Exterior Water Management

For the newer inspectors there may be some confusion on the need for exterior water management when reading posts in this section. First, for all practical purposes all concrete foundations will crack, but not all cracked foundations will leak. Explaining all the reasons why concrete foundations crack is reserved for another topic, I am limiting this post to exterior water management only. Something else to keep in mind as we discuss this topic is foundations have two basic functions:

  • Transfer the house loads to the soil, typically through a footing.
  • Retain exterior soil.

To simplify lets group concrete foundations (crawlspace & basements) into two groups; ones that leak and ones that do not. Let’s start with foundations that leak. In order for a foundation to leak we obviously need two things; an exterior source of water and an avenue for water to enter the basement or crawlspace. Water typically enters in one or more of the following ways:

  • Over the top of the foundation wall.
  • Through openings such as a foundation vents, windows and doors.
  • Through wall cracks, utility holes, form-tie holes, construction joints, including the joint between the wall and the footing.
  • Under the footing.

Exterior water sources can be grouped in four basic categories:

  • Natural surface flow from rain water.
  • Natural subsurface flow from ground water.
  • Permanent or seasonally high water tables.
  • Man induced water leaks from broken pipes, irrigation systems, leaking swimming pools, etc.

Methods used to stop a water leak will vary depending on how accurate you are at identifying the water source and the path the water enters the basement or crawlspace. From these two lists you can see there are a large number of combinations when you consider the possibility of multiple water sources and multiple ways water can enter a basement or crawlspace.
Keep in mind if you are successful at stopping water from entering the basement or crawlspace you may have only treated the symptom to a larger problem. Remember the two basic functions of a foundation have to be preserved in order for the foundation to work. Here are a few examples:
Example 1: Surface water enters a crawlspace through the foundation vents.

  • Solution A: Intercept the water before it reaches the foundation with the use of a swale or berm and redirect around the foundation.
  • Solution B: Raise the grade at the foundation and use a window well to protect the foundation vents, if necessary.

**Discussion: **In this example if your solution eliminated surface water from entering the crawlspace vents AND the two basic functions of the foundation were preserved, then you have solved the problem. In this case and all following examples other solutions are only limited by experience and creativity.
Example 2: Subsurface water enters through a crack in the basement wall, i.e. the surface grading and gutter management were good.

  • Solution: Excavate and repair the crack, install external waterproofing and improve the perimeter drain tile system if necessary.

Discussion: In this example the solution eliminated subsurface water from entering the basement, however one or both of the two basic functions of the foundation maybe compromised. If subsurface water is reaching the exterior foundation wall the soil under the footing may become saturated. Saturated soil has less load carrying capacity, which can result in settlement problems. Second saturated soil next to the foundation wall is much heavier and increases the horizontal wall load, which can result in wall shoving. In this case the solution was incomplete. Intercepting the subsurface water flow may require the installation of a curtain drain or some other method of preventing subsurface water from reaching the foundation wall.
Example 3: Water enters under the footing into the basement, i.e. the surface grading and gutter management were good.

  • Solution: The solution will require more information such as:

o Is the water leaking in around the entire perimeter of the basement?
o Does the ground surface appear saturated?
o What is the soil profile?
o Is this a recent event or an ongoing problem?
o Has the water usage increased, indicating a water line leak?
o The list goes on depending on visual clues and possibly test results such as soil borings.
Discussion: In this example the solution requires determining the exterior water source. In some cases like this the cost to determine the water source may be cost prohibitive or it may be as simple as the basement was built in a swampy area with poorly drained soils. You just can’t fix stupid sometimes.
In closing I want to mention the obvious, even if a basement doesn’t have a leak, exterior water management is still required to preserve the two basic functions of a foundation, unless you live in a desert.

How are you doing Mr. Mayo :wink:

Correct me if i have it wrong but i do believe Mr. Mayo is saying, at least in part that it is very important to FIRST identify/determine the water source/path of how-where-why water gets into basement and crawls.

How ‘good’ one truly is starts with how experienced one is AND, in this crooked business, how honest one is to homeowners!!

In part what I mean is that those who ONLY install interior basement systems or much prefer to install interior systems is they have an AGENDA obviously. These companies pocket much more MONEY by installing interior systems because they are ALOT LESS materials involved and a lot less labor involved, hence the company pockets more cash.

Their agenda includes knocking exterior waterproofing, scaring homeowners from getting exterior waterproofing, lying about it, because… they don’t ‘do’ exterior waterproofing, they’ll LOSE business or again, they don’t want to do it as they know they’ll make less money and there is much more work involved (especially when hand dug).Their labor force can’t/won’t hand dig!

Randy is right on that water enters basements and crawls through…
-exterior openings ABOVE ground level, above the foundation wall
-cracks and others openings IN the foundation wall
-from underneath, under the FLOOR

So again, an experienced and honest HI or contractor SHOULD, first, be determining HOW and WHERE the water is getting in the basement/crawlspace… this is number 1, period, and interior basement system companies could care less about where that water is truly first entering.

If the leaky basement is finished then sometimes, it’s going to take MORE TIME to correctly and honestly identify the actual problem(s).
If an HI or contractor doesn’t have the time, the patience or the knowledge then, leave shtt alone, don’t open your pie hole and tell the homeowner to raise and slope the grade or, install an interior system, that is bs.

Shtt, i never go to anyone’s home, leaky basement and NOT identify their problem and instead, tell them they need exterior waterproofing. That would be the same crap as these inside system companies always do or some HI’s do.
Yep, sometimes one needs to explain and tell the homeowner they need to/would be best for them to, remove some of the drywall/paneling in order to help identify the dang problem(s).
In this short video B Dry previously installed an inside basement system…
When Basement Waterproofing Goes Wrong

The water was, and STILL is entering the basement through exterior cracks/cracked or no parging on exterior walls and possibly through 1+ openings ABOVE grade so installing ANY interior system and sump pump will not, will never STOP the water from WHERE it is entering! And as you can see, this garbage won’t stop-prevent mold

The guy/company that took the video is basically another interior system company.
So what do they do? Instead of doing the right-thing, exterior waterproofing, they rip out the B Dry junk and install another interior system!! loolololl

He actually states in the video that, part or all of the problem is B Dry covered the WEEP HOLES in lower blocks and water couldn’t get out.

Say again, the water is FIRST getting into the blocks/wall on the exterior!
So installing ANY interior system will NOT ‘stop’ firther water from getting into the blocks, helllllllo!
It is NOT that the dumb weep holes were covered with that plastic-board, jesus please help these people.

The mold is there because nobody stopped the water from where it’s entering.

The video is one of many that have been posted that shows/proves many in this business do NOT identify/determine the ACTUAL PROBLEM(s), due to dishonesty or incompetence!!

Short video on a previously installed interior basement system and sump pumps and then the wall bowed in, cracks widened

Again, these bubbleheads did NOT determine/identify the existing problems on WHY the cracks in wall originally occurred and what can/could happen in the future when one doesn’t relieve, reduce exterior weight/pressures against a wall and WHERE the water was getting into the blocks

To follow up Mr. Mayo’s thoughts on exterior water management, here’s a GOOD article on, Why Foundations Fail
In part it says, ‘The water pressure against a basement wall when the SOIL is thoroughly soaked is called hydrostatic pressure’.
2nd LAST paragraph, ‘After compaction, soil is under compression like a spring and CONTINUES to push against the foundation…in practice, sand and gravel densify or compact more readily than silts and clays, creating LESS of this springlike force-- one more good reason to use them for backfilling’

Lateral-horizontal soil pressure. And the BEST drainage to help that is backfilling with most–all gravel.
6th paragraph… one builder here ‘gets’ it’ (and those like Mr Cyr!)

And again, am on board with Mr. Mayo (no he doesn’t need my dumb az to agree, just saying) that, ‘you can’t fix stupid’… the house, a basement, was built where it shouldn’t have been, swampy area etc etc.

Sure, one should have their grade sloped away from the house/basement.
Sure, one should have gutters and long extensions, yep.

But THAT is not why most basement leak/seep and sometimes have some mold or efflorescence on some of the interior basement wall, nope.
And very often, least here is Michigan, all I friggin ever hear from many HI’s (no, not any Nachi members) is sellers/buyers can solve their leaky basement or crawlspaces by raising and sloping the grade etc. This is nonsense!