Tag Archives: air movement

Roll Up Side Wall Considerations

Ventilation can either be done passively through openings or mechanically with fans. Roll up sides are an economical way of getting lots of air movement since no electricity is required. Roll up sides become even more effective when used on longer buildings. Roll up sidewalls are often used in combination with a small exhaust fan for early and late season ventilation when opening the sides is not practical.

If a structure is very exposed, it is best not to open more then 3’ in height due to potential of wind damage. If a structure is extremely sheltered, it is best to go even up to 6’ to create maximum opening. Roll up sidewalls are most effective when used in combination with peak end wall vents to create a “chimney effect” to draw warm air out of the building, especially when it is very calm. These vents are effective for air movement when outside temperature does not allow opening of the sides.

When a structure has a low profile, you will need to be careful during rainy periods due to moisture getting into the structure area. High profile structures (with straighter walls) usually work better with roll up sidewalls. When preventing a floor draft is an issue, the roll up mechanism can be raised and then the structure is lined with a skirt for the bottom 2’-3’. When using this method of ventilation, it should always be done on both sides. An effective use of this method includes opening the “downwind side totally and the opposite side on marginally.

Download our Roll up Side Wall Installation information sheet for more information

27'wide with Roll Ups roll up sides

The benefits of going to a bigger structure

What are some of the benefits of going with a bigger structure over a smaller structure?

Budget often dictates that someone needs to start small, especially when a person is just starting out as a grower with a greenhouse.
There is also the perceived notion that staying smaller means less heating cost. In itself, that is true, since heat loss is in direct proportion to surface area exposed to the outside.

As I have mentioned before, it is very important to weigh expense
against return.

A smaller air volume has less natural circulation.
Proper air circulation for plants is critical regardless of the season.
Think of a deep pond versus a shallow pond. The deep pond never has algae on the surface because of the increased movement.

Going with a taller greenhouse will automatically increase the circulation the same way.

Another point to consider with a taller greenhouse, is that there is more open space above the plants.

This open space is where moisture can go, away from the plants even before the greenhouse ventilation system does its job.

With a lower greenhouse, moisture is always in close proximity to the plants. In a taller structure, the plants will be dry much sooner.

Moist plants in a stagnant air mass are prone to disease. These plants will, as a result, produce less.

As always, be aware of the bigger picture.

Greenhouses 101: Climate and Air Effects on your Structure

You might be wondering, How does air volume affect the climate in a greenhouse? There also is the matter of air changes. What is the connection between shape and aerodynamics? You need to make sure it stays put.

There are 3 forces on every building which need to be considered if you want it to stay where you put it and in the shape you built it. There is down force (usually from snow build up), up lift (by wind) and lateral shift (both wind and snow). Mother nature is not restricted by lack of patience and will work away at any vulnerabilities in the structure, often without notice until it’s too late. There must not be any wiggle room that the weather can work on these vulnerabilities or things will come loose, unstable, and wear out faster..

There simply is no such thing as too many anchors. There are also various tips we can give you for ensuring that the plastic is tight enough to avoid wrinkling and flapping about, while balancing the issues of it being too tight. This can easily extend the life of your roof cover.

We also advise, especially this time of year, to cover the structure as soon as you can as the more snow you have on that spot which has to melt, the more moisture you will have in the building. The more moisture you have in the building the more condensation issues you will have. You want to give that ground the most time possible to dry up before you need to start using the building.

Contact us for more tips and considerations for building a structure that will stay put and have a longer life, we would be happy to help you.

Check out the presentation video and the rest of the series Norm spoke on Greenhouses 101 here. Stay tuned for the end of  January 2016 when he presents Greenhouses 202!

Roll Up Side Wall Considerations

Ventilation can either be done passively through openings or mechanically with fans. Roll up sides are an economical way of getting lots of air movement since no electricity is required. Roll up sides become even more effective when used on longer buildings. Roll up sidewalls are often used in combination with a small exhaust fan for early and late season ventilation when opening the sides is not practical.

If a structure is very exposed, it is best not to open more then 3’ in height due to potential of wind damage. If a structure is extremely sheltered, it is best to go even up to 6’ to create maximum opening. Roll up sidewalls are most effective when used in combination with peak end wall vents to create a “chimney effect” to draw warm air out of the building, especially when it is very calm. These vents are effective for air movement when outside temperature does not allow opening of the sides.

When a structure has a low profile, you will need to be careful during rainy periods due to moisture getting into the structure area. High profile structures (with straighter walls) usually work better with roll up sidewalls. When preventing a floor draft is an issue, the roll up mechanism can be raised and then the structure is lined with a skirt for the bottom 2’-3’. When using this method of ventilation, it should always be done on both sides. An effective use of this method includes opening the “downwind side totally and the opposite side on marginally.

Download our Roll up Side Wall Installation information sheet for more information

27'wide with Roll Ups roll up sides