One of the ways to help people understand greenhouses and the care that we put into them is to help them understand what each component of them is and what its function is. To do this we have included a section of this web site to ensure there is a common understand of the various aspects and parts of a greenhouse.


BW Greenhouse 'Arch' FAQs

An arch is a curved piece of structural steel that forms the primary shape of a Freestanding Greenhouse (also know as a Cold Frame Greenhouse or Hoop Greenhouse). The curvature of the arch dictates its wind and snow loading capacities. BW has optimized its arch curvatures to maximize interior growing room without compromising on their wind and snow capabilities.

The shape of the steel tube also helps determine its strength. BW Greenhouse® does not use either round or oval arches as they are not, in our opinion, as structurally stable or strong as a comparable square or rectangle arches. Arches are strongest if they stay in plane when under snow or wind loads. Square and rectangle arches naturally resist the torqueing better under snow and wind loads.

In addition to the shape of the steel tube used (square or rectangle), one needs to pay attention to the gauge of the steel and is yield strength. Clients regularly tell us that our Greenhouses are the strongest on the market. BW uses Gatorshield Steel from Atkore (Allied) Steel. This steel has a minimum of a 50,000 lbs yield strength. By way of comparison, most hot-dipped steel has a yield strength of only 32 – 34,000 lbs.

The weather patterns globally have changed quite dramatically over the last few years. BW Greenhouse recognizes that building codes often are not changed for may decades, so relying on them alone to determine what design specifications to build to is taking an unnecessary risk. Storms are becoming stronger, more frequent and bring more snow. In many regions, the one in 50 year storm has become a one in 10 year storm.

As a result, BW recently up-gauged the steel in its major structural components, because we realize that for many of our clients, their Greenhouses are a source of income. Losing a Greenhouse to weather, means not only having to replace the Greenhouse, but also having to replace the crop and equipment inside as well as forfeiting a year’s revenue on top of that. This is why we design the strongest Greenhouses on the market (our clients tell us this regularly).



BW Greenhouse 'Anchor' FAQs

An anchor is a specially designed structural component used to hold a Greenhouse in place on a concrete foundation. These foundations could include a footing, pile footing, strip footing, or concrete blocks.

There are two different kinds: mechanical or chemical. BW has partnered up with Hilti Industries to provide our clients with Hilti TZ seismic anchors to ensure that the Greenhouse remains stable no matter the conditions. In instances where the anchor ends up to close to the end of concrete foundation, BW will specify the use of epoxy and treaded rod in order to ensure there is no fracturing of the concrete.



BW Greenhouse 'Baseboard' FAQs

An industry leading innovation from BW Greenhouse® is our galvanized steel baseboards. These baseboards are used at the bottom of our arches to provide additional rigidity to our structures and to provide a surface to seal the bottom of the Greenhouse to as well as to attach different components to including roll-up sides tubes.

Our clients tell us that our galvanized baseboards are one of the best options we offer. They are strong and greatly reduce the maintenance of the greenhouse. Our use of steel baseboards means we no longer have any wood components in our structures, which allows us to offer one of the only Certified Organic compliant Greenhouses on the market.



BW Greenhouse 'Clip' FAQs

Clip is an aluminum extrusion that is used as a base to anchor polyethylene covering to a Greenhouse or on a roll-up side. Clip is used on round profiles of steel generally used as roll up side or purlins.

BW has custom designed this extrusion to make sure it is deep enough to put multiple layers of polyethylene or shade cloth in it.

Aluminum clip is far superior to formed steel bases as these bases can lose their shape over time and corrode.


Cross Tie

BW Greenhouse 'Cross Tie' FAQs

A cross tie is a horizontal piece of steel that connects two arches. This component keeps the two arches from moving separately, giving the arch additional strength. Cross ties can also be used to hang baskets or irrigation lines from.

BW uses cross ties in all of our Freestanding Greenhouses (also known as Hoop Greenhouses or Cold Frame Greenhouses).



BW Greenhouse 'Crank' FAQs

For BW, a crank is a self-locking mechanism used to roll up the sides of a Freestanding (Hoop or Cold Frame) Greenhouse. Our cranks use a 4:1 ratio to make them easier to operate even if the roll-up sides are several hundred feet long.


Cold Frame Greenhouse

BW Greenhouse 'Cold Frame Greenhouse' FAQs

A Cold Frame Greenhouse is a Freestanding or Hoop Greenhouse that is not heated. These Greenhouses generally have a smaller on-centre arch spacing needed for the additional snow carrying capabilities.

BW Greenhouse’s Cold Frame Greenhouses are considered by most of our clients to be the strongest on the market.



BW Greenhouse 'Coverings' FAQs

Coverings are fairly self-explanatory – they are what Greenhouses are covered with.

There are generally three different kinds of coverings used on Greenhouses: polycarbonate, polyethylene and glass. (BW Greenhouse® does not use any glass in our Greenhouses, because we do not feel that the cost, weight, lack of light control and dangers associated with glass warrant its use).

Instead, we use both polycarbonate and polyethylene.

Our exclusive global partner for our polycarbonate is Palram Industries. (See our Partner page for more information on Palram). Polycarbonate is an amazing material. It comes in a number of different colours and profiles. Its ability to control light is dependent on the resins used as well as the coatings applied. One of the most exciting developments from Palram The science now used in coverings has dramatically changed Controlled Environment Growing. Yields and quality of product have marked improved using both polyethylene and polycarbonate coverings. Incredibly high levels of diffusion and light spectrum control.


Curved Purlins

BW Greenhouse 'Curved Purlins' FAQs

Curved Purlins are pieces of steel that run horizontally attaching one arch to another. They are curved away from the poly.


End Wall

BW Greenhouse 'End Wall' FAQs

An end wall is a solid end to a Greenhouse that is made of either polyethylene or polycarbonate. An end wall can have a sliding door in it for easier access and additional ventilation.


Energy Curtain

BW Greenhouse 'Energy Curtain' FAQs

An energy curtain is a heavy shade system that can be deployed at night or in low temperature situations to reduce the amount of heat that is lost through the Greenhouse covering.


Energy Truss

BW Greenhouse 'Energy Truss' FAQs

An energy truss is a horizontal truss used in GUTTER Greenhouses to add additional load carrying capabilities to the structure. Energy trusses are used to hang crops from, frame shading systems or energy curtains.


Flat-bottom Bracket

BW Greenhouse 'Flat-bottom Bracket' FAQs

Flat Bottom Brackets are steel posts welded to plate steel to be used to anchor a Greenhouse or Shelter to a concrete or steel foundation. When anchoring into concrete, BW GLOBAL provides Hilti TZ Seismic Mechanical Anchors for their holding power and ease of use.


Freestanding Greenhouse

BW Greenhouse 'Freestanding Greenhouse' FAQs

A Freestanding Greenhouse can also be known as a Hoop Greenhouse or Hoop House as well as a Cold Frame (when it has no external source of heat).

BW Freestanding Greenhouses can withstand tremendous snow and wind loads due to their arch curvature (GOTHIC) and shape (SQUARE and RECTANGLE rather than round or oval) and materials (Gatorshield steel with 55+ksi yields).

Freestanding Greenhouse tend to be more economical than GUTTER Greenhouses but can sometimes cost more from a labour and heating perspective than the contiguous space offered by a GUTTER Greenhouse.



BW Greenhouse 'Footing' FAQs

A footing is a concrete foundation designed to hold the vertical forces (both downwards and upwards) placed on a Greenhouse from wind and / or snow.

All BW Greenhouses and BW Shelters require concrete footings (either strip or pile). This is to protect them from wind uplift and to provide a moment connection for the arch that will add to its stability (strength).

BW GLOBAL specifies Hilti TZ seismic mechanical anchors.



BW Greenhouse 'Foundation' FAQs

A foundation is a structural base that is used to hold the Greenhouse in place. These foundations are generally constructed out of concrete. The concrete can be formed into pile footings, strip footings or precast concrete blocks.

Contrary to common belief, ground posts pounded into soil are not sufficient to anchor a Greenhouse down. This method does not protect the Greenhouse from uplift and does not offer the arches much lateral support. Not anchoring your Greenhouse to concrete will invalidate the warranty.


GatorShield® Steel

BW Greenhouse 'GatorShield Steel' FAQs

GatorShield® is a proprietary steel by Atkore (Allied) Steel that has a very high yield strength and is extremely corrosion resistant (100 hour salt spray).

BW uses this steel rather than Galvalume or other pre-galvinized steels, because of its physical properties and the fact we have found that the GatorShield coating is much better and does not discolour polyethylene coverings.


Ground Posts

BW Greenhouse 'Ground Posts' FAQs

Ground posts are sections of steel that are set into concrete and slide into the arches to hold the Greenhouse down.

Contrary to common belief, ground posts pounded into soil are not sufficient to anchor a Greenhouse down. This method does not protect the Greenhouse from uplift and does not offer the arches much lateral support. Not anchoring your Greenhouse to concrete will invalidate the warranty.


GUTTER Greenhouse

BW Greenhouse 'GUTTER Greenhouse' FAQs

A GUTTER Greenhouse is a Greenhouse that has gutters running along the sides of a bay to collect water and to attached to another bay. A series of bays can be attached to each other to make a large contiguous growing area.

The advantages of a GUTTER Greenhouse is more efficient use of available ground for growing, more efficient heating and greater labour savings.

GUTTER Greenhouses are used by large commercial growers and by Retailers who want to increase their profits.



BW Greenhouse 'Header' FAQs

A header is a piece of steel that goes across the top of a door to support the door track.


Hobby Greenhouse

BW Greenhouse 'Hobby Greenhouse' FAQs

A hobby Greenhouse is a Freestanding, Hoop or Cold Frame Greenhouse that is used by hobby growers. Generally, they are smaller in width (12’ or less).


Hoop Greenhouse

BW Greenhouse 'Hoop Greenhouse' FAQs

A hoop Greenhouse is simply a Freestanding or Cold Frame Greenhouse by a different name. It is characterized by having arches (or hoops) that go from the ground to the top of the Greenhouse.



BW Greenhouse 'Lock' FAQs

Clip is an aluminum extrusion that is used as a base to anchor polyethylene or shade covering to a Greenhouse.. Wire (or wiggle wire) is inserting into the profile to accomplish this. Lock is screwed into the flat edge of a square or rectangular shape of steel used in arches or baseboards.

BW has a custom designed extrusion that is deep enough to put multiple layers of polyethylene or shade cloth in it.

Aluminum lock is far superior to formed steel bases as these bases can lose their shape over time and corrode.

Lock is usually used on flat surfaces, such a square or rectangular structural steel tube.