mudhouse - there was probably 10 inches of snow on the roof. I recognize that I should have gone out earlier and knocked it off but I'm a bit overwhelmed with life and business at the moment, and I simply didn't think about the risk of the weight on the roof. Actually, most of the snow we had received in the storm was very light and fluffy. The problem developed, I believe, after the storm broke and the snow began to accumulate moisture & weight as it started to melt. busy1 - I employed the same reinforcement of 3 lengths of EMD across the interior. That's nice for stiffening the walls but didn't make a difference in terms of this issue. ole_dawg - thanks for telling me about a guy on ebay. I'll have a look. If you happen to have the seller's name, I'd appreciate it. rosepedal - the 1x? material you have running from front to rear is sort of what I have in mind, but my thinking is that it needs to be centered between the ridge and the wall. Additionally, I would really want a minimum of one sturdy post, such as a 2x4, running vertically between those and the ground. This way there is some strength that prevents those boards themselves from bowing under the weight. As mudhouse mentions, the unsupported centers of the roof studs are the weak point. No question about it. Thanks for an occasional kick on this thread. It would be great if someone who has their remaining parts around might see this. I can be contacted directly at greg at greybearddesign dot com.

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!

As far as I know, you shouldn't have to caulk the roof panels in your HFGH to make the roof watertight. Someone may correct me, but I don't recall reading about anyone who had to caulk all the roof panels to correct a leak problem. I used foam weatherstripping on all four edges of my panels, roof and wall, as I installed them. I did it to get a good air seal to avoid heat loss during the winter, but I suppose the good seal provided by the weatherstripping might also help keep things water tight. The foam weatherstripping was a bit of a pain to apply, but it really does help with the seal, and I like it because I can still remove any panels if I want to, unlike panels that are caulked in place. I haven't had any roof leaks, and mine is going on three years old. However, I honestly don't recall reading about this as a problem among folks who didn't use weatherstripping, either. Is it leaking at the four corners, where the roof touches the corner wall posts? I had some big gaps (and leaks) at the top of all four corner posts, after everything was assembled. I fixed that with little folded over pieces of weatherstripping, covered with aluminum tape, and sealed over with clear silicone caulk. It wasn't very elegant, but the gaps were fairly large, and that solved the problem. No more water running down the corner posts during a rain. I also caulked my roof window panels into the roof window frames, but not because of leaks; it was because the poly panels for my windows were a bit too small to fit snugly in the frames, and they tended to shift around in the window frames in high winds. Those are the only panels I've used caulk on, in my greenhouse. I'm hoping someone else will chime in here, since this isn't a problem I've experienced on my own HF 10x12. Did you order extra clips to install the panels, or did you only use the clips supplied with the kit? I'm just trying to think of anything that might help improve contact between the roof panels and the frame. My roof panels are secured with extra clips (and a screw into the frame, for protection against wind loss.)

east20, I hesitated to jump on your post in case others had some good ideas for you. We did use a barrier between the HFGH steel base and our pressure treated lumber, but only out of an abundance of caution, after reading here that others did so. I will say after four years our HFGH base still looks like new, so we are pleased with how the (powder coated?) finish has held up. Also, I try to check various garden forums online for HFGH issues, and haven't seen any posts regarding the problem of corrosion between the base and pressure treated lumber. I get a pretty good number of comments and questions posted to my blog about building our HFGH, and so far nobody has posted a comment about any steel base/treated lumber/ corrosion issues either, so I'm hoping you won't have any troubles. I'm guessing that corrosive processes happen faster when moisture is introduced. Our base sits high on our wood, above the soil level, in a dry climate. If your base sits at or below ground level, in a wet climate, your mileage may vary, but based on things I've read, my two cents is not to lose much sleep over it. Maybe someone else will pop in here with a preventative idea for you, but I'd tend to I'd just keep an eye out for problems, while you enjoy your greenhouse. Building our HFGH