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!

The amount of heat depends on how well you insulate and seal it. If you try to heat it just like it comes then the above post would be about right but last month I kept mine at 65F when it was 12 below with wind chill of -50 and I did it with two 1500 watt heaters and a third one that was set on 750 watts. I set the one for 750 to run continuous and the other two were controlled by a thermostat. Most of the time the two heaters are plenty.

I posted new photos of the greenhouse (3rd box and floor are now complete) http://www.gbdg.net/g2/main.php?g2_itemId=93 as well as the completed garden http://www.gbdg.net/g2/main.php?g2_itemId=16&g2_page=3 There are photos of another HFGH that features fans. I'm quite certain you can rig a fan up there so long as the extention does not conflict with any bracing you installed (such as the 1/2" rigid conduit that I and others used to brace the walls.) The timbers that form the footing of the GH are 2x12 pressure treated fir. I did that a year ago when I started this project, but today I would have used the same rough cedar which I discovered later that summer at a local mill. I used the same PT fir for the outside steps and cedar for the interior steps. The steps make access to the GH a lot more convenient and being in snow country it allowed the base of the GH to be largely above the level of the typical snowfall here. This is our first season growing in the GH but it's mid-July and we just recently pulled out the lettuce and spinach that had gone to seed. A new lettuce crop (seeds)is in the newly built 3rd box - time will tell how that goes. It gets awfully hot in there though. As for weight, someone else might answer that. I strapped the various shelves to the sides and have seen no problem from the weight of the starting trays. However, I plan to replace the shelves (right now we are using the wire closet organizer shelves) with the style that Cactusfreak features in his HFGH photos. I want the additional space they will provide as well as to have them supported by pipes mounted above the raised bed boxes.

I would not put that thin piece of sheet metal in the wet ground it will be destroyed in a few years. Ignore the instructions and put it on 4X4 treated timbers anchor the base to the timbers with stainless steel bolts or the treated timbers will eat your bolts. Also lay something between the base and the timbers. I used a strip that I cut from a old poly tarp Do a search for 10x12 HFGH everything has been discussed here before.If you live where their is a lot of wind you must do the modifications that I outlined in previous post or you will lose it to the first storm.