Split System -
Upper & Lower are both Top Down

Single - Top Down System

Split System -
Upper Curtain - Top Down
Lower Curtain - Up Only


  • Heavy structural 1˝ O.D. on both top and bottom
    of curtain

  • For smooth up and down movement of the curtain and a non-sag curtain top we have selected a heavy galvanized 1˝ O.D. structural tubing (about 2 1/2 times as heavy as 1/2˝ conduit normally used). We also use 20´ lengths rather than 10´ as normally used with conduit. This substantially reduces the number of connections and potential problems resulting from loose connections. We recommend a hem pipe at the top and the bottom of the curtain. The bottom hem pipe holds the curtain without permanently fastening to the building. This provides convenient access for maintenance and cleaning of the curtain and building, as well as fair weather overhead storage. Hem pipe splices are internal for a smooth continuous outer surface.

    To properly secure the heavy 1˝ top hem pipe to the cable drop line, we have designed a rugged galvanized steel clamp. The design of this clamp features a simple and easy drop line cable adjustment.


  • Galvanized aircraft cable on all drop lines and main lines

  • For strength and durability, all the drop lines are 1/8˝ (7x19), flexible aircraft cable. The main lines are 3/16˝ aircraft cable; 1/4˝ available where required.

    We recommend 2˝ x 1˝ 14 gauge welded wire. This galvanized product is more rigid than plastic products and is less restrictive to air flow. Tensar polygrid® is available but only recommended for gable or overshot ridge applications.



  • Heavy duty steel pulleys with oil impregnated
    bronze bearings to insure life time self-lubrication.
    Pulleys mounted on rugged 3-lag bracket.

  • For a high level of performance and long life we have selected the highest quality pulleys available. Both the drop line pulleys and main line pulleys have galvanized steel side plates and zinc plated steel sheaves with oil-impregnated bronze bearings. Also, for ease of installation and system durability, we provide a rugged galvanized pulley mounting bracket for both the drop line and main line pulleys. Special pulleys are available for inside and outside exterior corners, for thruwall interior mounting of controller, for counterweight and for unique cable routing needs. All steel surfaces are zinc plated or galvanized.


  • Heavy duty manual winch or automatic controllers
  • Two sizes of hand winches are available. Standard duty for curtains <600 sq. ft. Heavy duty w/autobrake for all other curtains. Two
    electric controllers are available.
    The standard Norbco Curtain Controller operates curtain movement by winching the mainline cable around a grooved drum
    controlled by a thermostat and timer. This unit is widely used in poultry, hog and dairy operations.
    Norbco also manufactures a heavy duty electric controller, a unit which will satisfy the most critical demands for longevity,
    flexibility, and quality.


  • Reinforced heavy duty translucent vinyl
    with a high UV inhibitor formula
  • Heavy Duty translucent polyethelene


  • Galvanized shelf brackets angle up at 45°. In windy situations the bottom of the curtain can lift slightly up and away from the building. Once the pressure is relieved the curtain gently falls back to its neutral position.
  • Curtain is kept in place with standard zig-zag cord. In areas with high wind conditions we recommend either 1” pipe or 2” strapping and tensioners
  • These uniquely designed brackets eliminate the need for installing treated wood shelving, which often shrinks and warps over time. Wood shelves also trap moisture and bedding in the curtains. The brackets are made from 1/4˝ galvanized steel. The brackets are installed 3´ o.c. and provide support for the curtain as well as securing the retainer line.

Unique Sidewall Curtain for
High Sidewall Dairy Barns


Top curtain fully raised -
“Blizzard Position”

Top curtain slides up & down in front of bottom curtain -
“Cold Weather Ventilation Position”

Both curtains roll up for storage Top curtain not yet in
storage position -
“Heat Wave Position”

  • Top curtain slides up & down for cold weather
    ventilation. Cold air enters the building over the
    top of this curtain, then mixes with the warmer
    air inside before being exhausted.
  • Both curtains roll-up for storage
  • No shelves to accumulate debris
  • Curtain fabric is either flat or rolled. Stays cleaner,
    lasts longer
  • Unlike other split curtains the SLIDER SYSTEM
    has no center plank or shelf. This wide open
    design provides:
    • minimum air restriction
    • maximum air flow

  • Reinforced heavy duty translucent vinyl
    with a high UV inhibitor formula
  • Heavy Duty translucent polyethelene

  • Keder tube is a 2” aluminum extrusion which
    replaces the traditional hempipe.
  • Instead of 4” hems on the fabric, a nylon rope is
    welded at the top and bottom edge of the curtain.
  • Rather than pushing 200’ of hempipe through a
    4” hem simply hang the top keder tube, then
    slide the curtain into the opening. Once the
    curtain is hanging, slide the bottom keder tube
    over the rope hem at the bottom of the curtain.
    • less weight
    • easier installation
  • Two heavy duty, 80:1 right angle gearboxes roll up the top & bottom curtains. A shepherd’s crook attaches to the input shaft. A 3/8˝ electric drill (furnished by the owner) provides the power. An optional motorized gearbox (shown in photo below) makes this operation even easier.
  • Nylon rollers prevent the gearbox assembly from binding as it easily moves up or down the galvanized guidetube. You can roll up a 200' curtain in less than 5 minutes.
  • Galvanized Endwall Covers are included with the system. These covers protect the guidetube & gearbox assemblies from the elements as well as preventing wind damage to end of curtain (covers available in stainless steel)
    • A standard system includes one dead end cover permanently fastened to the building and one drive end cover hinged to provide easy access to the gearbox assemblies.
  • Very long systems will have two dead end covers with the drive cover located in the center.
  • 2" wide nylon strapping with tensioners installed 5´ on center are far superior to zig zag cord for protecting the curtain in high wind conditions.
  • Top curtain can be controlled with a manual winch or automatic controller and thermostat. All top curtain hardware has been used on conventional Norbco Flexwall Curtains for over 15 years.
  • Can be installed on greenhouse, fabric covered, timber column or pre-engineered steel buildings. Many farmers have chosen to add the roll-up storage feature to their single, lift up curtains.