Dear Sherry;
I'm in the process of building a homemade greenhouse against the side of a new barn, but here's the problem.
The county wants to see 80-100# of dead snowload capacity on the glass and the local glassman said thesliding door Themopane type glass won't hold up the load so.. now I'm looking for some new materials or some publishied test results to get the engineers so that I can get this thing approved.If you could point me to the right manufacturers for glass or plastic panels I would appreciate it.
Thank you,
Roger R.
Hello, Roger! Thank you for visiting my website. Sorry for the late answer. I've been on holiday, changing to a new computer and software (and having numerous difficulties too boring to describe), and preparing to remodel the house so extensively that we must move out completely. Of course, I continue to get the same volume of email. I enjoy reading and answering it, but sometimes it's difficult to catch up. So, it's been a little intense here lately.
I am not an authority on snow load, as I live in the coastal northwestern US.
I did find a very informative book while on holiday that you might find useful. It is entitled "Winter Greens - Solar Greenhouses for Cold Climates" by Editor Mark A. Craft, publisher Firefly Books Ltd, 3520 Pharmacy Ave, Unit 1-C, Scarborough, Ontario, Canada M1W 2T8.
The book addresses the snow load issue beginning on page 88, not from the standpoint of the type of glazing, but from the standpoint of how far apart to place the rafters to support the glazing for the load.
For example, as indicated in the table given, a 2x4 rafter could span up to 4' 8" and support a 100 lb/ft snowload. To support a 20 lb/ft snowload, the 2x4 rafter could span up to 8' 10", according to the table. This does not take into account the weight of the roof itself.
The book states that the maximum ground snow load data is available from your local building inspector. The book recommends designing your structure "for 60 percent of the heaviest ground snow load in your region, unless the roof is sheltered by an adjoining wall or roof. Sheltered Roofs should be designed for about twice the ground snow load because snow drifts will collect on them." They also say, "Do not design a roof for less than 20 lbs/sq ft snow load, no matter what."
Below are a few websites you might take a look at:
AG Answers - Ohio State Home Page, Purdue Home Page:
"Don't Trust 'Lean-To' Buildings During Heavy Snow"
"Heavy Snowfall Brings Concern About Farm Building Safety"
SnowSim - Simulation of Wind and Snow Loads
(computer model for simulation of wind and snow loads on buildings and structures)
This is for Norway, but snow is snow anywhere.Might not be directly useful to you, but an interesting site. Check the links on the sites.
by US Army Corps of Engineers (requires downloading a file)
Snow Loads and Heat Cables on Glazed Roofs
by Nielsen Anker, Narvik Institute of Technology, Narvik, Norway