Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
Many homeowners want to find out whether their homes are made of pressure-treated wood. This information can help determine your home’s value, safety, and what materials to buy for your repair/remodeling projects.
Most homes have parts made of pressure-treated wood. Most commonly, pressure-treated wood is used for framing, decks, joists, subflooring, and other parts of a house where moisture and insect damage may be an issue. In some states, using this type of wood is part of building codes.
Keep reading to find out which parts of your home are most likely to be built with pressure-treated wood, how to know whether your home is built with it, and why it’s important to know.
Are Homes Constructed With Pressure Treated Wood?
Most American homes have parts made of pressure-treated wood, even though it might not seem like it. This type of wood is commonly used on home exteriors, where untreated wood wouldn’t cut it due to exposure to moisture and other weather elements.
So if you have a wooden deck, walkway, accessibility ramp, or fencing, it’s likely that it’s built with pressure-treated wood.
Your bathroom subfloor panel may also be made of pressure-treated wood due to the extra exposure to moisture. And if you live in Hawaii, the US Gulf Coast, or any other area where termite infestation is an issue, the sill plates (or even the entire structural shell) may be made of borate-treated wood.
Some homes also have foundations made of pressure-treated wood. These types of foundations are known as Permanent Wood Foundations (PWF) and are commonly used in areas where concrete is too expensive.
PWF systems typically comprise load-bearing wall systems usually framed and sheath with pressure-treated wood and plywood, respectively. In fact, using pressure-treated wood is a part of compliance with PWF building codes and standards.
Speaking of codes and standards, using pressure-treated wood in certain parts of your home is a regulatory requirement in some states. The framing is a perfect example of such parts. In most states, any framing that touches the foundation must be made of pressure-treated wood.
Other parts where the use of pressure-treated wood is commonly required for building code compliance include:
- Areas that are in direct contact with the earth. E.g., ground-hugging decks.
- Parts where wood directly rests on concrete or another masonry.
- On retaining walls.
- On wood house siding.
- On joists and subflooring.
- On certain parts of exterior masonry walls.
Of course, specific state code requirements on this topic vary greatly. Some states have strict requirements for where pressure-treated wood must be used in a home, while others like Hawaii, Arizona, and Alabama (just to name a few) don’t have building codes, to begin with.
That means the allowed and required uses for pressure-treated wood vary, too. Since outlining each state’s requirements in this regard is beyond the scope of this discussion, you’ll need to consult with an architect, a building enforcement officer, or a contractor to find out what rules apply in your area.
How To Know if Your Home Is Built With Pressure Treated Wood
The first thing you’ll need to know is how to identify pressure-treated wood. Fortunately, that’s easy because pressure-treated wood usually comes with end stamps/tags that denote the type of chemical used in the treatment process.
This type of wood may also have a brown or green color, usually from the treatment process. Lastly, it has an oily, “chemical” smell instead of the natural smell typically found on untreated wood.
Having understood what you’re looking for, the next step is to know which parts of your home you need to check. For that, I’ll refer you to the above section, specifically to the parts of a home where American homeowners are commonly required to use pressure-treated wood. These are the areas you want to check if you’d like to determine whether your home was built with pressure-treated wood.
Why should you care whether your home was built with pressure-treated wood? Here are the two reasons:
To Observe Building Codes During DIY Repairs/Remodelling
You don’t want to violate building codes when remodeling or performing repairs. If you find pressure-treated wood on certain parts of your home, there’s a good chance it was chosen as part of building code compliance.
So when you’re remodeling or repairing those parts, you’ll want to stick to that type of wood because failure to do that may tamper with your home’s structural integrity, posing safety and health risks. It can also lower your home’s value or even prevent a potential sale in the future, not to mention potential fines and charges.
To Ensure Your Health and Safety
Safety is arguably the biggest concern people have when they go out of their way to find out whether their homes are built with pressure-treated wood. The main question is whether this type of wood is safe for indoor use.
While pressure-treated wood is generally considered safe indoors, it isn’t appropriate in some parts of your home. Specifically, it’s not recommended for cutting boards, countertops, or other parts where it can easily come into contact with food.
Whether pressure-treated wood leeches harmful chemicals into interior spaces is still open to debate. Some people think it does, while others don’t. According to the Environmental Protection Agency (EPA), the toxicity of pressure-treated depends on the preservative used.
One thing’s for sure, though; you don’t want to use Chromated arsenicals (CCA) treated timber, whether it’s indoors or outdoors. Due to suspicions about leeching small amounts of arsenic from its surface, CCA-treated wood has been discontinued from residential use since 2003.
But while its production stopped then, many homes built before 2003 (and some built-in 2004) have CCA-treated wood. If your home was built around that time, you might want to have an inspector check it out.
Most homes have parts made of pressure-treated wood. This type of wood is used in various parts of many homes in the US to beef up structural integrity and ensure compliance with building codes and standards. Most commonly, you’ll find it on parts of a home that are predisposed to moisture and insect damage.
Finding out which parts of your home are built with pressure-treated wood can help ensure your health and safety, as well as building code compliance when remodeling/performing repairs.
- The Spruce: Pressure Treated Wood Code Requirements at Home
- Pro Wood: Is Pressure-Treated Wood Safe for Indoor Use?
- EPA: Can you build a house out of pressure treated lumber?
- Deck Bye E3: To Build a Ground Hugging Deck
- Construction Specifier: What the 2015 International Building Code Means for Wood Construction
- Wood preservation Canada: Building Code Requirements
- Popular Mechanics: 7 Building Code Violations You Should Definitely Avoid
- EPA: Chromated Arsenicals (CCA)
- EPA: Overview of Wood Preservative Chemicals
- American Wood Council: Material
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