ShadeMart 21 ft x 21 ft Blue Sun Shade Sail UPF50 Square - Breathable

In this review the ShadeMart 21 ft x 21 ft Blue Sun Shade Sail is evaluated for homeowners and outdoor hobbyists who need broad, breathable sun protection. The bottom line: this square UPF50 shade sail is best for patios, carports, pergolas and boat covers where durable UV blocking and airflow matter most. The reviewer found the woven HDPE fabric and stainless steel corner D rings deliver robust construction, while the water permeable design prevents pooling and reduces surrounding temperatures, making it a practical, low-maintenance canopy option.

Key Features

• Material: Woven HDPE fabric provides strong, tear-resistant coverage that holds up to wind and everyday outdoor wear.
• UV Protection: UPF50 design blocks up to 95% of harmful UV rays, helping to lower temperatures under the canopy by roughly 10 to 15 degrees.
• Breathability: The water permeable, breathable weave allows rain and air to pass through so water does not pool on the sail.
• Hardware: Stainless steel corner D rings attached to heavy duty white webbing simplify anchoring to poles, walls, or trees.
• Custom Sizing: Multiple custom size options let buyers choose a sail to fit patios, carports, pool areas, or irregular venues when measured carefully.
• Styling: The rectangle shape and blue color act as functional shade and a decorative element that can integrate with existing outdoor designs.

Who It's For

The ShadeMart 21 ft x 21 ft sail is aimed at homeowners, renters with outdoor areas, and small-property managers who want a durable, UV-blocking canopy that breathes and resists water pooling. It is particularly suitable for covering boats, patios, yards and carports where attachments like poles, trees or walls are available.

People who need a fully waterproof solution or who cannot anchor to nearby structures should look elsewhere; this style is explicitly not waterproof and depends on proper hardware and tensioning to perform best.

Pros & Cons

Pros

• High-density polyethylene fabric offers long-lasting durability and resists fading in sun-exposed applications.
• Blocks a large portion of UV radiation, improving comfort and protecting surfaces beneath.
• Water permeable design prevents ponding and allows ventilation, reducing wind stress on the sail.
• Stainless steel D rings and heavy webbing provide secure attachment points for typical hardware kits.

Cons

• Not waterproof, so it will not keep heavy rain fully out and is not suitable where a dry overhead cover is required.
• Custom sizing requires careful measurement; manual size variance is possible so buyers must measure accurately.

Specifications

Brand	ShadeMart
Shape	Square / Rectangle style
Size	21 ft x 21 ft
Material	Woven HDPE (High Density Polyethylene)
Corner Hardware	Stainless steel D rings on heavy duty white webbing
Functionality	Water permeable, breathable, UPF50 UV resistant

Our Verdict

The ShadeMart 21 ft x 21 ft Blue Sun Shade Sail is a solid value for anyone seeking durable, breathable sun protection with strong UV blocking. It performs well for patios, carports and boats when anchored correctly, offering a balance of airflow, color retention and hardware strength; choose another product only if you need a fully waterproof canopy.

Frequently Asked Questions

Is this shade sail waterproof?
The sail is water permeable and breathable, not waterproof, so it allows water to pass through instead of forming a tight barrier.

What hardware is used at the corners?
Each corner has a stainless steel D ring attached to heavy duty white webbing for secure anchoring with appropriate hardware kits.

Can it reduce temperature under the canopy?
Yes, the UPF50 fabric blocks up to 95% of UV and typically lowers temperatures under the sail by about 10 to 15 degrees.