Hello I too have had my HFGH sitting in the garage for 2 years and was getting ready to tackle this over the Memorial Day weekend and found the same problem. The ends of the base have blistered and rust is now on the ends of the base pieces. Im sure sanding them a little and maybe using some Rustoleum paint will fix them. What does anyone else think?

svalli and kicksnj, I apologize to both of you for missing your posts. I haven't been able to check here for a while.

My husband and I made our living by forging iron and fabricating items out of mild steel, so I'm pretty familiar with my old friend rust (we have a saying, rust never sleeps.) Steel is always trying to return to its natural oxidized state, but with modern finishes and a little maintenance, we can usually keep the enemy at bay (in most climates, anyway!) Sorry to hear that rust is trying to interrupt your greenhouse projects.

Without seeing photos of the rusted bases, I'd tend to imagine the blistered paint and underlying rust are more of an annoying (and admittedly worrisome-looking) cosmetic issue than a true structural risk. My approach would be what kicksnj suggested; remove any loose or blistering paint with a steel bristle brush, rough sand paper, or rough abrasive pad. Then prime any roughed-up areas with a good metal spray primer (Rustoleum is good) and follow with another coat or two of a good spray paint made for exterior use (again, Rustoleum is a decent brand.) I'd sure rather pursue this approach than to abandon using the base, since as svalli mentioned, the clips that hold the vertical aluminum beams in place are anchored by the formed lip on the steel base, and then you have another set of challenges.

I wonder if Harbor Freight has modified the finish on these steel bases, as our 4-year old base still doesn't show any signs of rust (but, we do live in a dry climate.)

Svalli, since you've already constructed the two-by-four replacement base, I'm trying to visualize your challenge. I'm sure you've found that the hold-down connectors (part 47) do two things at the same time; they not only secure the aluminum floor plates (parts 1 - 6) to the steel base; they also attach the vertical aluminum wall studs, at the same time. So, even after you screw the aluminum floor plates to the top of your two-by-fours, you'll have to figure out how to attach the vertical wall studs to the aluminum floor plates, with no hold-down connectors to help. You may already have a solution for that, but I'm just making sure.

The polycarbonate panels do touch the vertical lip of the aluminum floor plate; the panel clips (part 53) press the panels tightly against the aluminum frame, from the outside of the greenhouse, for air-tightness. It would probably be best if the screw heads did not fall in the area closest to the vertical lip, since it might affect the panel fit.

The actual measurement from the outside of the poly panel to the outside of the aluminum floor plate can vary, depending on whether or not you use weather stripping between the polycarbonate panel and the aluminum frame. (I did.) What matters most is that you realize the poly panel needs to be able to fit tightly to the frame (or to the weatherstripping smooshed against the frame) if you want to avoid air leaks.

If I'm misunderstanding, please feel free to post back! Again, apologies for my slow reply. I hope some of this helps. Hang in there, the challenge has been well worth the end results for me.

Thanks for your reply mudhouse,

We finished building the greenhouse last night. We screwed down the floor plates to the 2x4"s close to the outer edge, which gave enough room for the panels. The vertical beams are screwed to the holes on the floor plate lip, where the hold down connectors, would have gone also. I think that this should be sufficient way of attaching them.

I live in area with rainy falls and snowy winters, so having rusting metal close to the ground does not sound like a good thing. The treated wood base worked fine, since we made it the same outer diameter as the steel one and made it exactly level and rectangular.

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Svalli, that looks great, and congratulations on completing the structure! One of the good things about this kit is it seems to lend itself to innovation for those who are willing to do the extra work (and problem-solving) to arrive at the best solution for their needs, and their climate.

If it's helpful, there are occasional threads in this forum about adding bracing to the center of the roof studs, to support them during snowfall. Some folks here have managed to do so using different methods.

Also, some folks in freezing/snowy climates have found the sliding doors to be a challenge, because the track can collect ice. (This has only happened once to me in four years, during a record freeze in February, but it did shut me out of the greenhouse for about 18 hours.) Some have replaced the sliding doors with hinged doors. If you need help finding any of these threads, feel free to contact me and I'll try to help.

You have a very beautiful setting for your greenhouse.

Thanks mudhouse!
Since it gets really cold here, we will not be using the greenhouse during winter. Additional support in the center during winter may be needed, if we get as much snow as last winter. I will try to remove the snow before it accumulates, but overnight storms may cause problems for an unsupported strucure. We put in 5 horizontal braces made of aluminum pipe with similar brackets like in your blog. Before we installed them, the crown was concaved and sides pulling apart, so those are really essential for strengthening this greenhouse.

I agree, cross braces of some type are very important with this GH, and I am very grateful to the first builders of the (then new) 10x12 who started posting those critical tips here. If I hadn't read countless helpful posts here about how to beef up the structure, I don't think we would have had the courage to tackle it, being total newbies to greenhouses.

If it helps, I think this may have been the most recent thread discussing snow load brace ideas. I thought Polcat's solution was downright elegant.
HFGH snow brace idea thread

Best of luck to you, hopefully you can start getting on to the truly fun part now!