greenhouse construction aluminum sides on concrete

[amstutz1]

I am assembling a new greenhouse and the company who built the greenhouse recommend attaching the aluminum base rails directly to my concrete block base. My friends tell me there will be corrosion if I do not put down a plastic or other barrier. Any opinions?

[Ray]

There will likely be some chemical reaction between the basic chemistry of cement and aluminum, but if you consider that aluminum is anodized by immersion in sodium hydroxide - giving the metal a very protective layer - I doubt it would be an issue.

Besides, I suspect you'll be putting a layer of silicone caulk to seal the joint anyway, so that will provide some separation, making the question mostly moot.

[amstutz1]

Ray:
Thanks! One of the guys helping me put this think up is adamant the thing will fall down within ten years if I do not install a plastic sheeting barrier. I agree with you.
Mike Olmstead
Harrisburg, PA