Norm wants to caution anyone modifying their tunnel (or any structure) as this compromises the entire concept of the structure as well as voids the warranty and can start a whole host of other issues. Please call and speak directly with Norm, as well as read ALL the material on our website and installation manual before embarking on what can be economical and easy to use season extenders, or, very costly mistakes. Thank you for your interest
One of our most popular structures is the hanley tunnel because it is the cheapest way of covering an area for season extension.
As a way of addressing some of the challenges and limiting factors with the tunnels, we have come up with a modified hanley.
The two areas where it significantly improves on the regular tunnel are the side clearance and the peak for snow shedding. Instead of using 24’ of steel to make 17’ wide and 7’6” high, we are using 26’ of material to make 16’ wide and 9’ high. It still uses 28’ wide plastic with extra at the ends to make the same kind of “tails”.
Sliding the plastic up on the sides is still the way that the tunnel is ventilated and you will still have the same challenges as far as creating access.
The re-bar anchors, base plates, clasps and rope are the same on the modified hanley as they are for the regular tunnel. We supply 5’ more of extra plastic for the tails since the building is taller.
The peak on the end hoops are very hard on the plastic, so we have designed a more rounded hoop at each end. It is strongly recommended to have 3 guides ropes at each end to brace back to the anchoring posts of the plastic.
Any structure with ends is not considered a Hanley Tunnel. We are more than willing to discuss the differences and benefits/drawbacks between tunnels and cold frames should you wish to know more.
The main thing which is critical to understand before going with a modified hanley is the extra wind load which the structure will be subjected to. Going from 7’6” to 9’ high, results in a 40% increase in the wind load. This issue is what makes the correct tightness of the ropes an even more critical consideration.
It is also the reason why we strongly urge customers who
do not have any tunnel experience to start with a regular tunnel.
The first area to discuss regarding season extension are those structures that are simple enough to disassemble and relocate to another spot-primarily referring to Hanley Caterpillar Tunnels.
The real lure of these buildings is their low cost and simplicity to move. Generally the area is prepared in advance and then the tunnel is moved over the area when the planting is to be done.
Since the original design specified 6′ hoop spacing, the intent was always to remove the cover before risk of heavier snow fall. More often now, growers are going to 5′ spacing (and sometimes 4′) to allow the covers to remain on longer or even permanently.
By having a smaller hoop spacing, it allows the cover to stay on permanently, which allows for a much earlier start in the spring.
The key to the concept of the hanley working is in the rope.
- The back and forth pattern of the rope resembles the way a person would lace up a boot.
- Typically there is a spring loaded clip at the base where the rope passes through.
- Once the rope is fully installed, it is important to tighten it through three passes from end to end.
- If the rope is not tight enough, the wind will create wiggle and movement sideways.
- When the plastic is tight enough, it also allows the grower to slide the plastic up the hoop to allow ventilation.
Generally the plastic is about 25′ longer then the tunnel.
This allows the installer to bunch up (pig tail style) the extra poly at both ends between a pair of posts.
It is important to get the plastic as tight as possible lengthwise first.
There must also be a rope from the top of the last hoop to the tie off post.
There are a couple of challenges to consider with the hanley tunnels.
- One of these challenges is to create a proper entrance. Typically entrance is achieved by slightly lifting the plastic and ducking underneath.
- The other are of challenge is the low shoulder height of the structure. This restricts the use to a couple rows of taller items in the middle and a couple rows of shorter plants along the side. The width of the tunnel does lend itself to three regular size beds.
Once you have learned about the nuances of the hanley tunnels, and asked any questions that come up, you will be better prepared to have these efficient season extenders work for you and your application.
Feel free to look at our Hanley Application page for more information and photos, and give us a call with anything else you require.
We are pleased to have many happy customers these structures are working for, and look forward to you being next!
Check out our new book if you want to know more “So You Want to Buy a Greenhouse…Your Guide to Planning a Greenhouse Purchase”
Norm shared some nostalgia after Coffee Time with Norm recently. Check out his story here: