Renovation & Design

ASK THE INSPECTOR: Debris-catching products can be trouble

Eavestrough gutter guards can keep out leaves, but vary in effectiveness and ease of installation

QUESTION: I would appreciate your comments on a product named Gutter Stuff, which is available at Home Depot in Winnipeg. A friend of mine had suggested a product called "rain filter" which appears to be very similar to the above product and which he installed about four years ago without problem. Gutter Stuff is a foam-like substance and comes in four-foot lengths which are quite easy to install into the eavestroughs.

My concern is in the late fall when things start to freeze. Will any leftover moisture in the foam freeze and expand, splitting the eavestrough? The roof line is a cottage-style with eavestrough around the complete structure.

Your comments and suggestions would be most appreciated.

Don Olafson. Gimli

ANSWER: There have been numerous types of products developed over the years to help ease the difficult maintenance task of cleaning debris from eavestroughs. Many have failed miserably, either due to our difficult climatic conditions or poor design features.

I have similar reservations to yours about any product that goes inside the troughs, and some other concerns about reducing the effectiveness of roof drainage.

There are two basic types of products to prevent leaves and debris from entering and blocking proper eavestrough drainage. The style you cite is typically constructed of woven plastic mesh or foam, which compresses slightly and fits inside the trough by a combination of gravity and friction. The idea is that the gaps between the mesh or foam can allow water to drain through to the bottom of the gutter, while keeping debris on top.

While this may be quite effective in keeping large items like leaves and twigs from filling up the troughs, smaller debris can actually get caught in the mesh and plug up the drainage function.

It's true individual sections should be easily removable for cleaning with a garden hose, and then replaced, but this product also limits the amount of water that can enter the trough, possibly leading to overflowing during heavy rains or excess ice buildup in the shoulder seasons.

The second and more prevalent type of gutter guard installs over top of the gutters and is perforated. Some of these are plastic composites, but the better-quality ones are metallic.

The plastic styles often do not perform well over time, due to deterioration of the plastic from ultraviolet light and expansion and contraction. They also do not have enough strength to avoid bowing or buckling from the weight of debris or from eavestrough movement. While they can be installed quite easily by compression inside the top of the gutter and are easily removed for cleaning, they often require replacement every few years due to deterioration.

The metallic style of perforated "gutter guards" are often more durable than vinyl, but require more effort for installation and removal. These mostly flat devices are usually secured to the lip of the gutters with small sheet metal screws. The other end is designed to tuck under the overhanging sections of the roof and may have an integral soft plastic fin that helps to seal against water backing up under the shingles.

The benefit of these metal products are both the durability and strength. They will not only last for many years, but may actually help reinforce the eavestroughs, which can easily bend or warp if fasteners come loose. They may help prevent damage to thin, aluminium eavestroughs from hailstorms or ice buildup. The only drawback is the potential for easy blockage of the small surface holes by debris.

The interesting thing about any of these products is the idea that they are designed to minimize the chore of cleaning debris from eavestroughs. While they may all help to some degree, they do not eliminate the requirement for frequent cleaning. They may simply make the cleaning job easier than pulling out 10 centimetres of wet, soggy leaves and roofing granules with a wet glove or bare hand. They still require elimination of surface debris, but it may be possible to complete the job with a stiff broom or garden-hose nozzle.

To test the effectiveness of the metallic style of gutter guard, I graciously accepted an offer from local roofing specialists Dr. Roof, who have done previous installations and repairs on my home, for a partial installation. They installed their preferred brand on one side of my home, where I have excessive debris issues from nearby pine trees. The idea was to compare that side of my eavestroughs relative to the rest, in relation to cleaning and maintenance.

After a recent deluge caused many areas of my gutters to overflow, I inspected and cleaned the entire system. I discovered that part of the reason for the overburdened troughs was excessive pine needles, cones and shingle granules blocking the gutter openings, above the tops of several downspouts.

The storm did not appear to have the same overflowing effect on the protected side, but a large amount of debris still required to be cleaned off to the top of the leaf protection afterward. I suspect that drainage was also worse in the non-protected side due to blockage where debris prevented proper water flow under the metal cover on that side, which would not occur if I had a complete installation.

To summarize, and answer your question more directly, the effectiveness of any product designed to prevent excessive debris from filling up your eavestroughs may only be determined after prolonged use. I would avoid anything that reduces the water-carrying capacity of the system, like the "Gutter Stuff" you have mentioned, but rigid metal systems that install over top of the existing eavestroughs may be relatively effective.

Regardless, even with a quality product installed, regular cleaning and maintenance is necessary to allow proper roof drainage.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors - Manitoba ( Questions can be e-mailed to the address below. Ari can be reached at 204-291-5358 or check out his website at


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