Gotta Get a Gutter

But are all gutter systems equal in the eyes of this ASHI Inspector?

Because in North America it rains either occasionally or all the time, water management is a consideration for all property owners. For every inch of rain that falls on a square foot of a flat roof, there’s .625 of a gallon of water to be managed. That translates to 1,250 gallons of water for every inch of rain that falls on a 2,000 square foot flat roof. The relationship changes with the pitch of the roof, but the basic idea remains the same: there’s a lot of water to be managed when it rains.

As a home inspector, I’ve seen the problems caused by poor water management: decayed siding and paint failure with accompanying mold and insect intrusion, as well as water in the basement or crawlspace. None of this is healthy for the occupants or the building. Home inspectors who fail to recognize and report water management issues are sure to find themselves with unhappy clients.

In my region of the country, gutter systems are used to help manage water. Over the years, I’ve seen a variety of gutters and, based on my observations, have developed some opinions on their effectiveness.

The Yankee Barn gutter: Essentially, two pieces of wood fabricated into a “V”; the ones I see have open ends. Water spilling out the ends decays the corner posts of the wood-framed structure and leads to rising damp, mortar degradation and efflorescence of the masonry.

Integral gutter: I see these frequently on Victorian buildings. Often, a roofer has covered them with roof shingles and flashing. I’ve watched integral gutters work during a fair-sized rainstorm. Usually, they overflow, spilling water down the face of the building. It has been my experience that in anything more than a light shower, they will under-perform; in other words, fail to collect the water and deposit it away from the building.

Wooden gutters: These have been around for quite some time. Most have a 31/2-inch wide trough and a shallow depth. They require a boiled linseed oil application at least twice a year. I’ve found that the older the wooden gutters are, the more likely I’ll find interior tarred joints, oversized lead patches, and seriously decayed fascia and soffits. Another problem for homeowners is the required regular maintenance, especially if the wood is not a decay-resistant species. Can you picture your client swinging from a ladder trying to apply boiled linseed oil to the gutters? Even well-maintained wooden gutters almost always are undersized, and the 11/2-inch discharge ports frequently plug up. Water cascading down the side of the house, causing windows and trim to decay, and finding its way to the basement or crawl space is not a pretty picture.

Copper, vinyl, aluminum and galvanized steel also are used for gutters. There are pros and cons for each material (see illustration). Regardless of the material, a correctly installed and sized gutter sys-tem should collect all of the water and discharge it at least 6 feet away from the building, assuming that the grading is correctly sloped.

I have found that when the gutter is spaced off the fascia board about one inch, it will collect all of the water. Based on my experience, the various gutter deflectors are not effective in regions where there is an abundance of small leaves or Pine tree needles. These clog the louvers, rendering the gutters useless. The gutters still need to be cleaned on a regular basis.

Downspouts are as important as any other part of the gutter system. When a gutter system is working efficiently, it collects water and carries it away from the house. The preferred number of downspouts differs from region to region. While one downspout for every 35 feet of gutter is the rule of thumb, in the Northeast one every 40 feet is the minimum.

Because I inspect homes in the Northeast, where it rains hard and frequently, often I find it necessary to suggest to buyers that increasing the number of downspouts on a house would be beneficial and potentially reduce the maintenance costs for the structure.

Having established that there are many types of gutter systems, and that they are an important element in any water management system, it’s obvious that there’s a lot more to learn about them. Some factors are as simple as attachment systems; others are as complex as evaluating an appropriate system for a house with one or more secondary roofs. To learn more about gutter systems, visit the following Web sites:

An installation manual with tables of Rainfall Data and Drainage Factors by state and cities within the states, and of Area Factor in Pitched Roofs; and sections on Hung Gutters and Downspout Basics, Downspouts, Downspout Hangers and more can be found at
www.copper.org/applications/architecture/arch_dhb/gd/gd_intr.html

For more on sizing gutter systems, visit 
www.taunton.com/finehomebuilding/pages/h00046.asp

Information on how to maintain gutter systems — or choose and install new
systems is detailed at www.oldhouseweb.com/stories/Detailed/10162.shtml