Gardnergal I just tried a different approach to my 10X12 foundation and it may also work for you: I placed Qty 4 green-treated 4x4 timbers INSIDE the greenhouse floor, criss-crossing them. I cut a slot on the bottom of each timber 1 1/16" from the end about 1/2" deep, such that the timber rests on top of the metal and holds it down. Then I put 4 lag bolts into every timber end (thru the foundation of course). Makes everything nice & straight & square, and the weight of the timbers oughta hold it down good. Then we filled it with pea gravel. Others will fret that the metal foundation contacting both ground and green-treated lumber is problematic; I don't think the things going to rust-out and/or fall down in my remaining lifetime. I will post pictures when I get a chance...

I bought one years ago so i can't help you with brand or current cost. But I bought enough in bulk to cover the top and front(south facing). I cut it into manageble pieces for 1 person. Sewed on edge fabric(to protect all edges) and installed my own brass grommets. I used a simple pulley system outside the GH for the roof area. I used j-hooks for the side(spaced approx 2ft apart). Mine are black,but the shading percent will depend on whats in the GH during the summer. sorry if this isn't much help. I start my new HFGH project tomorrow(foundation plan an layout).

Vicki, tell your hubby not to be such a nitpicker. The guy who levels the area can go a little bit over sized, and then it can be taken care of when you back fill to the size of the foundation. As far as the need for a true foundation, it looks like to me that this GH does not really require it. My recommendation is, unless you want to put it onto a poured concrete or laid concrete block foundation (which might require you to have a building permit) just dig holes at the corners, and about every two to three feet along the sides (on the inside) and set treated wood posts at least three feet deep. Then attach your treated two by eight base frame to it. I don't have one of these GH's yet, but hopefully someone who does will send you the dimensions from thiers. If not, open the box and find the instruction sheet. (If worse comes to worse, you may have to measure your base plates. I've bought Harbor Freight stuff in the past, and know first hand how "good" thier instructions are.) Kevin

Good morning Jeymac, Iâve been happy with the solution of putting wood framing along the inside of the base channel. I do think it strengthens it somewhat (prevents the c-shaped channel from flexing as easily.) Also after years of living with the greenhouse, I think the bottom of that channel would have been a great catch place for bits of gravel, plant leaves, dust, bugs, and other greenhouse debris. Having the wood there makes it look cleaner, and it really does stay a bit cleaner too. Iâm sure my wood does not look as pristine as it did, years ago, after I slobbered water all over the benches, week in and week out. But I never notice it, back there under the benches. Neither my husband or I can recall what Gardenerwantabeâs base braces looked like, although I bet at the time we looked at those photos and considered that. We must have decided they were not critical, along with the wood we used, as we are both drawing a blank on what his braces were. I guess we are getting old? I donât really have any knowledge of anyone else using braces on their base to strengthen it, so I donât think itâs a deal breaker, but I do understand the wisdom of thinking through any options for adding strength as you go. I donât have a great source of larger photos for the details of joining two greenhouses together, although I try to watch for that on the web, since the question of joining two greenhouses comes up fairly often. There have been a few folks who have mentioned doing this on GardenWeb, but I donât think any have posted step by step close up shots. Funnylady has been super nice when we have emailed, and I hope she can give you more specific answers. If you folks do join two together, you might consider doing a thread on Gardenweb with the nitty gritty details of how you joined them....Iâll bet others would thank you, down the road! So many times, I find that everybody who builds one of these seems to find their own way for resolving some of these questions. I know we did, too; we researched everything we could ahead of time, but often ended up finding our own solution, based what seemed practical at that moment...what we could find in the garage to use...and/or what we could find in the aisles of Lowes. In other words, on most any of these modifications, youâll find there is more than one way to skin the cat...and the way you find may well be a better solution than what other folks have done. I didnât make any notes about the length of the bolts we used with the EMT, but since the EMT is ¾â, weâre guessing maybe 1 ¼â bolts. Just enough to slip through the drilled EMT and add a washer and nut. Best of luck with your build!