InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
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.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Common Gutter Defects & Causes of Leakage & Wet Basements / Crawl Spaces
The two most common building leaks that cause wet basements or crawl areas originate at the roof drainage system:
Gutter defects: Clogged, overflowing gutters; also gutters that are falling off, improperly sloped, or leaky - discussed here at GUTTER DEFECTS LIST
Downspout defects: Downspouts that are emptying too close to the building; also downspouts or "leaders" that have been disconnected or were improperly connected . Downspout defects are detailed at Roof Downspout or Leader Defects.
Roof Gutter Defects List
Our list of common gutter defects shown just below is followed by illustrations or photographs of many of these conditions.
Backflowing gutters: water falling off the roof edge runs behind the gutter or between the gutter and the building fascia rather than falling into the gutter.
Clogged gutters lead to overflows, water spillage around the building, water entry, as well as gutter damage. G
utter screens and shields may be installed to reduce the frequency of gutter cleaning, but these components are by no means a magic bullet nor a substitute for regular gutter inspection and cleaning, and if not properly installed they make gutter cleaning more difficult.
Loose gutters, failing hangers, falling off, or sagging; insufficient number of gutter supports or hangers; as gutters pull away from the building roof drainage runs behind the gutter, spilling by the building.
Gutter Painting needed: galvanized steel gutters and downspouts need to be kept painted to resist corrosion and leakage. Painting the gutter interior surface and using moisture-resistant paints may extend the gutter life.
Gutter sagging: gutters that are sagging or lack slope towards the downspouts will drain too slowly and become heavy with water and debris, leading to loose or falling gutters as well.
If you see shrubs growing in your gutters (below) 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).
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.
Inadequate or Improper Gutter Slope
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:
Improper original installation: gutters installed "flat" or sloping away from the downspout drain
Improper original installation: gutters lacked adequate number of supports or hangers to prevent sagging. See GUTTER HANGERS and also see SAGGING GUTTERS.
Gutter slope changed due to gutter movement from
Damage - falling limbs, ladders, work on roof
Weight of water from clogged gutters
Weight of snow or ice in gutters
Pushing or movement of gutter caused by ice or snow
Gutter "Overshoot" - Water Flows Over or Past Rather Than Into Roof Gutters
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 from Too Much Shingle Overhang at the roof Eaves
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:
Excessive roof shingle overhang (illustrated below). This roofing installation error not only interferes with good gutter operation, it also risks breakage along the roof shingle edges.
It's easy to fix this mistake: be sure that roof drip edge as been installed to support the extension of shingle beyond the very edge of the roof deck, then trim the shingles so that no more than 1/2" of shingle material extends past the edge of the drip edge itself.
The sketch above 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.
Roof Valley Overshoot: gutters too small in width for volume of roof runoff; this problem is most frequent below roof valleys where a higher volume of water may be running down-roof in heavy rains.
If your building design includes inside corners of abutting roof slopes, inspect the ground below the valley for evidence of roof valley overshoot (you'll see an area of soil washed away, siding or wall damage from rain splash-up, or building water entry in the basement or crawl space at this location. Spilling water from a roof valley into an inside building corner also tends to increase water entry because the angled foundation walls tend to form a water trap at that location.
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.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: firstname.lastname@example.org
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Certainteed Weatherboard fiber cement siding and trim products - see certainteed.com/ or see certainteed.com/resources/sidingandtrimspecsheet.pdf
"Flashing: the plain solution to leaky walls", Thomas E. Remmele, Manager, Technical Services, Sto Corporation, Building Standards, November/December 1999 p. 21-25.
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones