ShadeMart 20 ft x 21 ft Black Sun Shade Sail UPF50 Rectangle - Durable

In this review of the ShadeMart 20' x 21' rectangle shade sail we look at who should consider this canopy and why it stands out. The bottom line: this is a heavy-duty, breathable sun sail best for homeowners and RV or carport owners who need reliable UV protection and airflow rather than a waterproof cover. The sail's woven HDPE fabric, stainless steel D-rings and reinforced webbing deliver solid build quality and sun blockage, making it a practical choice for patios, pergolas and vehicle covers.

Key Features

• Woven HDPE fabric: The high density polyethylene weave lets air and water pass through while providing durable protection against sun damage and wear.
• Stainless steel D-rings: Rust-resistant D-rings at each corner make it simple to secure the sail and hold up better in wet conditions than plated hardware.
• Double webbing and reinforced seams: All edges are double layered and stitched to prevent fraying and extend the life of the sail under tension.
• UPF50 and 95% UV blockage: The fabric blocks up to 95% of harmful UV rays and can lower shaded temperatures by roughly 10 to 15 degrees, improving outdoor comfort.
• Water and air permeable: The sail is breathable so rain drains through instead of pooling, reducing the chance of sagging during storms.
• Custom size options: Multiple sizes and customization are available so buyers can match the sail to patios, carports, pools, or pergolas when measured carefully.

Who It's For

The ShadeMart 20' x 21' sail is ideal for homeowners with medium to large outdoor spaces who want dependable sun protection without trapping heat or water. It particularly suits RV owners, carport users and patio owners who need a breathable canopy that reduces temperatures and shields surfaces from UV fading.

Those seeking a fully waterproof cover or an exact off-the-shelf fit should look elsewhere; this style is intentionally water permeable and customers should measure carefully before ordering a custom size since dimensions are manually made and may vary slightly.

Pros & Cons

Pros

• Solid build quality with stainless steel D-rings and reinforced stitching that customers praise for durability.
• Excellent sun protection, blocking up to 95% of UV and noticeably cooling shaded areas.
• Breathable design prevents water pooling and remains effective in windy conditions when properly installed.
• Custom size options let you fit the sail to diverse applications like patios, pools or carports.

Cons

• Not waterproof - the fabric is designed to be water permeable, so it will not keep heavy rain fully out.
• Color can vary slightly and precise sizing relies on careful measurement, which some customers note as a limitation.

Specifications

Brand	ShadeMart
Shape	Rectangle
Size	20' x 21'
Material	Woven HDPE (High Density Polyethylene)
Hardware	Stainless steel D-rings with heavy duty white webbing
UV Protection	UPF50, blocks up to 95% UV
Water Resistance	Water permeable / breathable (not waterproof)

Our Verdict

The ShadeMart 20' x 21' rectangle shade sail is a practical, value-oriented choice for anyone who needs robust sun protection and airflow rather than a waterproof canopy. Its durable HDPE fabric, rust-free D-rings and reinforced edges make it a long-lasting solution for patios, carports and RV covers, provided buyers accept a breathable design and take care to measure their space before ordering.

Frequently Asked Questions

Is this sail waterproof?
The sail is water permeable and breathable, so it will not keep out heavy rain and is not intended as a waterproof cover.

Can I attach the sail to trees or poles?
Yes; with proper hardware kits it can be secured to poles, trees, walls or roofs for patios, pergolas and carports.

How much UV protection does it provide?
The fabric is rated UPF50 and blocks up to 95% of harmful UV rays, helping reduce shaded temperatures by about 10 to 15 degrees.