Tag Archives: wind forces and structures

Greenhouses 101 & 202

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Norm spoke at the Guelph Organic Conference January 31, 2015 on Greenhouses 101: Knowing the basics before you buy-Choices and Consquences
You can find the articles and information posted, as well as a video of his presentation and the Q&A below.

Greenhouses 101: What are you trying to accomplish? What are you dealing with?Greenhouses 101: Climate and Air Effects on your Structure
Greenhosues: 101: Covering Options
Greenhouses 101: Greenhouse Shapes & Configurations
Greenhouses 101: Orientation and Location
Greenhouses 101: Knowing the basics before you buy Greenhouses 101: Greenhouse Choices

Norm did a presentation at the Guelph Organic Conference on Greenhouses 202: Making sure your structure survives the elements. The presentation is broken into three parts for easy viewing, the last section of which is the Q&A. These tips apply for greenhouses, storage buildings, livestock shelters, really anything we sell. Key Points Covered in the presentation:

  1. Some basic principles of engineering so that the forces exerted on the buildings could be better understood.
  2. The many components of anchoring. Anchoring prevents a structure from settling under snow load, prevents lifting under aerodynamic forces and prevents shifting with wind forces.
  3. The similarities of an airplane wing to the shape of a structure. What happens when surfaces become bigger, wider. lower and higher.
  4. How uneven loads can happen and how to prevent them.
  5. The proper procedure to removing excessive snow load

Read more here: Greenhouses 202: How to get your structure to survive the elements

Watch more here:

How to Manage Structures in Extremely Windy Locations

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Click to watch the video

How to Manage Structures in Extremely Windy Locations

One of the things which frequently comes up in the conversation with new customers is that they are in a very windy location. This is important to take into consideration when making suggestions for a building.

Occasionally we are faced with an intensely windy location. The question becomes, “Can I build a greenhouse in such a spot?” The short answer is “yes”. There are five potential suggestions which we make to improve the building so it is better able to withstand regularly brutal winds.

-Go with a lower profile shape since it catches less wind. Normally we recommend high profile since it sheds snow better but in super windy locations, snow is not an issue.

-Go with narrower hoop spacing. Going from 4’ to 3’ spacing increases the strength by 33%. Sometimes it is even worth going to 2’ spacing.

-Put in more anchors. There simply is no such thing as too many anchors! In super windy locations it is worth doubling up on the anchors. It is also important to double up on the fastener between the base beam and the anchor.

-Install cross ties. Cross ties tie the left and right sides of the building together. This means that when there is added pressure on one side, the other side is assisting by holding things back.

-Go with a double plastic cover with air between. It is amazing how the cushion of air acts like a shock absorber and stiffens the building.

Depending on the severity of your situation, adding a few of these to your building may help achieve the peace of mind you are looking for. We have had situations where a customer has added all five suggestions and been extremely grateful for the rigidity which has been gained.

As much as you, we want this building to serve your needs for many years with peace of mind.

You’re in a Windy Area? We can help

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We have many structures in very windy locations from coast to coast. This is probably the most common comment we get from people who reach out to us. We have experience and extra steps we take to help ensure your structure doesn’t end up as an expensive kite. We have been diligent in our articles and instruction manual to help these situations, but ultimately it’s up to the customer to heed these warnings.

One of the things that is stressed in our assembly instructions is the importance of tying your frame off in both directions as soon as you have the first section of ridge installed. This is typically done with rope coming down from the ridge as an inverted “V”. The sooner this is done, the easier it is to hold everything plumb.

It is worth noting / stressing, that this is not a long term replacement for the wind braces. The wind on the collective surface of all the hoops is capable of exerting a tremendous amount of force.

When one does the math, there are actually cases where the wind pushes with more force when there is no cover on the building then with a cover!

A 20’ x 48’ x 12’ high structure with 4’ spacing has the same amount of hoop surface as an 8’ x 14’ wall. This is an example why the ropes used to hold the frame straight is not intended as a wind brace.

Once the hoops are all installed and the purlins attached, it is important to install the wind braces before proceeding. The purlins are what tie all of the hoops together and then by angling the wind braces down from the rows of purlins, you would be bracing the whole structure.

In photos on our website,you will see our smaller structures have fewer wind braces than the larger ones, which accounts for the above math mentioned. This has been developed with our experience, as well as the engineers who have assessed our structures.

There are different notes on placement, direction and location that will help your structure survive the wind as well. We do our best to go over all the scenarios with you when you’re discussing your purchase with us. The more details you can give us the better. Obviously we aren’t able to account for everything you may encounter, but it is our intention and mission to set you up for success as best as possible. We don’t want your greenhouse to end up flat or blown away anymore than you do! And this is also why we reiterate,

There’s no such thing as too many anchors!