We feel polycarbonate is the best greenhouse covering due to its performance in extreme climates like wind, hail, snow and extreme temperatures. Growing Spaces® offers two types of polycarbonate glazing for the Growing Dome® greenhouse kit to accommodate different climates. 5-Wall glazing (16mm thick) is the standard for all our kits because it will perform well in all climates. Twin-Wall glazing (8mm thick) can be used if your average minimum winter temperature is 15 to 20 °F, or warmer (USDA climate zone 8b or warmer). Twin-Wall glazing is only available for the 15’, 18’, 22’, and 26’ Growing Dome kits.
Our polycarbonate glazing is 100% recyclable and manufactured in Houston, TX. Our kits have also been designed to reduce waste by optimizing the dimemsions to match the polycarbonate sheets. In order to further minimize waste and lower the price, two of our domes have polycarbonate triangles with seams in them. The 18′ and 26′ Growing Domes are the only kits manufactured with glazing panels that have a few tip taped triangles.
Side by Side Comparison
|Thickness||Twin Wall (8mm or 5/16in)||Multi Wall (16mm or 5/8in)|
|Wall Type||Twin||5-Wall RDC|
|Solar Heat Gain Coefficient||0.82||0.68|
Advantages of polycarbonate coverings
This greenhouse covering resists breakdown by ultraviolet light and harsh weather impacts, like hail. The greenhouse polycarbonate glazing has a life expectancy of over 20 years and comes with a 10 year pro-rated manufacture warranty for yellowing and hail damage. You and your plants will love the soft diffused light inside our Growing Dome greenhouses.
- Great light transmission
- Light diffusion/even light distribution – no harsh light or burning
- Made in the U.S.A.
- Resistance to U.V. rays
- Hail proof
- Energy saving
- Versatile, lightweight, and easy to install or replace
- Product contains pre-consumer recycled content
- May qualify for LEED Tax Credits based on your area
- Product is recyclable
- Durable and long lifespan if properly cared for
- 10-year pro-rated warranty
- High impact resistance (200 times greater than glass)
- RDC (Reinforced Double Co-extrusion) construction of 5-wall only
- Classified in accordance with ASTM-E84 and -D1929 standards
Polycarbonate Fact Sheets:
- Polycarbonate Product Details
- Material Safety Data Sheet (MSDS)
- Polycarbonate Burning Characteristics ASTM-E84
- Spontaneous Ignition Test ASTM-D1929
- Polycarbonate Burn Ratings ASTM-D635-98
- Fire Test
- Flame Spread Ratings
- Polycarbonate Care and Maintenance
- Chemical Compatibility Chart
Advantages of polyurethane tape
The polycarbonate seams are sealed with a 3M™ Polyurethane Protective Tape 8672 before January 1, 2021. It was an 8 mil, leading-edge erosion protection tape comprised of a tough polyurethane backing and an acrylic adhesive. Growing Spaces switched to a thicker, longer-lasting aircraft tape in 2021, manufactured by Berry and used by Boeing. It resists punctures, tearing and abrasion, and resists ultraviolet light. It can withstand a wide variety of difficult conditions, including rain, snow, hail and sand erosion. This tape is qualified for aerospace specifications.
- Formulated for resistance to ultraviolet light
- Tough, thermoplastic polyurethane elastomer has a high peel strength and is abrasion, scratch, erosion, tear and puncture resistant
- Thin and conformable tape is easy to apply and conforms over curved surfaces
- Acrylic adhesive adheres to a wide variety of substrates and retains a constant level of adhesion over time, yet removes easily when necessary
The tape is intended to prevent leaks in your Growing Dome. Some small leaks are acceptable, and you may also see drips caused by condensation inside the dome. But if you see a consistent leak, you may want to inspect your tape to make sure it is sealed properly and doesn’t show signs of degradation. In most conditions, the tape will only need to be replaced every 10 years as the UV protection wears off. Refer to our Maintenance Procedures.