Are Gutters & Downspouts Required?

Specific Inspection Topics Roofing Inspections
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What does a home inspector report when there are no gutters and downspouts installed on a house?

It’s interesting because gutters and downspouts are infrequently mentioned in the International Residential Code (IRC). Code is fairly silent about their actual presence, function, or installation requirements. However, there are a couple resources in the 2018 IRC that we value referencing, including the code commentary provided by IRC:

R903.4 Roof drainage.
Unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof.

❖ IRC Code Commentary: In most residential construction, drainage water from the roof simply flows down the roof’s slope and over the roof edge, often to a gutter and downspout system that carries the water away from the building. In situations where the roof design does not allow for water flow over the roof edges, roof drains must be installed in the roof surface. The drains will be at the low points of the roof, sized and located to remove all roof water. In a case where the low points occur at parapets of the exterior walls, scuppers through the parapets must be provided, constructed with the flow points level with the roof surface at the low points and located based on the roof slope and contributing roof area.

2018 International Residential Code and Commentary, Volume 1 and 2 | Chapter 9: | R903.4 at https://codes.iccsafe.org/content/IRCComm2018/chapter-9-roof-assemblies

P2912.5 Roof gutters and downspouts.
Gutters and downspouts shall be constructed of materials that are compatible with the collection surface and the rainwater quality for the desired end use. Joints shall be water tight.

❖ IRC Code Commentary: The materials of construction of gutters and downspouts must be “compatible” with the raw rainwater quality that is needed for the end uses. The intent is the same as for roof materials that collect rainwater. As gutters are often in direct contact with roofing materials (the collection surface), material compatibility between the two surfaces must be considered. For example, an aluminum collection surface (roofing) might not be compatible with galvanized steel gutters.

2018 International Residential Code and Commentary, Volume 1 and 2 | Chapter 9: | R903.4 at https://codes.iccsafe.org/content/IRCComm2018/chapter-29-water-supply-and-distribution

Here are a couple of inspection tips related to gutters and downspouts:

The InterNACHI Home Inspection Standards of Practice require the inspector to inspect gutters and downspouts (https://www.nachi.org/sop.htm#roof).

If gutters and downspouts are NOT installed, and the roof water runs directly off the roof and onto the ground, and the surface drainage and grading of the property may be adversely affecting the structure due to moisture intrusion (https://www.nachi.org/sop.htm#exterior at 3.2.I.J), the inspector may make the observation and recommendation to correct the defect, especially if there are observed indications of water intrusion into the building (https://www.nachi.org/sop.htm#basement at 3.3.III.B.)

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Now, how about the “rest of the story”… WINTER!!!
Ain’t no water running off of roofs in Minnesota and other Northern areas during Nov-Dec-Jan-Feb!! (Typically).
ice dams

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R903.4 would typically be a flat roof with parapets or a really funky built sloped roof with dead valleys.

P2912.5 deals with “NONPOTABLE RAINWATER COLLECTION
AND DISTRIBUTION SYSTEMS” which is not applicable to a typical home.

For our area much of the soils are highly expansive and gutters are covered under R801.3.

R801.3 Roof drainage. In areas where expansive soils or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface not less than 5 feet (1524 mm) from foundation walls or to an approved drainage system.

Beyond that if you are using just the Codes as a source there are no other “requirements” for gutters. Of course there is a common sense requirement for them on just about any home.

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IRC Section R801.3 ROOF DRAINAGE

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In Oregon they’re not required. Oregon Residential Code R 903.4 - That said, they’re necessary on the west side of the Cascades (temperate rain forest) where most of the population is located. I was always calling out defects in drainage when I lived there.

Where I now live on the east side of the mountains (high desert) they’re much less common, and some winters, can lead to ice dams. Most new construction by mid-to- higher end builders now incorporates gutters along with better air sealing and insulation than much of the older stock of housing.

R903.4 Roof Drainage

Unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof.

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Yep… … …

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Here in the Texas Hill Country there are many lots with plenty of slope to take water away from the home. Gutters would simply be personal preference in these situations & I make no mention or recommendation for them.
Just the same, there are lots that are not as well drained & can greatly benefit from them.

When I feel they are necessary for drainage or foundation performance, I recommend as follows:

  • Gutters recommended (supplemental)

  • IMPACT- The property grading alone, or certain areas, may not be sufficient at shedding the large concentration of roof water away from the home in a timely fashion which may have adverse effect on the foundation considering our local expansive soil. A gutter system can aid by collecting and discharging the roof water away from the foundation.

  • SUGGESTIONS- Installing a gutter system around the entire home or that portion needing assistance is recommended.

Sometimes gutters are needed for reasons other than foundation performance such as damage to siding when falling roof water splashes off an adjacent patio.

  • Gutters recommended (splashing)

  • IMPACT- Roof water discharge onto the concrete flat work appears to be backsplashing onto the home causing damage & premature wear.

  • SUGESTION- Gutters are recommended at appropriate locations to prevent excessive wear of exterior building components.

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Welcome to Phoenix where gutters are a rarity. The three time it rains in a year, we just put up with it.

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I’m in Anchorage, Alaska and I call it out every time i see them missing. Between the rain and snow here for 8 months out of the year you bet missing roof drainage is missing I’m calling it out.

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I definitely note them in my reports:

The Inspector observed one or more area(s) with missing gutter(s) and/or downspout(s). Gutters and downspouts function to channel and control precipitation run-off from the roof surfaces to prevent direct drainage against the foundation. Additionally, the allow for comfort in keeping the structure approachable during rain, etc. and not having it drip onto persons. We recommend having a qualified professional add the missing gutter(s) and/or downspout(s) for your convenience and to protect the structure’s foundation.

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I just ask my clients if they hate money.

Yes?

then pop a natty light, kick back, and watch your new dream home get wrecked. Those contractors will be happy to relieve you of your accursed dollars

or you could get gutters.

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They are not required around here.