billalla,

Thanks for your useful input and info. It appears I need to pay particular attention to build the base to minimize distortion of the greenhouse structure when there is extreme temperature fluctuation in late winter and early spring. This may not be easy to accomplish with minimal cost. I hope a reinforced frame of landscape tiles (pressure treated) on gravel base will be sufficient if I don't disturb the stable ground too much (no digging). I can't find much review info on the Palram. I think I will go with the Palram because it has 10 mm wall compare to the 6 mm of the Rion. The Palram roof angle is also better for snow load in winter.

You may want to consider a Riga. It has 10mm end walls and 8mm long walls. The onion shape sheds snow easily.

szut, Thank for your suggestion. I have already placed my order for the Palram. Also, I don't think I can easily source Riga in Canada.

I'm sure you are going to enjoy the Palram! Best of luck!

(Out of curiosity on the Palram - if the glazing needs to be replaced in the future do you have to take the greenhouse apart or can you just "pop out" the glazing for replacement? On the Riga I would have to take it all apart again!)

I just received the greenhouse today, and is in the process of installing it. I will let you know after I finish the installation. Judging by the installation procedure provided, it will, most likely, require removal of some structural elements to replace the glazing panels, but hopefully not too significant.

szut, I have just finished the installation of my Palram greenhouse. It appears that to replace any panel, it will be necessary to remove the eve first. Then the roof panel can be removed and replaced. To replace any wall panel, the adjacent roof panel needs to be removed first. The panel at both ends of the greenhouse will be more problematic to replace.

Thanks. For a Riga you have to remove the end of the greenhouse to replace any of the walls/roof (and all wall/roof panels between the broken one and the end wall). For the end walls you might be able to get away with removing a bit less, but still seems painful! I now worry about hale, or anything else that might hurt it! But on the other hand it should be pretty resilient to many mishaps.

I just purchased a Grandio Ascent 8x12. In the process of getting it put up. I chose this one because it seemed to have the best reviews as far as windy areas and it also has rain gutters, which is a big plus for me.

In my search, I did not come across Grandio greenhouse. It appears that they have very similar spec and prices compared with the equilvent Palram models. My Palram is very easy to install, but I am concerned that the 20' long model is a little too long for the size of its central roof structure (even though it is supposed to be certified in Europe). I will have to sweat through this winter to see whether it can hold up to the snow loads and severe wind storms. It also has rain gutters. Hope your Grandio greenhouse works out well for you. Just curious, why are the rain gutters important to you; for collecting rain water?

garcanad - How is your Palram Glory holding up so far? I'm considering purchasing the 12ft long version. I'm in southern Indiana, zone 6, so my winters won't be quite as cold as yours. I'm wanting to heat it some to grow tomatoes and peppers among other things almost year-round.

It is going through its first winter, and so far the winter has been mild. Also I am only using it as an unheated greenhouse to overwinter some plants. So, I can't offer much useful info for you. As far as wall material is concern, I think almost all brands use similar materials. I opted for a TwinWall thickness to maximize the heat insulation property. I put a piece to styrofoam to cover the Side Louver Window in winter. It would appear that the main heat loss would be between the wall panels and the structural frame, but I did not apply caulking there thinking that it may make panel replacement problematic in the future. In retrospect, my only regret so far is I should have gone for the Grandio for a 20 ft long greenhouse. I looked at the pictures of its structural design and it is a far more stronger design, but I don't know what is the quality of their structural components. However, for a 12 ft long (8'+4' ext), it is probably OK for the Palram. The Palram design is very clever for ease of installation with reasonably good precision components. Hope this help.

I am hoping you are still active in this thread and can tell me how you feel about your Palram, now, in early 2018. Has it held up well? Any problems over the last 3 years? Am considering a Glory, but I have pay someone to build it, so any info I have going into this project, will help. Thanks so much for posting an update, if you have one!

My Palram seems to hold up well so far. The problem I face is likely generic to all greenhouses of this type without heating. Moderating excessive temperature rise during the day and drop at night is difficult even with fan, shade cover and poly covered tents etc. inside. I must say that I only use it for over-wintering potted plants. Hope this help.

Yes, it does and I appreciate your input, so much! Thank you!. Having had another, wood, with plastic covered greenhouse, I have experience managing the temps. Fortunately, where I am, near Seattle, we don't have to fight the overheating as much as other areas. It is still a problem, and takes constant monitoring, but fans work for us here. Thanks again!

If you do some research, you will find out that both models made by Palram. Rion Grand is the best "Rion" Greenhouse, the same as Rion Prestige all 6mm polycarbonate twinwa sheets. Glory is the the best Palram brand greehouse due to the 10mm twin wall poly and metal framing Glory is the best hobby greenhouse in the market

I bought from greenhouses Canada and they are family own, you can actually talk to someone that know the products