Good point about the warranties! Hmmm, my GH roof is almost always covered with an endless supply of desert dust. I can hose it off, but it will be covered again in no time (in spring, anyway.) I have had a lurking concern that IF there is a panel deterioration problem, it may be heat related. I read a post on another forum last year from a Tucson GH owner who'd purchased two 6x8 kits to use the poly panels in his own homebuilt wood-framed GH. He posted that after a few years the roof panels were brittle and breaking. I know he doesn't use his GH in the summer at all, and I figured his roof panels must have been subjected to extreme temps (if it's 110° outside, imagine what it may be inside an uncooled GH in Tucson, especially the air right under the roof panels...140°? 150°?) I hoped my plan to use the GH year round might help me to escape the same fate (I'm hoping I can keep the temps in mine under 100°, although most of my plants will tolerate that.) Still, I note that the three mentions of this problem so far (the Tucson person, yours, and Jamesy40's) have all happened in southern states. If heat is a problem, mine will likely fail sooner than some...so I'm keeping an eye on this trend! I guess it could be an opportunity to upgrade the roof to 6mm at least, eh? :-) Sheri

In his blog about building his new 6x8 HFGH, dewey1945 shows how he applied 6 mil UV resistant plastic to the outside of his panels. I havenâÂÂt seen this idea discussed anywhere before, so IâÂÂm interested in following his blog: Apply the UV Resistant Skin When I replaced my roof panels in October of 2011, I applied a clear marine coating product to the outside of my new panels, before installing them. I also applied the same product to half of a scrap of HF polycarbonate (left over from installing my exhaust fan.) IâÂÂve left it exposed to the sun since October 2011. So far the treated side still looks shiny and clear, while the untreated side has started to look a bit dull and cloudy. Might be a good sign, but I think itâÂÂs still too early to tell if this product really does help. My cost to purchase a gallon of the product was around $100. The company (Top Secret Coatings) seems to have changed their product line since my purchase, so IâÂÂve emailed them to ask which product is the current equivalent of what I used. IâÂÂll post back here as with that info as soon as they reply. ItâÂÂs too bad we have to wait at least a few years to see if ideas like this truly will help extend the life of the HFGH polycarbonate panels. From my reading, folks in southern states with intense sun seem to report more panel failure. The topic hasnâÂÂt come up here at GardenWeb for a while, so IâÂÂm hoping that means folks in other climates arenâÂÂt having nearly as much of a problem. If you donâÂÂt do anything to protect your panels, and notice some problems in years to come, you can order replacement panels from Harbor Freight. The HF panels wonâÂÂt last as long as higher quality twinwall polycarbonate from other supply companies, (with real UV protection,) but they do cost a lot less. FYI, hereâÂÂs a summary of my pricing research from October 2011, for just enough material to replace the roof on my 10x12 HFGH, including shipping to my state: Farmtek 4mm twinwall polycarbonate, approx 10 yr warranty, about $410 Solexx 3.5 mm, (a flexible translucent white greenhouse covering material) about $350 Harbor Freight 4mm panels, $135 IâÂÂll be sure to post back with the Top Secret clear coating product number, so itâÂÂs recorded here for the thread.

Joe, in case you didn't see it, Laserfan posted this information recently about a 4mm polycarbonate product now available from Tek Supply: "I notice today that teksupply is carrying 4mm in the (much higher quality with UV protection) PALRAM polycarb. Expensive as all get-out, but here you go. If you look at this page, be sure to download both of the pdf files there as they contain excellent information about both the product and it's application/handling/installation etc. that you will find valuable I'm sure. Link to Teksuppy 4mm page: laserfan" If we eventually do have to replace our panels, I'll at least give a more expensive option like this some careful thought, since I figure it will be a major ordeal to replace the panels in mine (I'll have to empty out the greenhouse, which remains stuffed year round.) I don't want to spend big bucks...but I'd rather not replace the panels very often, either, and I now know the HF panels may well have a limited life span in my climate. Sheri

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.