Just got a 10' x12' x 10' height polycarbonate greenhouse with aluminum structure kid for the wife:
A number of years ago I assembled two small glass greenhouses. They were similar to the polycarbonate, but cheaper. They had similar instructions and even though the glass has weight, I wasn't comfortable with the things just sitting in gravel. I actually excavated a small trench and laid two tiers of
6x8 pressure treated ties, as a foundation, then screwed the frames to the tops of the ties. It worked out real well
The chemicals in the new pressure treated wood eats up steel even galvanized in no time and I wonder how the aluminum would react to this new stuff. Might just bury the whole thing in a concrete slab but I have no knowledge on how aluminum would react to concrete either say over a 15 year period.
Thanks, you save me a lot of trouble down the road.
Aluminum is worse. Hot dip galvanized is rated for contact, but aluminum is not. The porch stanchions I just put in came with heavy plastic pads to isolate the base if you are using pressure treated wood, and stainless steel lag screws. So you could go that route with an isolation pad wherever they touch.
Suggest using the screw in auger type anchors at the corners and securing down to them with something like small turnbuckles. Should be sufficient to keep the thing from blowing away in one piece. A strong enough wind would pretty much tear the thing apart before it would pull the anchors anyway.
How do you like that greenhouse anyway? I've been really tempted to get one myself.
Pete C.
The 5 inch base is steel and the aluminum greenhouse frame connects to it with clips at each post. I used 4x6 treated lumber as the foundation then connected the base to it with Stainless lag screws every 2 feet. I also put a strip of Sill Seal between the base and the treated wood. If you have any wind or snow load you will need to spend another 100 to 200 dollars on reinforcements. You can find a lot of information on how different people built theirs on the greenhouse forum on Gardenweb.com . At a minimum screw in the panels so they do not blow out and add a rafter or two to handle snow loads and give you someplace to hang plants from.
Bill
I haven't install it yet. Got it on sale and on top of it with a 15% off coupon - what a bargain. Millions of parts in one huge 7'+ long 200 lb. box. Surprised they could cramp a 10x12 structure is just one box.
I just found out about the Gardenweb.com from the people at rec.gardens yesterday. Checkout the instructions and pictures on structural modification against wind loading - do a HFGH search in that website. I'm debating on either a concrete foundation or granite slabs.
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