Hi steve333, good question. I always said I'd never buy HF panels again, but when I was faced with the purchase, I caved! It was a combination of price, and convenience. At the time, I priced 4mm twinwall polycarbonate at a number of greenhouse supply companies. The best price at the time was through FarmTek (cheaper than Charlie's or any other source I tried.) Their product had a ten year warranty, and was truly UV-protected. However, the cost to purchase enough material (just for the roof) with crating and shipping fees to my address, was $410. The cost to order more Harbor Freight roof panels, with shipping, was $135. That difference was enough to give me pause. Hmmmm. Note, it's possible folks living closer to urban areas with more businesses would have found better deals on shipping, but down here in southern NM, the only things close to us are lizards and cactus. Also, the HF panels arrive sized to fit; if you buy better polycarbonate from a greenhouse supply company, you'll have to cut the material to size yourself for each part. Not difficult, but it does take time, so I factored the convenience in as well. Also, occasionally I consider upgrading to a larger home-built greenhouse, so kicking the can down the road doesn't bother me as much as it would if I was positive I wanted to keep this small greenhouse another ten years. I think an argument could be made for both sides. If rtyu's and my experimentation with the Top Secrets clear epoxy product pans out, though, it will definitely tip the scales towards using the (clearly lower quality) HF panels and protecting them with the coating, especially if folks can apply it to their new greenhouses, and avoid the need for panel replacements. Fingers crossed. I think much of the appeal of the Harbor Freight greenhouses is cost/value. They appeal to folks who want to try greenhousing but don't want to make a major investment. I haven't tallied it up exactly for a while, but scrounging supplies, materials, and labor, I figure we have around $2500 in ours total, including kit, benches, sink, plumbing, electric, heaters, thermostats, shadecloth, pavers, and the new roof panels. Over six years that's roughly $400 a year (not including heating costs, which aren't too bad in my climate.) So I think many folks who are attracted to the HF structures also enjoy keeping costs low. It's just one option in the world of greenhouses, and not the right fit for everyone. Happy New Year!

Hello BearBryant (Roll Tide!) I haven't come across anyone yet with reports of how the Krylon spray product might work. I met one person who planned to use it over a year ago, but when I contacted him for an update, he said his build had been delayed. Since this thread, another HFGH owner posted to the thread linked below. Rtyu said he'd applied the Top Secret TS-100 coating mentoned above, three years ago, and was still very pleased to see no deterioration. You will find his posts close to the end of this thread: HFGH Polycarbonate Panels Failing, Part 2 Between the two products, I'd probably bank more on the Top Secret coating, because it's roller applied, and that will likely allow a thicker and more consistent protective coating than the Krylon spray product. Just a guess on my part, though.

rjinga, I took some pics for ya to help out. first this is from the outside looking up to the back left side(right form the outside lol) of the PC panals the bolt heads are hiden behind the tape tho but you can see everythingis sitting flush This pic is from the inside looking up to the back left corner. as long as you put your bolt and nut on the top holes of part #49 an the top hole of the corner post befor you add side wall diagnial part #80 everything will fit nice. By the way I added both parts 79 and 80 to my corner post and it really stiffened up the frame where I din't have to worie about the winds 10 - 20 mph for the next 2 days before I could get back to working on it Here is the camera up tight to the back panal looking up to the gutter and part #80 to the left. On the right side of the corner post you can see my weatherstriping and how there is no buldge. If I had turned that nut and bolt arround like you have in your 4th and 5th pics then it would be sticking out past the PC panal. I hope this helped. JBa3Fan ..... I'm Jim the other jbest123 is John lol .

We had to replace a few panels after taking a direct hit by Hurricane Sandy. Panels blew out and were strewn around our yard and neighbors' yards like huge snowflakes. Remarkably few were broken or even cracked. Anyway, my husband ordered panels online from Home Depot. They arrived fairly quickly, weren't too costly, and were easy to cut to size.