ShadeMart 16 ft x 21 ft Green Sun Shade Sail UPF50 Rectangle - Heavy

In this review the ShadeMart 16' x 21' green rectangle sun shade sail is judged as a practical, heavy duty shading solution for patios, carports, and RV parking. The biggest reason to buy is its durable woven HDPE fabric and stainless steel corner D rings that deliver long-term sun protection without trapping heat. For anyone needing a large, breathable canopy that blocks up to 95% of UV rays while remaining water and air permeable, this shade sail offers a sensible balance of durability and airflow.

Key Features

• Woven HDPE fabric: provides strong tensile strength and resists fading while allowing air to pass through for cooler shaded areas.
• Stainless steel D rings: heavy duty attachments on white webbing give reliable anchor points for secure installation to poles, trees or walls.
• Water and air permeable: allows rain and breeze to pass through so water does not pool and ventilation is preserved under the canopy.
• High UPF protection: blocks up to 95% of harmful UV rays, noticeably lowering surface temperatures beneath the sail.
• Custom sizing available: a variety of custom sizes can be ordered to fit irregular outdoor spaces when standard sizes are not suitable.
• Rectangle styling: a simple shape that integrates with most outdoor designs and can be used over patios, pergolas, pools or carports.

Who It's For

The ShadeMart rectangle shade sail is best for homeowners and RV owners who need broad, dependable shade that stands up to regular outdoor exposure and strong breezes. Installers who want a breathable canopy for patios, carports, pools or pergolas will appreciate the combination of UV blocking and airflow.

It is less suitable for buyers who need a fully waterproof cover or require exacting color-match guarantees; customers should measure carefully before ordering and expect small measurement variations from manual cutting.

Pros & Cons

Pros

• Durable woven HDPE construction that resists fading and performs well in wind.
• Stainless steel corner D rings and heavy webbing for secure and long-lasting attachments.
• Breathable, water permeable design prevents pooling and keeps temperatures lower beneath the sail.

Cons

• Not waterproof, so it will not keep an area dry during heavy rain.
• Color can vary from expectations and some buyers report mixed color accuracy versus listing.

Specifications

Brand	ShadeMart
Shape	Rectangle
Size	16' x 21'
Material	Woven HDPE (High Density Polyethylene)
Corner hardware	Stainless steel D rings on heavy duty white webbing
Functionality	Water permeable, breathable, UPF50/blocks up to 95% UV
Use cases	Patio, carport, pergola, pool, yard, RV cover

Our Verdict

The ShadeMart 16' x 21' rectangle sun shade sail is a solid choice for anyone wanting reliable UV protection and airflow in a large canopy. Its heavy duty HDPE fabric and stainless attachments make it a durable, cost-effective option for patios, carports and RV covers, provided waterproofing is not required and buyers accept some color and size variation.

Frequently Asked Questions

Is this shade sail waterproof?
Answer. No, this style is not waterproof; it is water permeable and allows water to pass through rather than block it.

Will it reduce temperature under the canopy?
Answer. Yes, the fabric blocks up to 95% of UV rays and commonly lowers temperatures by around 10 to 15 degrees in shaded areas.

Can it be attached to trees or poles?
Answer. Yes, with the proper hardware kits the stainless steel D rings and webbing let you attach the sail to poles, trees, walls or roofs.