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.)