The Six Types of Gutter Guard, and What Each One Actually Does

Brush inserts

A long cylindrical brush that sits down inside the trough, bristles up. Leaves land on the bristles and, in theory, blow off; water runs through underneath.

It is the simplest system there is. The weakness is that the brush becomes the debris: needles and small seeds work into the bristles and stay there, and eventually you are pulling the brush out to clean it rather than cleaning the trough. On a house with spruce over the roof, brush disappoints soonest.

Foam inserts

A wedge of open-cell foam that fills the trough. Water passes through the foam; debris rides on top.

Same appeal as brush, and a similar limitation. Foam holds grit and holds moisture along with it, and in a climate that freezes and thaws repeatedly through one winter, a saturated foam wedge in a trough is not doing you a favour. Seeds also germinate in it, which sounds like a joke until you see maple seedlings along somebody’s roofline.

Solid covers

A rigid cover, aluminum or PVC, that closes the top of the trough and admits water through perforations or slots. The version with small punched holes across an aluminum face is the most common “standard” guard in Canada.

Solid aluminum covers handle this climate well: aluminum does not go brittle in cold the way PVC can, and a rigid cover carries wet snow without deforming. The variable to ask about is perforation size — large enough to move water quickly in a downpour, small enough that needles and granules do not simply pour in. Those two goals pull against each other, which is why perforation patterns differ so much between products.

Coarse mesh screens

A screen with visible openings, laid into or clipped over the trough, usually aluminum or steel.

Mesh screens stop leaves reliably and cost less than fine-mesh systems. What they do not stop is anything smaller than the openings — spruce needles, maple keys, and the granules every asphalt roof sheds as it ages. On a lot with deciduous trees only, a coarse screen is often the sensible answer. Under conifers, a partial one.

Micro-mesh

A fine stainless or aluminum mesh, usually stretched over a rigid frame, with openings small enough to exclude needles and shingle granules.

This is the type most often confused with the one above, and the distinction is the most important on this list: micro-mesh is the only construction that reliably keeps fine debris out of the trough. The trade-offs are cost, and that the mesh itself needs occasional attention — pollen, dust and fine grit build into a film on the fabric, and water then runs over the mesh instead of through it. Being told a micro-mesh system will never need touching is a claim to be sceptical about.

Reverse-curve

Also sold as surface-tension systems, and referred to colloquially as helmets. A curved nose closes the trough, water clings to the curve and follows it around into a narrow slot, and debris carries on past the edge and falls to the ground.

It works on real physics and it handles leaves very well. The considerations: the curve is visible from the ground and changes the look of the roof edge, heavy wind-driven rain can overshoot the slot, and the same narrow slot that admits water can be blocked by fine grit over time. It is also the type most dependent on installation angle — fitted a few degrees off, the effect it relies on stops working.