polycarbonate

whats the pros and cons over both single and double layer polycarbonate over glass other than its child/vandal safer

thanx

 

I think polycarbonate is more likely to blow out (in gale), let less light though, and become discoloured with age. It may be a better insulator in the Winter (particularly the double-skin types).

Greenhouse frames for polycarbonate will carry less weight, so are probably lighter-construction and cheaper? Dunno how well they cope with snow loading though?

 

I have a double walled polycarbonate greenhouse 1 year old and have no problems with light issues or heavy wind. i am very pleased with it. Not tried snow though, we must have been the only place that didn't get snow last winter lol

 

I built my own g/house and used poly. panels. Can't see a problem with snow. If you're offered cold weather, wouldn't you heat the g/house? That would stop the snow from settling.

 

The snow itself would be a much better insulator :wink:
The frame has to handle the load and as Kristen mentioned the fact that polycarb is lightweight means the manufacturers could reduce the strength of the frame to save money. Try to obtain a copy of the structural testing report for your greenhouse :wink:
Heres a typical structural spec for a greenhouse:
Snow/roof loads: 10 pounds per square foot uniform roof snow load on the horizontal projection. In addition roof members shall be designed for the 100 pound concentrated load (point loading).
This load need not be applied at more than one location at a time, but should be applied simultaneously with the snow and wind load.
If you can hang the equivalent of two 55lb bags of potatoes from a single point on your roof rafters you should be ok.. i doubt many would be brave enough to try it :wink:

 

"i doubt many would be brave enough to try it"

Rhino Greenhouses do - in their marketing material

" If you're offered cold weather, wouldn't you heat the g/house?"

Well, mine is a cold greenhouse, so not in my case!

"That would stop the snow from settling. "

Actually if it didn't melt the snow that would be better I think - it would show that the polycarbonate was insulating well :thumb:

 

Looks like the Rhino is upto scratch then :wink:

 

I have one of those plastic greenhouses ,which i am currently replacing some time by Christmas,
Anyway we live on a very windy spot and as we were going on holiday for 3 months last winter, we wanted to be sure the greenhouse was secure, really just so the neighbours couldn`t complain if it broke up,
So i filled 2 of those builders buckets you get in Focus with water, and suspended them from the roof bar with long Bunjees ?
I think they hold a couple of gallon and when we returned home all was safe and sound, I don`t know what the weight of it would be but it must be 30lbs or so

 

Because its one f those Poly-thene type and i am having a polycarb , we have the base ready ,just the will to erect the greenhouse is needed ,
I will say though i have fared very well with my polythene up to now, but the cover is held together with duck tape ,and the zips broken ,but its well ventilated :lollol:

 

If I may, I would like to tag a question onto this tread. Space is a premium in my garden and I have been thinking of one of those small (table top if you like) plastic greenhouses. The area available is sheltered and predominately shady. Am I wasting my time comptiplating such a purchase?

 

I have one of those ,again the zip is broken I have to close it with pegs
but they do give you a start if you dont have room for a grrenhouse , some of the members even bring them into the house/shed in winter, and you can start off a lot of your seeds,
Also you can then put them outside to harden off plants as they do offer some protection in Spring ,
For the £10/£15 they cost they do a job ,just be careful of the zips,

 

Thank you for that. I have read a lot about the zip problem. Seems it is a common fault.

 

"Seems it is a common fault"

It wasn't here ... until we went away and left my in-laws to look after my zipups :(