Waterproofing An Existing Slab On Grade

[GlobeTrekker]

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I have an existing below grade, slab-on-grade foundation that
is having water issues. Water is entering the basement areas.

IMO, I believe that the exterior walls need to be evaluated
for water intrusion and points of entry for the water /
moisture coming in to the basement.

QUESTION # 1: What is the(best)method to recommend
to a homeowner with this problem?

QUESTION # 2: Who typically performs these types of
analysis, ..Structural Engs., ..Civil Engs., ..Forensic
Concrete Engs. or other?

Thanks!


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[bridgebuster]

"I believe that the exterior walls need to be evaluated for water intrusion and points of entry for the water /
moisture coming in to the basement" - Good idea. We need more info.

What is the wall constructed from? Where I grew up in NY, many houses were constructed in the early 20th C using cinder block, which was prone to leakage over time.How is the terrain graded? Is there a high water table normally?

Q. What is the(best)method to recommend to a homeowner with this problem? A. Let's figure out where the water's coming from.

Q. Who typically performs these types of analysis, ..Structural Engs., ..Civil Engs., ..Forensic Concrete Engs. or other?
A. Someone who knows what they're doing.

 

[GlobeTrekker]

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Thanks bridgebuster for the reply! I do not have any more info
to provide! I am getting this info second hand!

Apparently, there is water coming up through the existing concrete
floor, and I was asked how to evaluate the actual construction of
the "slab on grade" foundation to ensure that some type of approved
barrier or coating was installed prior to the pour.

Regarding the "someone who knows what they are doing", ..therein
lies a dilemna all on its own. Let's assume its one of your
closest friends house, and they don't have a clue as to which
direction to go. What would you recommend, ...searching the internet
for Home Inspection companies who market & tout their services,
...ask your engineering colleagues for competent companies who
would actually evaluate the structure "accurately", other?

Essentially, how would the average, unknowledgable homeowner find
a company that won't sell them some form of "snake oil" inspection
service that won't accurately diagnose the conditions and solutions,
without getting taken to the cleaners, ..all the while raping &
pillaging them?

Yes, yes I know the old statement of Caveat emptor applies to
most of life, but in the vein of trying to help someone find a
competent company, what would you (and others) do?

Thanks!

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[IRstuff]

Most large real estate companies know a cadre of contractors for their stuff, such as rehabs, small demo's, etc. They may also know reputable engineers as well.

They tend to be more expensive than run of the mill guys, but presumably, that's balanced by some level of trustworthiness and reliability. My agent had a guy who was only slightly above average cost, but we decided to go a lower bid. Not quite as pretty and customized, but it was half the cost.


TTFN
faq731-376

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[msquared48]

How old is the home?

It sounds to me like the foundation drains at the exterior walls could be plugged, allowing the water table to increase, but the presence of an artesian spring, or clay lens with a perched water table could present a similar situation.

Lots of possibilities here...

Mike McCann
MMC Engineering

 

[Ron]

Home inspectors are a poor source for something that requires engineering evaluation. It could be groundwater, it could be failing waterproofing, it could be a variety of things....as BB noted, it requires evaluation by someone who knows what they are doing, i.e., someone who has experience with this type of water intrusion.

You start with the manifestation of water intrusion. Is it through the floor slab, the walls, at the intersection of the two or all of the above?

Where is the groundwater? Is the condition transient? Is there a subsurface drainage system in place? Does the condition occur only after a rain or is it relatively constant? What is the construction? Do you have plans? Is there evidence of an exterior waterproofing system?

Lots of questions...few answers. Don't try to treat symptoms...find the source.

 

[GlobeTrekker]

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Thanks to all for the input! Lots of good info!

Ron,

IMO, one of the most important issues in this application,
is how to find that competent company that will accurately
diagnose the problem, or problems, ..recommend a solution
and all at a fair price.

The unknowledgable homeowner has got quite a daunting
task ahead of them!
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[Ron]

Assuming you are in the US, if you can give your location, I might be able to recommend someone in your area.

 

[GlobeTrekker]

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Ron,

Thank you for your kind offer! Presumably, the subject property
is located somewhere in / around Washington, D.C.

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