FlowGuard Slip Under Shingle 5 in & 6 in Gutter Cover System - Matte

Our review of the FlowGuard USA Made Slip Under Shingle gutter cover finds it best for homeowners who want a long-term, low-maintenance solution to clogged gutters. The single biggest reason to buy is durability: FlowGuard is fabricated from.018 heavy gauge painted aluminum and includes stainless steel fasteners so the system resists rust, severe weather, and seasonal debris buildup. For DIYers comfortable with basic metal cutting and a drill, FlowGuard promises a permanent, under-shingle installation that keeps heavy rain flowing and most leaves from entering gutters.

Key Features

• Made in the USA: Every panel and fastener is manufactured domestically, which supports consistent quality control and material standards.
• Heavy gauge aluminum: The.018 painted aluminum construction will not rust or deteriorate, extending service life and reducing future replacements.
• Under shingle permanent mount: The design installs under the shingle and secures with included stainless steel twin thread pierce point zip screws to withstand heavy rain, snow loads, and strong winds.
• 3-point airflow design: The raised three-point pattern elevates wet leaves to prevent sticking and lets wind and rain remove debris over time, keeping gutters clear.
• Easy, continuous installation: Dual interlocking ends and a 45 degree drain hole pattern make cutting, mitering, and joining runs straightforward with tin snips and a drill.
• Long warranty: Backed by a 50 year manufacturer warranty that offers confidence in long-term performance.

Who It's For

FlowGuard is aimed at homeowners with standard 5 in or 6 in gutters who want a durable, low-maintenance gutter guard that installs under the shingle and remains in place through severe weather. It suits DIYers with basic tools and experience cutting metal and driving screws, and those who value a product built from heavy gauge aluminum with stainless fasteners.

It is not ideal for people unwilling to lift shingles or perform roof-edge work, or for those who require a non-penetrating clip-on system; the FlowGuard installs permanently with provided fasteners and is intended as a long-term solution rather than a temporary or purely reversible option.

Pros & Cons

Pros

• Durable.018 heavy gauge painted aluminum resists rust and long-term degradation.
• Included stainless steel #8 twin thread pierce point zip screws make attachment secure in extreme weather.
• 3-point design prevents debris from sticking and allows heavy rain to flow freely into the gutter.
• Dual interlocking ends and simple cutting pattern speed up continuous installations and mitered corners.

Cons

• Requires under-shingle installation and basic roof-edge work, so it may not suit those who want a non-penetrating, tool-free option.
• Installation involves cutting metal and driving screws, which can be challenging for users without DIY experience.

Specifications

Material	.018 heavy gauge painted aluminum
Compatibility	Universal for 5 in and 6 in gutters
Length Included	102 ft total
Fasteners	Stainless steel 1/2 in #8 twin thread pierce point zip screws included
Design	Under shingle with 3-point airflow and 45 degree drain hole pattern
Colors Available	White, Thermal Thaw Black, Brown, Matte Aluminum
Warranty	50 year manufacturer warranty

Our Verdict

FlowGuard is a durable, well-engineered gutter cover for homeowners who want a permanent, low-maintenance solution that performs in heavy rain and wind. The heavy gauge aluminum, stainless fasteners, and 3-point design deliver long-term gutter cleanliness and good value for those comfortable with a DIY under-shingle install.

Frequently Asked Questions

Will this work with 5 in and 6 in gutters?
Yes, the product is universal for 5 in and 6 in gutters and ships as a 102 ft system sized for those common gutter widths.

Are the fasteners included rust resistant?
Yes, stainless steel 1/2 in #8 twin thread pierce point zip screws are included to prevent rust and secure the cover long term.

Can I cut and miter corners?
Yes, the FlowGuard is easily cut with tin snips and the 45 degree drain hole pattern simplifies cutting miter corners for continuous runs.