Evolution Of Pressure Treated Decking
Do You Know You Have Choices?
It's true. The pressure treated decking market has changed a lot the last ten years and continues to see new solutions.
Since at least 1940, CCA was the preservation standard for outdoor
wood. Then in 2004 the industry moved to phase out CCA (chromated
Goodbye CCA, Hello ACQ
But concerns of leaching and human exposure to arsenic in residential environments caused a major change.
Everybody switched over to ACQ (alkaline copper quaternary) which
was safer but caused corrosion of many standard metal fasteners and
It can still leach out but the arsenic has been removed so it's no longer the same worry.
But this change led to people paying more so use stainless steel
hardware or heavier zinc coatings to avoid that problem. ACQ leaves a
very deep green tone to the wood which is unmistakeable.
And Now, There Are More Options
There are two new and exciting pressure treating options for decking
boards. MCA (micronized copper azole) and Thermal Treating are solutions
Pressure treated lumber from the MCA process has a number of improvements.
Firstly, it's not so noticeabley green. Lumber treated this way is
only slightly darker which is a nice cosmetic benefit. A much more
natural look to the decking.
The copper used in this process is much smaller and also water
soluble. This means the copper preserving particles can penetrate much
deeper into the wood rather than sit on the surface.
Deeper penetration also means far small chance of it leaching out.
But what is really great is you can use regular galvanized hardware
and connectors. You don't need extra zinc coating or more expensive
So look for this on the market. Here is one place you can find it.
This is a very promising new way to make pressure treated decking.
The concept is to heat the wood and kill all the sugars in the wood that bugs and bacteria love to feed on.
No food. No decay. That's the theory.
But it's a three stage process and various temperatures that uses a
fair amount of energy to do and so that raises the cost of the treated
decking boards to about the price of the higher end composite decking.
It is positioned in the market as a higher end decking material and for good reason.
The boards don't absorb water because one of the chemicals needed
for water to adhere to is removed. This keeps the treated decking boards
very stable. Twenty five year warranties are offered by this company.