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

I'm using Charlies clips and 1/4" diameter Fastenall aluminum bolts on mine. The clips from Charlies are significantly stiffer than those that come with the GH. The Fastenall bolts fit the channels in the wall and roof studs just fine. I was going to reinforce the corner wall studs as described by gardenerwantabe but found that once the roof studs were on the GH frame was solid. An experiment with a Univent automatic vent opener has convinced me these will be fine for this GH. I'll be ordering one for each vent. Hope this is helpful, SH

johnnyq, I'm not much help, since I've been shamelessly kicking the can down the road for years now. Made it through the last two winters with a layer of 6 mil greenhouse plastic sheeting over my own badly damaged polycarbonate roof. We've replaced the roof panels once already, and I only get about three years in the HFGH panels before small holes start showing up in the outside layer of the roof poly panels (even with shadecloth in place all year.) I'm lucky we didn't have a wet heavy snow this winter, or we would have been out there rigging up emergency interior bracing! All of my wall panels are still original, and are now about ten years old. They've finally yellowed and developed small holes too, so I'm looking at a sizeable investment to replace all the roof and wall panels. To be honest I'm doing some soul searching about keeping the greenhouse, but I probably will go ahead with the replacement, since all is fine except for the panels. And I'm not sure I want to give up the hobby quite yet. My plan is to buy 4mm twinwall poly elsewhere (not Harbor Freight, as I'm just getting too old to deal with the work of replacing the roof so often.) Last time I checked, FarmTek seemed to be my best source price wise. Did you mean that HF is offering 6mm panels with a warranty now? One (potential?) heads up is there might be a slight glitch with getting 6mm thick panels to slip into the aluminum framing at the roof peak - as you know the panels slide into a channel up there - and there has been past discussion that anything thicker than 4mm might not slide into the channel easily. I don't know if this is a problem with the kits that are newer than mine, though, and it might not be an insurmountable problem. Maybe others will chime in with panel replacement updates.

Hi oldlady59, our 10x12 has been up 8 years now, in a windy climate, using the screws and extra clips method. I didn't want to use caulk to secure the panels, because I like the flexibility of being able to remove them (the south wall of mine is replaced by screens in the summer time.) But I've heard good reports about using the caulk method, too. I don't know how hard it is to remove caulked panels, years later. People seem to report different experiences with the panels; my only guess is, it's based on climate and how severe the sun exposure is. Maybe there's even some variability in the manufacturing of the panels? I dunno. We had to replace our roof panels after a bit over three years. They were under Aluminet shade cloth, but our very intense sun in southern NM took a toll, and they were yellowed and full of small holes in the outer layer. Most of my side wall panels are now in the same state, but it took those almost 8 years. The panels on the north side of my greenhouse (sheltered by our house and interior insulation) still look like new. At the end of this thread, there's a discussion about a clear product that may be helpful in extending the life of the HF poly panels. I've used it and so has another GardenWeb member. So far it does seem to help, although I can't say for how long (time will tell I guess.) Harbor Freight Greenhouse polycarbonate panels failing When I order new side panels, I'll be using this product on them before installation.