Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER ENTRY IN BUILDINGS
AGE of MOLD, HOW OLD
BASEMENT CEILING VAPOR BARRIER
BASEMENT MOLD WATER IMPACT
BRICK WALL DRAINAGE WEEP HOLES
BUCKLED FOUNDATIONS due to INSULATION?
BUILDING DAMAGE ASSESSMENT & REPAIR
CONDENSATION on WINDOWS & SKYLIGHTS
DEW POINT TABLE - CONDENSATION POINT GUIDE
EFFLORESCENCE SALTS & WHITE DEPOSITS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOD DAMAGED FOUNDATIONS
FLOOD VENTS & FLOOD PORTS
FLOODS IN BUILDINGS-mold
FLOOR DAMAGE DIAGNOSIS
FOOTING & FOUNDATION DRAINS
FOUNDATION BULGE or LEAN MEASUREMENTS
FOUNDATION CRACKS & DAMAGE GUIDE
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB
GOPHER HOLE DAMAGE
HUMIDITY LEVEL TARGET
ROOF ICE DAM LEAKS
MOISTURE CONTROL in BUILDINGS
MOLD INFORMATION CENTER
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
SEWAGE BACKUP, WHAT TO DO
SEWAGE BACKUP TEST & CLEANUP
SEWAGE BACKUP PREVENTION
SEWAGE PUMP CLOG DAMAGE
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
SWEATING (CONDENSATION) on PIPES, TANKS
TOILETS, INSPECT, INSTALL, REPAIR
TRAPS on PLUMBING FIXTURES
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WATER ENTRY in BUILDINGS
WINTERIZE A BUILDING
This article describes the common sources of foundation leaks and wet basement and how to find and fix them: sources of water outside and around buildings such as roof spillage, surface runoff, groundwater, mishandling of roof gutters and downspouts, and improper exterior foundation drains or footing drains.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
Our page top sketch of swale drainage construction is provided courtesy of Carson Dunlop Associates.
[Click to enlarge any image]
Roof Gutters, Downspouts, & Leaders: the most common source of foundation leaks and wet basements
Roof gutters and downspouts - check to see that roof runoff is effectively disposed of away from the building, and that it is actually working.
Most of the wet basements that we (DJF) have investigated were suffering from mishandling of roof drainage. Between gutter defects that spill large volumes of water close to the foundation and improper site grading, we estimate that 80 percent or more of basement water entry problems can be explained.
Do not tie the downspouts into the footing drains - you will simply overload the footing drain system and risk future basement water entry. We want to see gutters extended to release roof drainage no less than 10 feet from the home, more is better, and even more important, from the point at which water leaves the downspout end, it should continue to flow away from the building, not back towards it.
Add a splashblock to route surface runoff around a chimney whose side formed a water trap against the foundation wall
Improper Site Grading, In-Slope Grade May Send Roof Spillage or Surface Runoff into Building Basements or Crawl Areas
Site grading and control of surface runoff - see Finish Grading.
Keep water away from the foundation.
As we detailed at BASEMENT WATER ENTRY PREVENTION, this means proper site drainage that assures that surface runoff and roof spillage are conducted away from the building.
Our photo (above left) shows a home with an in-slope grade facing the house wall. It would have been relatively easy to install a swale draining hillside water and roof spillage around the left side of the home in this picture.
Instead the owners suffered decades of wet basements until the wet conditions made the home sills so attractive to termites that major
At grade, the main object is to get water away from the foundation as quickly as possible. Finish grade should slope away from the building for at least 10 to 15 feet, and should not contain low spots that will make water ponds.
Swales: if one or more sides of the building face an upwards sloping hill, slope the finish grade away from the building for at least 10-15 feet, and then shape the finish grade at that point into a swale that itself continues to carry water around to the downhill side of the building.
Details about proper surface grading to control runoff are found at SURFACE CONTOURING for DRAINAGE
Foundation ditches: Do not do what we have found at some flooding basements: an in-slope grade problem that was trapping surface and roof runoff against the house was "fixed" by digging a ditch right against the foundation wall in an attempt to carry water away. The ditch digger simply had built a water trap to guarantee that water would be sent against the foundation wall.
Guide to Foundation Drainage Details to Avoid Foundation Leaks & Wet Basements
Footing drains / foundation drains - check for presence of and check that water is flowing out of footing drains if water is in the basement. If the basement is wet and the footing drains are dry, they are not working.
Our photo (left) illustrates a foundation drain that is "brought to daylight" at a property.
But this foundation drain (or "footing drain" extension) raises some questions: the use of perforated pipe far from the building may be ok.
And it's proper to use perforated pipes around the foundation footings themselves, so that water can enter the drainage system for disposal.
But if the pipes carrying this drainage "away" from the building are in fact perforated and are leaking it back into soils close to the structure, we may be simply recycling water rather than disposing of it.
Other Outdoor Sources of Basement Leakage & Water Entry
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
This article series discusses methods for preventing wet basements by attention to multiple best construction practices, including the basics of foundation d & roofing, poor site drainage, bentonite clay for basement waterproofing, foundation membranes to prevent leakage, foundation drain tiles, proper backfill, and proper finish grading.
Continue reading at GRADING, DRAINAGE & SITE WORK
or see GUTTERS & DOWNSPOUTS
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Questions & answers or comments about troubleshooting wet basements: finding outside sources of water leakage.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References