Just got a 10' x12' x 10' height polycarbonate greenhouse with aluminum
structure kid for the wife:
The instruction is to excavate the area to a depth of 5" and bury the
greenhouse base frame in it with gravel. No other anchoring method is
provided. Even though I'm located in the San Francisco Bay Area with not
that much wind but I'm concern about wind loading after installation. Has
anyone installed one of this?
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
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
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.
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.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.