Pressure treated lumber is popular to use in decks and playhouses. It's inexpensive and easy to find. If you are considering using this in your next outdoor building project, here are a few of the benefits and disadvantages.
Pressure treated lumber is far cheaper than standard hardwood. The pressure treatment infuses the wood with chemicals that prevent decay from moisture. Pressure treated lumber also won't be damaged by insect activity, and resists mold and mildew more readily than non treated wood. You can also expect the lifespan of pressure treated wood to far outlive that of wood that isn't treated.
While pressure treated lumber does have it's advantages, it also creates some concerns. Most pressure treated lumber contains traces of arsenic, a compound that is known to be a carcinogen. While the companies that produce this lumber will assure you that the chemicals are locked in to the wood, if it burns these toxins are released in to the air. It also creates leaching when used on ground levels, and you can find trace amounts of arsenic in nearby flower beds or vegetable gardens. Repeated exposure can create problems. If you decide to tear it down years down the road, disposal is not easy, and many landfills won't accept pressure treated lumber.