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This article was published 24/5/2013 (1372 days ago), so information in it may no longer be current.
QUESTION: I have a problem with water dripping from my eavestroughs at the end joint and at a 90-degree connection. The drops of water fall on my steps and freeze, causing a safety problem. I sprayed both places with auto undercoating in the fall, but this had little effect. I thought that since this coating could withstand the abuse of being on the underside of a car, it would solve the problem.
Since it didn't work as I expected, can you suggest something else that might work. Thanks very much for your attention to this, Arnie Slotin.
ANSWER: While it may seem like this is a minor issue, water management outside your home is critical to prevent both exterior damage and moisture intrusion and damage inside. The eavestrough system is critical to this water management, and any leaks should be repaired as soon possible.
Leaks in eavestroughs at the corners and ends are due to either deterioration in the materials themselves, or sealants used to waterproof these junctions. Deterioration normally only happens with older galvanized steel systems. While they were used successfully for decades, with very good durability, they've likely exceeded their normal life expectancy if they are still on your home. Pinhole leaks caused by corrosion can occur anywhere in the troughs.
It's more likely that the soldered ends or corners have worn out and opened up in your eavestrough. If this is your situation, a total upgrade is in order, as sealing this older material rarely works.
When older troughs and downspouts are upgraded, the most common material used is pre-finished aluminum. It's the preferred choice because of its excellent resistance to corrosion and permanent paint finish, which is available in multiple colours. It can be purchased at local building centres in three-metre lengths, which can be cut and joined together to fit your home. Joiners, end caps and corners are normally used with this style of eavestrough, which makes sealing easier and reinforces weak junctions.
A superior option is continuous aluminum eavestrough. These are better because they can be installed without seams and often are joined only at the corners. The troughs are produced from long rolls of pre-finished aluminium sheathing, which are formed after running through equipment specially designed to bend the thin metal to the desired shape. Because of the specialized equipment required, a truck with ladders, rollers and generator is normally needed. That's why this material is normally only measured and installed on-site by professional exterior contractors.
Whether you have sectional or continuous aluminum troughs, the corners, downspout drops and end caps must be sealed to prevent leakage. These joints are created simply by overlapping or crimping the thin metal, so they must be waterproofed. Various types of caulking are used, easily applied with a typical caulking gun. Additional sealant may be installed on the inside of these junctions for better coverage, but care must be taken not to impede proper water flow.
The types of caulking available for exterior household use are almost infinite, but each usually has a preferred application. Normal silicone sealant A common product used for eavestroughs is nIt is preferred by some installers due to its properties of excellent fluidity and water resistance. Even in cold weather, it can often be applied easily and in thin layers which prevent blockage of water flow inside the troughs.
This material may last for several years but will eventually wear out, causing leakage. While silicone caulking has many excellent properties for sealing various components, it's not very resistant to ultraviolet (UV) rays. Sunlight will cause deterioration over time, which will cause the material to deteriorate and lose it adhesion. If used in an interior application, such as a kitchen or bathroom, that should not be an issue. But on the inside of a metal eavestrough, which has a horizontal surface constantly exposed to sunlight, it won't last.
The solution to your dilemma, if you have aluminum troughs, is to remove any deteriorated sealant at the problem areas with a knife or scraper and replace it with a better-quality product. Using caulking that is waterproof, has good adhesive properties and is resistant to UV should do the trick. This should be available at local building centres or suppliers.
You are absolutely correct in attempting to stop the dripping from your eavestroughs, not only to prevent slipping on the steps below, but also to prevent potential moisture intrusion and damage to your home.
Quick-fix sealants, like the stuff you tried, rarely work. Cleaning the old sealant from your aluminum troughs and replacing it with professional-quality caulking is the right way to go. But if you do happen to have an older galvanized system, upgrading to aluminum may be your only option to stop the leaks.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors-Manitoba (www.cahpi.mb.ca). Questions can be e-mailed to the address below. Ari can be reached at (204) 291-5358 or check out his website at www.trainedeye.ca.