Awnings: Conventional awnings attach to buildings and cannot project out more than a few feet due to their inherent limitations with strong wind gusts. While retractable awnings can extend further, they must be reeled in to prevent wind from destroying them. By contrast, we projected permanent shade sail awnings out more than 50′ from buildings where code required they withstand 90 MPH 3-second gusts.
Canopies: The only features that tension structures share with conventional sun canopies is that both are free standing (i.e. stand alone) and are permanent. Here are the advantages of cable-tensioned structures. (This comparison ignores temporary, “pop-up” canopies. which serve entirely-different market needs).
a. Cable-tensioned structures can have greater distances between columns (i.e. clearspan). This enables them to have fewer obstructions and cost less. For example, we did a hip-roof canopy project in Oakland, CA where a single fabric measures 67’x36′ for a total covering of 2,412 square feet. It has only (6) columns, which averages 402 square feet per column. This structure is 1/2 mile from the San Francisco Bay, where building code requires it withstand 85 MPH 3-second wind gusts.
b. Tensioned shade cloth structures don’t need horizontal beams, unless they’re cantilevered. Trusses are also unnecessary. This too enables them to cost less.
c. Tension structures can be cantilevered, whereas traditional canopies cannot because their aluminum poles and frames aren’t strong enough. Being structural steel, we routinely project tension structures 18′ out from their columns in parking lots. Greater distances are possible.
d. Conventional canopy roofs are typically impermeable fabric, metal, fiberglass or wood. These trap hot air inside the structure, whereas the mesh fabrics on tension structures lower air temperature as hot air rises between woven yarns.
e. The maintenance costs of tension structures are less because they don’t rot or mildew. HDPE yarns don’t absorb water.
f. Shade sails win the prize when it comes to aesthetic appeal. Dramatic height variations; fabric “warping” ; overlapping; multiple polygon shapes & colors; & the interesting curves (both fabrics and their shadows) are just some of the visual advantages that enhance landscape appeal.
2. How much UV protection do tension sun shade shelters provide?
Up to 97% of the sun’s UVA and UVB rays are blocked, depending upon shade cloth color. See sun safety for information about this importance.
3. How do tension sun shade shelters lower temperature?
Hot air rises out the top between the knitted yarns of High Density Polyethylene (HDPE). This draws outside air into the structure from the sides, which creates continuous air movement. That’s why cable-tensioned fabric shade canopies, shade sails, and permanent shade umbrellas reduce ambient air temperature up to 20 degrees. By contrast, hardened roofing materials (i.e. metal, wood, plastic, tile, stone, etc) and conventional awning fabric traps hot air inside the structure.
4. How does the cost compare with structures having roofs of hardened materials?
The purchase price of tension sun shade shelters is considerably less for same-size structures of comparable quality. Installation price is only a fraction and sites are disrupted for only a few days because structures arrive prefabricated. There are no maintenance costs, except for the occasional hosing to remove dirt and bird droppings.
5. How durable are your sun shade shelters?
Steel columns and frames are warranted for 20 years. They’re factory-welded to be watertight and are protected with a powder coat finish. (See above photo). There’s a limited 10-year warranty on the HDPE fabrics. All are designed to withstand 3-second wind gusts of at least 85 MPH with the fabrics attached. Our structures meet California Building Code, which is the world’s toughest. They are approved by GSA for use by the U.S. Government. Finally, many of our shade canopy designs are pre-approved by DSA for use at California’s public schools.
6. What’s the difference between cable-tensioned shade canopies and shade sails structures?
Our shade canopies, shade sails and giant shade umbrellas are all permanent “tension sun shade shelters” a.k.a “tension fabric shade structures.” However, canopies have an upper steel frame, over which shade cloth is tensioned into various roof shapes. Shade sail structures don’t have upper frames. They only have columns, shade sails and the hardware to attach them and maintain proper tensioning.
7. Can shade sails and canopy fabrics be removed?
There’s no structural reason for removing them unless snow is expected. A 2-man crew can remove each shade canopy and shade sail in less than one (1) hour and reattach them in less than two (2) hours.
8. What maintenance is involved?
None, except for an occasional hosing to remove dirt and bird droppings. Nothing rusts because our factory welds all structural steel to be water-tight. It then bakes on a UV-resistant powder coat finish. When constructing, we caulk all seams where steel members are field-bolted together. We also caulk behind all washers. Shade cloth yarns, being made of High Density Polyethylene, won’t rot or mildew because they don’t absorb water.
9. What is a cantilevered structure?
Shade canopies are “cantilevered” when horizontal beams extend beyond vertical columns to remove safety hazards (e.g. car parking lots or porte-cocheres) or visibility barriers (e.g. bleacher covers). See cantilever shade structure photos.
10. How much area can your shade structures cover?
As large as can be imagined.
11. What is “clear span?”
The distance between columns. For example, a basketball court requires “clear spanning” the entire court width.
12. Are building permits required?
All California municipalites require building permits because they classify in-ground shade structures as permanent buildings. (Some will waive this requirement if the shade canopies or shade sail structures will be used for agricultural or nursery purposes). We provide designs and structural calculations certified by our California engineer to comply with community-specific adaptations of the California Building Code.
All California communities require that fabrics be preapproved by the California Fire Marshal before issuing permits, even if these fabrics meet National standards for flame retardancy. We encountered numerous situations over the years where people purchased shade structures from other companies assuming they could later get building permits from their cities. But they couldn’t because their manufacturers shipped fabric that wasn’t approved by the California Fire Marshal. The buyers didn’t know it was necessary until too late, and their manufacturers didn’t tell them otherwise. In fact, most out-of-state manufacturers don’t provide it because the requirement is unique to California. The testing process is expensive. The standards are so high that many companies can’t pass it even with fabrics that meet National standards.
See the photo of the shade structure frame on the right? Another company supplied and constructed it at a private preschool in Los Angeles County in Fall 2009. Six months later, the city building inspector discovered it and mandated that it be removed because a building permit hadn’t been secured prior to construction. It hadn’t been professionally engineered, approved or inspected by the city. The inspector made the owner remove the fabric immediately because it wasn’t approved by the California Fire Marshal. The owner now seeks a contractor that will remove the entire structure and replace it with one that’s engineered and permitted. (Imagine the challenge of excavating new foundations without ruining the synthetic turf!).
The engineering process to meet California code usually determines that steel be more-robust than fabricators otherwise provide for unengineered structures. Furthermore, the reinforced foundations specified by the engineering process are typically bigger. This results in higher fabrication and construction pricing, but this is ultimately cheaper than replacing the structure after running afoul of city hall.
All of our fabrics are approved by the California Fire Marshal and meet National standards.
The permitting authority and process differ for California public schools (i.e. K-12 and Community Colleges), which have building codes stricter than California municipalites. This includes privately-owned day care centers and charter schools on public school property). The permitting authority is the California’s Division of State Architect (DSA).
We provide a full line of school shade canopies already approved by DSA. While DSA will approve all of our shade structures, the process is faster and less-costly if already on this pre-approved list.
13. Are your fabrics flame retardant?
Yes, all are on the list of fabrics approved by the California Fire Marshal. (see question #11 above). They also meet the National standards for flame retardancy (i.e. ASTM E84 & NFPA 701).
14. Are your shade structures waterproof?
They can be if we use PVC-coated fabric. But shade cloth (aka HDPE knitted fabric) is preferable for most California applications. It’s water resistant, meaning that most rainwater (i.e. 90%+) will shed as though “waterproof”. This is due to its pitch (i.e. “slope”) and drum-tight tensioning. In fact, only fine mists will come through the fabric during intense rainstorms. Besides, rain comes in from the sides anyway because it seldom falls straight down from the clouds. Why spend so much more for PVC fabric, which traps hot air inside the structure like conventional roofing materials?
15. For what wind velocity are your structures designed?
A minimum of 85 MPH 3-second gusts. Most California communities require less; but some require more. For example, we did a project in Ontario, CA where code required the structure to endure 110 MPH 3-second gusts with fabrics attached. Regardless, we always comply with local code.
16. Can your shade structures be bolted to existing concrete patios?
Most permanent shade canopies and all shade sail structures require concrete pier footings. But, we can bolt canopies to existing patios if the concrete is reinforced; at least 6″ thick; and the uncantilevered structure doesn’t exceed 400 square feet in size.
17. What are your design specifications?
See shade structure specifications.