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C R O S S C O U N T R Y F I V E - W A L L S E R I E S S T R A I G H T L E A N T O • G R E E N H O U S E I N S T R U C T I O N S
Pressure Treated Wood
WHAT IS NEW ABOUT PRESSURE TREATED WOOD?
As of January 2005, the chemicals used in pressure treated wood have been changed. Previous
wood was treated with arsenic. However due to the potential long term health hazards this has
been discontinued. New pressure treated wood is treated with copper.
The copper in the ‘new’ wood will be CORROSIVE TO ALUMINUM as well as other metals.
What are ‘Greenhouse Friendly’ solutions to the new pressure treated wood?
1
If you are using the new pressure treated wood, you must place a barrier between the wood
and your aluminum frame. Popular barriers include 10 mil thick plastic sheeting, steel
weather flashing, a rubber or foam weather membrane, or a row of weather resistant non-
treated wood such as cedar or hemlock.
2
Other weather resistant non-treated woods are popular alternatives to pressure treated wood.
These contain no harmful chemicals and will outlast pressure treated wood. Cedar timbers
are a popular choice for greenhouse foundations.
3
Concrete foundations have always been suitable foundation alternatives for greenhouses.
They can vary from poured concrete slabs, poured concrete perimeter walls to concrete block
walls. Although these are usually more costly than wood alternatives, they have the benefit
of lasting a lifetime. As they are usually considered a permanent foundation, it is important
to check with your building codes to determine what you are able to build.
If you have any questions about using the ‘New’ pressure treated wood in conjunction with our
aluminum greenhouses, please contact our office at 1-888-391-4433.