Swipe Test Kit or Wood Testing Kit
Many commercial labs offer a swipe test kit that can identify treated wood.
Find the Retention Level
The retention level tells you how many preservatives were left after the pressure treatment. The higher the retention level, the more durable the wood.
Is Pressure Treated Wood Safe?
Yes, pressure treated wood is safe. It’s safe as material for plant boxes and most houses. Please don’t use it for surfaces that have direct contact with food. Outdoors would be picnic tables; indoors, the chopping boards and kitchen countertops and places where pets can reach and chew it.
The chemicals used are safe for people and animals. Moreover, the pressure treatment process ensures the chemicals won’t leach out and reach the surface.
What you Need to Handle Treated Wood Safely
Given that pressure treated wood has preservatives to make it rot-, insect-, and fungi-resistant, you shouldn’t hold, cut, and fasten it with plain clothing and your bare hands.
Best to exercise caution as the chemical seepage is a skin, nose, and eyes irritant. Here’s what you’ll need to handle treated wood safely:
1. Gloves and long sleeves – safe not to touch because the wood is a skin irritant.
2. Safety goggles and face mask – it also irritates the nose, and sawdust is toxic. Avoid inhaling the dust that can cause colds, asthma, respiratory tract infection, and bronchitis,
3. Vacuum –so you can gather the sawdust and dispose of it properly. Inhaling sawdust and handling cuttings is dangerous. Inhaling can cause colds, asthma, and respiratory tract infection. Touching cuttings will irritate your skin.
4. Disposable plastic tarp – put this on the floor of your work area so it will be easy to gather cuttings and sawdust.
Tips to Safely use Treated Wood
Always exercise caution when you’re around treated wood. Be mindful of the chemicals within the wood that can affect your health when you’re measuring, cutting, and fastening the lumber.
Here are our tips:
1. Wear safety gear at all times when handling pressure treated wood.
2. Have ample outdoor space – don’t work on treated wood indoors. You’ll need the space to avoid inhaling and having direct contact with the lumber.
3. Wash hands with both water and soap after handling treated lumber.
4. Wash separately the clothes you wore when you’re done handling treated lumber.
5. Gather as much sawdust and dispose of it as recommended by Environmental Protection Agency. This is to prevent inhaling the same.
6. And in case you have excess lumber or unused telephone poles, don’t burn them. This will release the chemicals into the air and produce toxic ash harmful to people, plants, and animals.
7. Dispose of treated lumber in accredited landfills that know how to handle them properly.
8. Note that most treated lumber will shrink when it dries out. Consider this when building a deck.
Can you use Pressure Treated Wood Indoors?
As mentioned, treated wood is suitable to be used for other outdoor projects as well as indoor projects. Others might think it’s unnecessary to do so as the lumber wouldn’t be as exposed to the elements as outside, but it’s still better if you can count on the lumber to be reliable, rot- and insect-resistant.
Dangers of using pressure treated wood indoors
Here are some pressure treated lumber indoors hazards:
1. Treated wood is highly flammable. This is because of the chemicals therein. Thus, keep it far away from a flame source (i.e., stove, candle).
2. Chemicals may escape from splinters. This is a possibility but unlikely. Leaches are more likely to occur when the wood is engulfed in soil.
3. Being poisoned is possible when you constantly breathe in or touch wood. Thus, don’t use it in projects that have direct contact with people and animals. There’s, however, no evidence that treated wood affects indoor air quality. This is especially true when the wood is used as structure for the house and not exposed.
Other than being highly flammable, it’s safe to use modern pressure treated wood indoors. Make sure there’s no direct contact with people, the soil, and animals.
Which type of pressure treated wood is safe indoors?
Although all are safe when used properly, Wood treated with borates or micronized is safe to use indoors. Borate wood has naturally occurring minerals that protect lumber against termites, fungi, and rot. It’s recommended for an indoor project.
Where can you use treated wood indoors?
Using borate as a preservative is a primary way on how to treat wood for indoor use. You can use borate-treated wood as interior trim, studs, sill plates, joist, rafters, and trusses.
It can also be used for structural framing and sheathing roof rafters, moldings, beams, blocking, trusses, flooring wood trim, and furring strips.
When Not to Use Treated Wood
We have always advised caution in using pressure treated wood inside the home because of the danger posed by the chemicals used in treating the wood.
But it can be used indoors for some applications. If you have some doubts, here is a list of instances where you shouldn’t use treated wood.
Around babies and children
Treated wood shouldn’t be sniffed or inhaled constantly, or ingested. Thus, when you have young ones in the house, best to stick to non-treated wood.
A good alternative is to use Cedar indoors. You may want to read our cedar vs. pressure-treated wood comparison to learn more.
In the same vein, treated wood shouldn’t be used around pets. Add to the danger of being inhaled and ingested. You have to consider that cats may put their claws in the wood. They may dip their claws into the toxins.
On surfaces that may come in contact with food and water
For people, the primary reminder is not to use treated wood on surfaces with direct contact with food and water. These include your cutting boards and kitchen tables. Food may absorb the chemicals, posing a danger of ingesting the same.
Can you use pressure treated wood for interior framing?
Yes, you can use pressure treated wood inside for framing. Framing material with pressure treated lumber, however, would cost more, and the wood is heavier. The wood preservative may prove unnecessary as the siding, sheeting, roofing already protects the wood from getting wet and acquiring fungus and rot.
Can you paint pressure treated lumber
Yes, you can paint treated lumber. However, if the wood has been treated chemically with chromate copper arsenate (CCA), it should be cleaned before being painted. Use oil-based acrylic rather than water-based paints or stains to prevent the chemicals in treated wood from being affected by water-based paints.
Read When can you paint pressure treated wood to avoid any consequences of painting too soon.
Is pressure treated lumber toxic?
Yes, pressure treated lumber is toxic. The chemicals used are fungicides and insecticides. But these are inside the wood, and there’s no danger in these rising onto the surface. To safely use treated wood indoors, these shouldn’t have direct contact with food and water and where pets and children may inhale, test, and chew it.
Can you use pressure treated wood for indoor furniture?
Yes, you can use pressure treated wood for indoor furniture and indoor projects such as sill plates, for carbon steel fasteners. The only exception is in places where it comes in direct contact with food and water, such as cutting boards and kitchen countertops, and places where pets can chew and ingest the wood.
Can you use pressure treated wood for wall studs?
Yes, you can use pressure treated wood for wall studs. Pressure treated wood is safe to use indoors, except for surfaces in direct contact with food and water and spaces where pets can ingest it.
Can you use pressure treated wood in bathrooms?
Yes, you can use pressure treated wood in the bathroom. Chemicals that protect the wood from moisture, molds, and water damage make it ideal for bathrooms. Don’t use it on surfaces where people have direct contact with it, such as countertops. You can use it to make a bathtub caddy or a shower bench.
Can you use pressure treated wood for dining tables?
No, you cannot use pressure treated wood for dining tables. It is granted that you can put a table cloth and placemats. Still, there’re times you’re going to remove these. It’s still possible for food to have direct contact with the wood. It’s too great a risk. Choose untreated wood for this.
How to pressure treat wood at home
1. Purchase a borax-based chemical treatment solution from your home and garden supply stores.
2. Read the instructions carefully.
3. Put on safety gear such as gloves, safety goggles, and a face mask.
4. Apply the solution over the entire wood surface with a paintbrush or a garden hose spray adapter (if the solution you have can be mixed with water).
5. Let the wood dry for 24 hours. Best to repeat the procedure for extra protection.
Can you use pressure treated plywood for the bathroom subfloor?
Yes, you can use pressure treated plywood for bathroom floors. A bathroom subfloor is subject to a lot of moisture, and with pressure treated wood being a moisture barrier, it’s ideal for this purpose. It’s okay to use pressure treated wood, as long as the wood doesn’t come in direct contact with people, plants, and animals.
Is brown pressure-treated wood toxic?
Yes, brown pressure treated wood is toxic. Pressure treated wood that has a noticeable brown color was treated with micronized Copper Azole (CA) or alkaline copper quat (ACQ). CA and ACQ are fungicides and insecticides. But they are safe as long as they don’t come in direct contact with food and water, inhale and burn them.
You can use pressure treated wood indoors. Pressure treatment ensures that chemicals remain in the wood. Feel free to use them and benefit from the durability of the wood. So, no need to worry. The only exception is that you can’t use treated wood on surfaces in direct contact with food, people, and animals. Remember that the chemicals used to treat wood are insecticides and fungicides.
Treat them, so you don’t put yourself, your plants, family, and pets in danger. Now that you have learned how to use treated wood indoors, let’s talk about using non-treated wood outside.