ShadeMart 17ft x 21ft White Sun Shade Sail UPF50 Rectangle

In this review of the ShadeMart 17' x 21' white sun shade sail, the bottom line is simple: it is a heavy duty, breathable rectangle canopy best for homeowners and small businesses who need reliable UV protection and airflow without creating a waterproof cover. The reviewer found the woven HDPE fabric and stainless steel D rings make installation straightforward and durable, while the water permeable design lets rain and breeze pass through so it lowers temperature and avoids ponding. This is a practical choice when shade, durability, and appearance matter more than full waterproofing.

Key Features

• Woven HDPE fabric: provides strong UV protection while remaining breathable so heat is reduced and air circulates under the canopy.
• Stainless steel D rings: are attached to heavy duty white webbing to give reliable anchor points for long-term tensioning and repeated use.
• Water permeable design: allows water to pass through the fabric, preventing pooling and reducing wind load on the sail during storms.
• UPF50 protection: blocks up to 95% of harmful UV rays to help lower temperatures by roughly 10 to 15 degrees under shade.
• Custom size options: available in multiple measurements so buyers can choose a rectangle that matches patios, carports, pergolas or pool areas.
• Decorative styling: the clean white rectangle integrates with outdoor design and can be mounted to poles, trees, walls, or roofs with proper hardware.

Who It's For

The ShadeMart 17' x 21' rectangle sail suits homeowners, boat owners, and small commercial spaces that need broad UV protection without a solid roof; it works well over patios, carports, pergolas and pool seating where airflow and reduced heat are priorities. Installers who plan to anchor to existing structures like trees, poles, or walls will appreciate the reinforced D ring corners and heavy webbing.

It is not the right choice for buyers who need a waterproof canopy or full rain protection, or for users who require exact inch-perfect bespoke seams for structural roofing; the product is designed for breathable shade and may have small variations in side lengths due to manual measurement.

Pros & Cons

Pros

• Durable woven HDPE fabric that keeps sun off sensitive areas and holds up to wind and hail reported by customers.
• Stainless steel D rings and heavy webbing provide sturdy anchor points for secure installation.
• Breathable, water permeable construction prevents water pooling and reduces heat beneath the sail.
• Custom size options and clean styling make it flexible for many outdoor spaces.

Cons

• Not waterproof, so it will not keep areas dry during heavy rain or be a substitute for a solid roof.
• Manual measurement tolerances mean side lengths may vary slightly, requiring careful measuring before purchase.

Specifications

Brand	ShadeMart
Shape	Rectangle
Size	17ft x 21ft
Material	Woven HDPE (High Density Polyethylene)
Corner Hardware	Stainless steel D rings with heavy duty white webbing
Functionality	Water permeable, breathable, UV resistant (UPF50)
Typical Use	Patio, carport, pergola, pool, yard, window shade

Our Verdict

The ShadeMart 17' x 21' white rectangle sail is a practical, value-minded choice for anyone who needs durable UV protection and airflow for outdoor spaces; its woven HDPE and reinforced corners make it reliable for long-term shade, while the water permeable design avoids pooling. Choose this if you want solid sun blocking and breathability, but look elsewhere if you need a waterproof canopy.

Frequently Asked Questions

Is this shade sail waterproof?
No. The fabric is water permeable and breathable, so it allows water to pass through rather than creating a waterproof cover.

How much UV protection does the sail provide?
The sail blocks up to 95% of harmful UV rays (UPF50), which helps reduce temperature under the canopy by roughly 10 to 15 degrees.

Can it be attached to trees, poles or walls?
Yes. With appropriate mounting hardware, the stainless steel D rings and heavy webbing let the sail be attached to poles, trees, walls or roofs.