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hothouse1

Polycarbonate panels failing

hothouse1
15 years ago

Harbor Freight polycarbonate panels aren't the only ones subject to failure. All the 6mm roof panels we on our roof have cracked open. They were installed when the greenhoue was built by a major greenhouse company in the spring of 2002 and are now in terrible shape. It seems the 10 year warranty will be honored this time but when they put the new panels on, they won't honor the new panels' warranty unless they install a 26 inch long curved piece of glass at the roof-side curve. It must be that the stress at the curve is causing failures on their panels. I don't know if this is where others have had failures but they are going to have to be replaced before winter. See photos at:

http://s310.photobucket.com/albums/kk436/ALU6/

Comments (9)

  • greenhouser
    15 years ago

    Wow! What a mess. The discoloring also looks horrible. I guess they're not made to bend like that.

    My HFGH is over 2 years old and still looks brand new. We cover it from late April until early October. We also cover the Rion.

  • laserfan
    15 years ago

    Were these panels "pre-curved" i.e. formed that way wherever they were manufactured? Or bent-over on-site? In any case it looks like stress accelerated their demise for sure.

    I wonder too if mfrs aren't experiencing more "premature failures" than expected given the higher levels of UV reaching Earth's surface these days.

    I would say to anyone using polycarb (plastic) that they absolutely need to cover those panels that take a direct hit of sunlight, especially during summer when the sun is highest. I figger ol' Sol is laughing at us thru the depleted ozone layer...

  • greenhouser
    15 years ago

    Both my Rion and HFGH are snugly covered and protected from the summer sun. The panels still look brand new on both - so far. :)

  • oakhill (zone 9A, Calif.)
    15 years ago

    Sorry about your polycarb panel problems. It may be that the design of the bend is more than is recommended. Just in looking at your photos and comparing to the recommendation, it looks like that may be at least part of the problem. The fact that the manufacturer now uses curved glass instead of trying to bend the polycarbonate too far supports this idea.

    Here is a link that might be useful: polycarb bending ratios

  • medontdo
    15 years ago

    that totally sucks!! i really wanted one of them types!! but they were so exzpensive!! i'm so glad they're gonna honor it for you!! that would be so heart breaking! ~Medo

  • hothouse1
    Original Author
    15 years ago

    The panels on the greenhouse were flat when the company people brought them in and they were gradually bent to the curve upon installation. The roof has always been covered by shade cloth, also supplied by the manufacturer.

  • babalubird
    15 years ago

    What a shame.

    I can't thank you enough though for sharing this info and photos. We were seriously thinking about this material for our greenhouse which would be curved and subject to severe winds and very hot sun. You just saved us from a ton of grief, no doubt.

    Connie

  • calliope
    15 years ago

    Yes, they'll fail with that much curvature on a straight piece of polycarb. One of my smaller g'houses is polycarb twin wall, and we actually had it designed for the spot and they sent one of their engineers down to look it over to make sure it would 'fly'. Well, I didn't have good feelings when they did a bend on mine down near the bottom. Was told it would be guaranteed. It failed within three years. We didn't even ask to have it replaced, as it would just do the same thing again. What we did was replace the lower two feet of the g'house (where they were putting the bend) with other building materials and then attached the glazing to that and just cut the cracked part off. No problems since. We are prolly on year ten or more now, and it's still clear and functional. The polycarb will bend safely over the slight arch of your typical quonset or gothic roof, but wow, bending it that much like in your pic is asking a lot.

  • calliope
    15 years ago

    The discoloration on the panels in the picture are where water has gotten between the walls of the panels and is algae. When we installed the twin wall, the instructions were to use a waterproofing tape over the open ends of the gaps before you slide them into the channels. Otherwise, even if water doesn't get in grossly, moisture will make for condensation and decrease the light transmission.