MissAgnes, I doubt that you will be able to locate specific statistics for snow or wind load for the HFGH (and I am very doubtful that Harbor Freight has this info, or will attempt to estimate it for you.) To be honest, their focus is not on long-term durability; it's on selling as many inexpensive kits as they can. The rest is up to us, as HFGH owners. I honestly have no idea how this might be calculated for the modified greenhouse; I can tell you that we estimate our modified greenhouse has handled wind gusts over 50mph on numerous occasions, and possibly a few 60mph gusts in the last six years, with no damage. However, our greenhouse is sheltered on the north side by our house, and we don't have any monitoring equipment, so this certainly isn't any kind of scientific evaluation. My guess is the wind resistance of the Harbor Freight greenhouse, built out of the kit, with no modifications, is ridiculously low (laughable.) In my opinion, it's almost certain to fail; it's just a matter of how much time before the event happens. There are many old posts here with sad tales of those who have watched their (unmodified) structure being permanently destroyed by wind. Also, many sad reviews on the Harbor Freight website, from folks who didn't know how critical the modifications were. Same story with snow load; I have no idea who would have exact figures, but I can tell you there are posts archived here of roof failures from snow. The weakest portion seems to be the center of the roof studs, so that's the area most folks focus on, when trying to build for snow load. I have gathered some links to older threads here regarding snow modifications, and they are posted in the Comments section of Part One of my blog (scroll down about 2/3 of the way through the comments at the page below, and look for the question posted by snwplwdrvr.) Part One, Building our 10x12 Harbor Freight Greenhouse Hope this helps!

It looks as though your panic attack has subsided. Good. I have had the 6x8 for some years now (I think four?) and still enjoy it. Would love to move up to the 8x10 but not sure if there's room for it. So, lucky you! I'm 5'7" and placed mine on a foundation of 2x10's for a little extra height; there is room to work without stooping and I don't mind having to step over the threshhold. My greenhouse is in a somewhat protected spot, with a large white oak to the west, a fence and naturalized area to the north and garden shed to the east, but I've not had any problems with wind. It is neither tied down, with minimal anchoring at the corners. We did, however, run two protective layers around the perimeter inside - under the gravel and up along the foundation: first a layer of hardware cloth to exclude burrowing animals that may wish to overwinter there, and then a layer of Reflectix insulation to exclude drafts. A couple of years ago I swept the gravel off to the sides and set a gray paver walkway down the middle (I'm an incorrigible barefoot gardener). There are several options for shelves. Someone posted photos of shelves secured to center posts at each end. Very nice. Mine are white cedar on the cheap: a local manufacturer/retailer/installer of fencing materials sells their picket fencing seconds for $10/3'x8' section. Cut off the pickets ends outside the two horizontal rails, and we had a bench top just the right size. Our winters are probably a little warmer here in coastal NJ than your RI winters, but I use the GH all winter. We put on its winter coat, a clear solar pool cover, in early November, and the 1" foam insulation panel on the north wall stays up year 'round. The insulation panels on the north 1/3 of the east and west walls, like the strip of Reflectix insulation on the lower part of the north roof, come down in spring. I overwinter tender perennials, grow some veggies and herbs through the winter, rotate house plants through for R&R, have a few orchids, start forced bulbs, start other rhizomes/bulbs/tubers for spring planting outside, and grow some seedlings - most are wintersown, but the tomatoes have to be started inside because I just can't wait for that first fresh, home-grown Jersey tomato! My husband enjoys the greenhouse, too ... no, he's not a gardener, he just likes to sit out there and read, lol. Not a bad idea to leave room for a chair while you're planning your space. That greenhouse will be arriving soon ... good luck and enjoy! (And please keep us posted.)

Gardiner is the HFGH construction expert here, but I would like to suggest an alternative to a sheet of plastic between your aluminum base and copper treated timbers. Check your local big box home center for the rolls of 3- 1/2" wide vinyl sold for sealing sills under standard 2 x 4 framed exterior walls and unlike plastic sheeting, made to last as long as the structure. Every time we visit our local Menard's and/or Home Depot or Lowe's, I'm always amazed at the latest in materials and just as regretful that they weren't around when our old house was constructed, so do wander the construction materials areas, and you too may find a product that may not be advertised exactly for your intended use, but one that could prove ideal anyway. Another possibility is vinyl siding. It comes in 10 ft. lengths, is very cheap per piece, but again, made to withstand the elements and just a few pieces of the 5" width laps, would cut to fit and cover the tops of the timbers. Of course, the ultimate and perhaps, in the end, best of all timbers for a GH base, might be the resin timbers that will never rot, are always perfectly straight, will never bow or warp, and don't require any barrier at all.

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!