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Roof gutter defects & how they cause building leaks, damage, or wet basements & crawl spaces. Here we list and describe gutter problems and defects including clogged gutters, leaky roof gutters, overflowing gutters, sagging, loose, poorly-sloped or damaged gutters and other roof drainage system problems.
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The two most common building leaks that cause wet basements or crawl areas originate at the roof drainage system:
If you see shrubs growing in your gutters (below left) you know the roof drainage system has not been cleaned in a long time - look for basement water entry, building wall damage or rot, and related water problems. Inspecting from a ladder you may also find that even a small handful of leaves and crud can block the downspout connection (also called an "end drop") leading to gutter overflowing and building water entry (below right).
Take a look around your building for gutters that are actually falling off (or have already fallen off - below left) but also look for loose gutter spikes or brackets (below right).
Loose gutters, before they have fallen away from the building, are permitting roof runoff to miss the gutter and run down building walls, enter soffits or eaves (rot), and by falling close to the building foundation wall, the water concentrating there is likely to enter the building basement or crawl area.
Try looking "up" from below the building's gutter system (photo below left). If you see daylight between the back side of the building gutter and the fascia board, check further for gutter backflow, leaks, or simply a gutter that has begun to pull away from the building.
A second easy-to-spot loose gutter warning is the gutter spikes projecting out from the gutter edge (below right).
Watch out: Don't forget to inspect the gutters closely from the roof edge as well. A loose gutter may be out past the shingle edge or drip edge but may not be visible from the ground. When it rains, water runs down the building wall at this point.
Improperly-sloped gutters will not empty properly and in heavy rain are likely to overflow.
Check that the roof gutters are properly sloped, both in the pitch and in the direction of pitch towards the gutter drains or downspouts.
Our photo (left) shows a desperate attempt to get back proper slope and drainage in a long gutter run that had sagged at its center.
On long gutter runs attached to a roof with a rather short fascia board, it can be difficult to obtain adequate slope.
Roof gutters should slope at least 1-inch in every 200 inches of run; also see SAGGING GUTTERS since even if the gutters were originally installed with proper slope they may have sagged due to loading from clogs, water, ice or debris.
But if the total length of the gutter run is long and the fascia is not very tall, say 6 to 8", then it may be impossible to get adequate gutter slope throughout its total run, even if we push the high end of the gutter right up against the shingle overhang and drop the low end of the gutter to the very bottom of the fascia. If your roof has this problem it may be necessary to add additional downspouts along the gutter's run and/or to divide the total gutter run into shorter lengths.
Then re-start gutter sections higher on the fascia.
Some causes of improper gutter slope include:
Gutter Mounting Position Affects Gutter Performance & Resistance to Snow & Ice Damage
The sketch at left shows optimum gutter placement at the building eaves to catch water spilling off of the roof. As you can see, the gutter location depends in part on roof pitch.
Proper gutter placement is especially important in freezing climates in order to reduce the tendency of snow and ice to "push" the gutters off of the building.
Gutter overshoot refers to water that runs down the roof and over or past the roof gutters rather than into them. Some common causes of gutter overshoot include:
The sketch at left shows what happens when roof shingles extend too far past the edge of the roof deck and too far into the roof gutter.
The sketch does not show what happens if the roof shingle projection past the roof deck is not supported by drip edge: with time the roof shingles curl down into the gutter itself, and sometimes crack or even break off at that point.
Sketch courtesy of Carson Dunlop Associates.
Install a Gutter Defelector to Cure Gutter or Roof Valley Runoff Overshooting the Gutters
Our roof gutter deflector photos (above) show a deflector installed at the end of a roof valley (above left) and at a different home, evidence of spillage and splash-up below a roof valley due to gutter overshoot (above right).
Take a closer look at the gutters in our photo at left where a valley spillage gutter deflector is installed: notice all those mineral granules.
This roof had been damaged by hail. Our OPINION was that the extra loss of mineral granules meant that the roof would probably have a shorter remaining life than usual.
Here is another closeup photo of a gutter deflector installed below a roof valley.
Continue reading at GUTTER DEFECTS, MORE
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