17 ft x 21 ft Sand Beige Rectangle Sun Shade Sail - Cooling UPF50

In this review of the ShadeMart 17' x 21' Sand Beige Rectangle Sun Shade Sail, the bottom line is simple: it is aimed at homeowners and DIYers who need large, breathable sun protection for patios, carports or boats and want a durable fabric that cuts heat and UV without trapping moisture. The most compelling reason to buy is the woven HDPE fabric that blocks up to 95% of UV while remaining water permeable and breathable, which keeps covered areas noticeably cooler and avoids pooling during rain.

Key Features

• Material: Woven HDPE fabric provides strong tensile strength and resists tearing while offering long-term sun protection.
• UV Protection: Blocks up to 95% of harmful UV rays and helps lower temperatures under the canopy by around 10 to 15 degrees.
• Breathability: The water permeable design lets air and rain pass through so water does not pool on the surface and ventilation remains good.
• Hardware: Stainless steel corner D rings attached to heavy duty white webbing offer sturdy attachment points for common mounting kits.
• Customization: Available in multiple sizes and colors with custom options so it can be tailored to nonstandard venues when measured accurately.
• Versatility: Can be mounted to poles, trees, walls or roofs to shade patios, carports, pergolas, pools and yards.

Who It's For

This shade sail is best for homeowners, boat owners and property managers who want a large, breathable canopy to reduce sun exposure and heat across patios, carports or open seating areas. People who value durability and simple installation with standard hardware kits will appreciate the stainless steel D rings and heavy webbing.

It is less appropriate for buyers who need a fully waterproof shelter or who require a rigid structure; this style is explicitly water permeable, so it will not keep out driving rain as a sealed tarp would.

Pros & Cons

Pros

• Excellent sun protection that blocks most UV and noticeably lowers temperature under the sail.
• Durable HDPE fabric and stainless steel D rings give confidence in wind and weather resistance.
• Breathable, water permeable design prevents water pooling and promotes airflow beneath the canopy.
• Custom size options and multiple colors make it adaptable to a variety of outdoor spaces.

Cons

• Not waterproof, so it will not serve as a rainproof cover for fully dry shelter.
• Shade sails require correct measurement and proper hardware to achieve the best tension and fit.

Specifications

Shape	Rectangle
Size	17' x 21'
Material	Woven HDPE (High Density Polyethylene)
Corner Fittings	Stainless steel D rings on heavy white webbing
Functionality	Water permeable, breathable, UV resistant
UV Block	Up to 95% UV rejection
Customization	Custom sizes available; measure before purchasing

Our Verdict

The ShadeMart 17' x 21' rectangle shade sail is a practical, value-oriented choice for anyone needing large-area sun protection that breathes and stands up to outdoor conditions. It is especially good where ventilation and UV blocking are priorities, and it offers durable fittings for repeated seasonal use; buyers who need complete waterproofing should consider a different product.

Frequently Asked Questions

Is this shade sail waterproof?
No. This style is water permeable and designed to allow rain to pass through rather than form a waterproof barrier.

How much UV protection does it provide?
The fabric blocks up to 95% of harmful UV rays and helps lower temperatures beneath the sail.

Can it be attached to trees or poles?
Yes. With appropriate hardware kits the D rings and webbing allow attachment to poles, trees, walls or roofs.