Thanks SoTX! We actually have a bunch of white quartz landscaping rock in a big pile on the other side of the shop, so that is what I'll use. It was an eyesore in the front flower beds, but will work well for greenhouse flooring. I hadn't thought about the heat sink aspect, but that would be good motivation for digging the floor out by a couple inches and adding more rock (plus, that pile will shrink more and get out of my way). Sunnibel, great idea using the clear roofing for your chooks. My coop gets too much shade in the summer as it is, my girls probably would have appreciated a clear roof (plus they can stargaze at night). Good luck working on hubby for the GH. My dad and I just started building while my DH was at work. Ask for forgiveness instead of permission, that's my motto!

Yes, it's my understanding that most if not all panels are only treated on one side (I'm told there's no reason to add the expensive coating to the inside) and they're marked so folks can be sure to install the UV coated side out. However, the HF poly panels have no marking on either side. When folks call to ask which side needs to face out, the traditional answer from HF seems to be "it doesn't matter." Last May I emailed HF with pointed questions about the existence of a UV coating on their panels, and their vague answer seemed to admit neither side is coated. These threads may help: HFGH Polycarb Panels Failing! HFGH Polycarbonate Panels Failing (Part 2) I do note, the level of problem seems to be greatly affected by location and climate. I know of at least one other GW member with a HFGH in Missouri who does not note deterioration problems after several years; also, those who use shadecloth on the exterior surfaces seem to fare better. It's just something to consider as you weigh out the pros and cons (and it helps explain why the HFGH kits cost so much less than all the others.) In the above threads I mention a clear coating from Top Secret Products I was going to try, but due to a badly timed illness and house renovation I didn't apply it to my panels, so I muffed my chance to see if it would help. My own HF panels are now noticeably yellowed and more brittle after a few years in the NM sun, so my greenhouse is no longer a good test subject. So far I haven't seen anyone post here with other solutions about coatings to apply. I sure understand about imaginary budgets! The low price of the HFGH kit (and all the good info here in this forum) gave me the courage to take the plunge into our first greenhouse. If you didn't have to change the roof pitch I'd be more optimistic it would be worth the work, and maybe worth the risk of shorter panel life. I ran this question by my husband also, and he also says he doesn't think you could use the top wall rail as included in the kit, since the angle would be wrong for your greenhouse roof pitch.

Hey everyone been out of the circle for a while. The polycarbonate i use is from home cheapo, I use 46% shadecloth over the gabel roof. on the lower roof I don't have any cloth. That is my test area to see how much light I can get away with. This time of year the sun is so far south it gets mostly sun through the side. Just a roof cover should be fine. I have a 20 inch exhaust fan inside the greenhouse with a thermostat set at 85 degrees.

It's been a awhile since I have worked with vinyl siding, but I would be concerned with the max temps your GH will reach in the summer warping the siding. Even if you ventilate it will likely hit upper 90's to 100F air temps, and depending on the color of the siding it could get quite a bit hotter on the siding itself. It might be safest to remove the vinyl siding from inside the GH when you add the attachment struct for the GH. Also textured vinyl lap siding tends to have lots of grooves, hollows, and spots to collect mold, etc, so you might want a better surface in there regardless of the heat issue, and a white one to reflect maximum light back to the plants. I would think that if you are putting a long 2x4 (or whatever) up along the upper attachment point with connections into each stud along its length, that would be adequate. Of course it will depend upon the snow and wind loads you get. You could check with a builder or civil engineer. If you could put a room on the size of your GH and the wall would hold, then it should be fine with the GH. Although you will likely need to use similar attachments for the GH as one would use for a room extension (remove siding under the attachment members, nail/screw into existing garage framing, adding it inside if needed). One concern may be frost heaving. If your gh "foundation" will be nothing more than some timbers laying on the ground, then it is likely that it will move as the ground freezes and thaws over the winter. That will cause added stress to GH where it attaches to the not moving garage. Something to consider. As far as insulation goes, if you don't insulate the garage wall to the GH, then you will loose/gain more heat thru it. If you were planning on using the garage as a heat sink that might be OK (although you'd probably need the rest of the garage insulated to hold that heat). But in general it is probably easier to insulate the GH-garage wall and put in fans/vents if you decide to use the garage as a heat sink/store. If you know how cold the garage gets at night and what the GH temp and outside temp is, you can do a quick calculation of the heat losses thru each surface. That would give you guideline as to whether insulating that wall would be worth it or not. Depending upon the numbers, you might find that insulation there gets you some additional above freezing time at each end of the season.