Treated Wood Lumber Professional-Level information and how-to-build articles for wood, timber, and lumber professionals and users. Treated Wood » Lumber Talk
By Chris | November 11, 2013 - 12:17 pm - Posted in Specs & Data, Treated Wood

There’s a common question that gets batted around. The answer is simple but the reason is usually not explained well. Feel free to add your 2 cents, too, if you happen to be a chemist or treated wood pro.

Can you burn treated wood? Well, yes. You should know it is illegal in all 50 states to do so.

SHOULD You Burn Pressure Treated Wood?

NO. You should not burn pressure treated wood — ever. Again, it is illegal in all 50 states to burn pressure treated wood.

Why You SHOULD NOT Burn Treated Wood?

First, it’s illegal. If by some chance it is not illegal where you are, it probably should be. Second, the metal left in the ash is probably harmful to you or the environment in one way or another. For the purpose of this post, we’ll focus on 3 chemicals commonly used to pressure treat wood.

  • CCA — Chromated Copper Arsenate — only used for commercial and marine applications now
  • MCQ — Micronized Copper Quaternary — used for residential and commercial
  • CA — Copper Azole — use for residential and commercial

The primary ingredients in these pressure treated wood chemicals are metals — copper, chromium, and arsenate (a form of arsenic, in case you were wondering). When treated wood is burned, the metals remain in the ash. Inhaling the smoke would be bad for you, too, but the main danger comes from the concentrated metals left in the ash.

All three metals are toxic to some degree. Arsenic is the worst, by far. According to this discussion string, the ash left from burning CCA treated wood is toxic enough to kill cows and deer.

Copper and chromium are also toxic but not so severely poisonous as arsenic. The human body needs some copper to function properly but too much lead to a host of issues from diarrhea and vomiting to liver failure and more. Here is a list of possible reactions to copper toxicity and some more here. Chromium poisoning appears to be pretty terrible, too.

Chromium poisoning is very rare but it is possible. Chromium is an essential nutrient in the human body and helps with how insulin regulates blood sugar levels. Too much can cause rashes, renal failure, and more.

There you have it. The short answer is DON’T BURN TREATED WOOD but the readers of LumberTalk tend to like more complete info so there you go. Here’s a post where someone posts the question about why it’s so bad to burn treated wood. The responses are aggravating because no one answers his question and only tells him to trust in knowing that it’s dangerous. You might actually feel a little sorry for “tgm1024.”

By Chris | May 13, 2011 - 4:50 pm - Posted in Treated Wood

green treated cca poles

These "Green Treated" poles have a light green color because they are treated with CCA

A lot of people ask about “green treated wood.” There’s nothing magical about it so let’s clear it up.

Green = CCA

9 times out of 10 green treated wood simply means CCA treated wood. CCA, of course, is Chromated Copper Arsenate, the stuff that was banned for use in most residential applications such as decks, railing, fences, and the like.

People freaked out about the “arsenate” component of the wood. Arsenate is a naturally-occurring form of arsenic so people got freaked out but the stuff is all around us anyway. Stick your hand in any patch of dirt in your backyard and you’ll probably be touching more arsenate than if you were to do a handstand on your CCA treated deck (which you can’t make anymore). I’ve researched it a decent amount and have seriously never seen any evidence that it actually causes any health issues. Oh, yeah. I digress…

CCA is still allowed for use in water and for many commercial and industrial applications because it is an ultra-effective treatment to dramatically increase the life of wood. Wood treated with CCA gets a green color that might range anywhere from light young-lemony-green with light treatment to near-forest green with a saltwater treatment (2.5pcf).

It’s that simple, really. Green treated wood is wood pressure treated with CCA.

Other Treatments

To separate themselves from the green treated wood, ACQ treated lumber producers branded their ACQ treated wood lumber as Yellawood, which you’ve probably seen on everything from store shelves to billboards. MCQ is basically clear, or colorless. In fact, the very strength of being clear is kind of its weakness, too, because when MCQ lumber is delivered many people do not believe they have received treated wood. It really is that hard to tell sometimes.

CCA is a better product anyway. I think we should drop the Yella stuff and the clear stuff and the whatever stuff and go back to the good ol’ green treated wood that works so well. It makes me want to only build on water where I know I can use the good stuff.

Of course, there’s also BLUE treated wood which is usually a borate-based treated wood but that’s a different conversation. 🙂

By Chris | July 14, 2010 - 4:47 am - Posted in How To, Marine Structures, Treated Wood

On his 4th voyage over to America, Christopher Columbus lost all of his ships to shipworms. All of them. Why was so little wood found on the sunken Titanic when they finally raised it from the ocean floor? You got it…shipworms. You got that right, right?

Mollusks, Actually

So what are shipworms…and why and how do they cause so much damage? Shipworms (also known as Pileworms) actually are not really worms at all, but are rather a type of clam that has very small shells used for boring into wood in saltwater.

A marine bivalve mollusk (with 65 different species)…they get their name for their long, narrow, cylindrical bodies – resembling worms. However, upon closer inspection, you will find a small drill-like shell. This shell has two halves with a gap between them, like a clamshell. In the gap there is a muscular foot that acts as a suction cup, holding the shell in place while it’s razor-sharp edges scrape the wood ahead of it. Shipworms have long tubes that stick out into the water so the worm can breathe, and can also seal the worm in the wood in cases of extended periods out of water…low tides for example.

Up To 6 Feet Long

shipworm (tereda)Also known as “Termites of the sea”, shipworms eat sawdust. The stomach of shipworms has a pouch for storing sawdust and an organ/gland full of bacteria that aide in digesting wood. The bacteria take nitrogen from the water and convert it to protein for the worms’ nourishment. The shipworm invades wood while still in the larval stage, making an entrance hall that is usually too small to see. It uses the shells on its head to burrow. The ridged, rough surfaces rub the wood away as the worm moves from side to side. This cuts away a perfectly circular tube that is just larger than the shell. The wormlike body follows behind the shell, producing a chalk-like substance to line the burrow. As they burrow deeply into the wood, they grow very quickly. As the worm grows, so does the burrow. Depending on the size of their homes, shipworms can range in size from 6 inches to as long as 6 feet.

Expensive Damages

Once a shipworm claims a home, it is there for life. A piece of wood may be infested with shipworm, but they will deliberately avoid each other’s tunnels. Instead they twist and turn their tunnels until the wood becomes a mass of tubes and holes, and eventually collapses. Shipworms are sometimes called the mollusk with the million-dollar appetite. These creatures are credited with single-handedly destroying the Hudson River piers in New York City. Researchers estimate that untreated timbers, such as pier pilings, exposed to Hawaii’s ocean waters will last less than two years.

A Positive Note

However, this incredible appetite has a purpose. Large amounts of wood get into the oceans by river deposits, forests and mostly, humans. Shipworms play an integral role in reducing the amount of driftwood in the world’s oceans.

How To Stop Shipworms

So, how do we stop the shipworms & protect our ships & wooden structures? By protesting at the White House? Not likely. Shipworms don’t like copper….so we can build using copper nails, or even copper sheeting. A cheaper and easier method is simply using CCA treated wood which contains copper (CCA = Chromated COPPER Arsenate).

Well, We Like Oysters

Or, we can eat them. In some places, shipworms are considered a culinary delicacy. In the Philippines, it is prepared as ‘kinilaw’ – eaten raw, with vinegar or lime juice & chopped peppers and onions…Similar to ceviche. The taste has been compared to a very wide variety of foods ranging from milk to oysters.

An industry-changing product is now available in the US. It is “treated” wood without any chemicals. Nature’s Choice Deck, distributed by Building Products Plus, is made of premium grade southern yellow pine, uses no chemicals, and comes with a 20 year warranty.

Think about it – “treated” wood with zero chemicals – 100% natural wood.
thermally modified wood - Nature's Choice

Thermally Modified Wood
Although thermally modified wood has been proven effective in Europe since the mid-90’s, it is new to the US where it took on the brand name Nature’s Choice. Developed in Finland, thermally modified wood is kind of baked (for lack of a better word) until the composition of the wood changes such that it is no longer attractive to termites, fungus, and other forms of decay. Using special kilns, the wood is heated for about a day to just below flash point and cooled using carefully timed applications of water to maximize its strength and longevity.

As Green As It Gets
Nature’s Choice ( is as green as it gets. It is made of easily renewable southern yellow pine from managed forest land and produced in the heart of Amish country in production facilities that use relatively zero electricity. It’s seriously green from start to finish. It contains no chemicals so you don’t have to worry about your gardens, lawn, ground water, or kids. And, finally, since it is long-lasting the wood will not need to be replaced often. However, when you do replace it the wood can be thrown away, re-used, or even burned (unlike chemically pressure-treated wood).

This is the stuff dreams are made of, eco-speaking.

Physical Properties
Its strength is up to par, too. You can cut, drill, nail, screw, and everything just like regular wood. No special fasteners are required but you can use a hidden deck fastener system is you wish. In other words, it is regular wood – except, you know, with no chemicals.

Here are the stats from Nature’s Choice Deck technical info page.

    • Uniformly Darker Color
      Increased Surface Hardness
      Resistant to Decay
      Decreased Absorption of Moisture
      Moisture Deformation Decreased by 30 – 90%
      Splitting Strengths Reduced 0 – 50%
      Bending Strength Changes -15% – +20%
      Resins Dry Out or Evaporate
      Equilibrium Moisture 10 – 50% Smaller than in Untreated Wood
      Overall Increased Stability
      Increased Longevity
  • Beautiful Appearance – Darker Color
    Nature’s Choice is made of premium grade (better than #1) southern yellow pine so the boards are about 100% free of wane and nearly totally free of knots. The faces of the boards are different (one side smooth, the other grooved) and since the wood is so highly selected, the boards are essentially reversible.

    The thermal modification process darkens the wood to a beautiful light-mahogany color. The picture above is unstained pine (really!). See the Nature’s Choice Deck website for more pictures. According to the guys at Building Products Plus, all of the pictures on the site (as of the date of this writing) are southern yellow pine. Hard to believe but see the comparison image here.

    Dimensions & Availability
    Currently, Nature’s Choice thermally modified wood is available in 1″x5″ (actual dimensions) deck boards. They say they will offer more in the future. In fact, they mentioned plans for large timbers made with the stuff and maybe even pilings. Yes, chemical-free pilings. These guys are kind of quietly leading their own green movement.

    Expect to see more Nature’s Choice Deck in the future. People have been looking for this sort of thing and it’s finally here.

    Shortly after it was posted, Claire Guappone of Osmose contacted me regarding “MCQ Shows Signs of Rapid Decay” and asked if I would like to receive a follow up press release on the matter.

    “Sure,” said I. So, here it is.

    Consumer Safety and Product Performance of Micronized Copper Technology Confirmed

    GRIFFIN, Ga., Feb. 11 — On Feb. 9, 2009 in a negative public relations document apparently intended to scare users of treated wood, Charlotte, NC-based Viance criticized the effectiveness of micronized copper wood preservatives. “Viance is once again attempting to create unfounded concerns about consumer safety and product performance, using statistically insignificant and suspect data,” said Paul Goydan, President of Osmose, Inc.

    Extensive laboratory and extended field testing have confirmed the effectiveness of micronized preservatives. Several world renowned scientists have confirmed the strong performance of this technically advanced preservative technology and have published their comprehensive findings, which support the micronized technology’s efficacy in providing wood protection for both above ground and ground contact applications.

    So why this unfounded attack by a competitor? An attack based on an insignificant sample of a few posts selected by this competitor — out of the millions of posts in service? One might conclude the competition has not been able to create a viable alternative product to compete with our patent pending technology and the ever-increasing market penetration of the micronized copper preservative systems. Rather than offering similarly advanced technology, they have resorted to needlessly alarming the public.

    MicroPro(R) Treated Wood Facts:

    • Over 5 Billion board feet of MicroPro treated wood has been sold since the product introduction in 2006.
    • Over 10 Million 4 x 4 micronized treated wood posts are presently in service and performing.
    • MicroPro copper based preservative systems have been independently tested and evaluated in accordance with AWPA, ASTM and other internationally recognized laboratory and field test procedures.
    • Micronized copper preservative systems are certified by the International Code Council Evaluation Service, Inc. (ICC-ES).
    • Osmose’s micronized technologies have earned the Environmentally Preferable Product (EPP) certification from Scientific Certification Systems (SCS).
    • Osmose provides a Residential and Agricultural Limited Warranty on MicroPro treated wood products.

    Bottom Line

    Extensive laboratory and field testing has confirmed the effectiveness of micronized preservatives. International experts have confirmed the legitimacy of this technically advanced preservative technology and published their findings in support of it. Billions of board feet of micronized treated lumber are in service and performing. Since the introduction of micronized copper technology, Viance, the only copper based preservative manufacturer that does not have the micronized technology to offer, has waged a desperate campaign against it in an effort to discredit it. Meanwhile, more and more consumers and retailers continue to embrace the environmental and performance benefits offered by our technically advanced micronized products.

    Since 1934, Osmose has produced quality, tested, reliable wood preservatives such as MicroPro. We fully stand behind our products and back them with industry leading warranties.

    For additional information regarding MicroPro, please contact Osmose at (800) 241-0240 or visit