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Interior foundation drains

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D a v e W

Silver Member
Joined
Oct 23, 2009
Messages
176
Location
Lake Stevens, WA
Ok no laughing, has anyone ever seen the following application.

New interior area drains (4" perf) behind a new interior basement wall separating a existing crawl space. Above the perf pipe will be backfilled with pea gravel over it, perf drain is then connected through the spread footer by a series of (4) 2" solid piping 4' OC :?: These 2" pipes will then drain water into pea gravel underneath the new 3 1/2" basement floor which will be pour on 8" of pea gravel, which will be on commpacted soil. I guess the compacted soil is suppose to make the water flow to the next collector. Once the collected water travels through this gravel another collector system against the exterior wall will then discharge to the exterior perimeter drain system.

Lets just say what above makes sense :roll: There still is no thought as to if the system backs up to prevent water from entering under the slab.

I have never ever seen anything like this, input is needed or am I just crazy. :eek:
 
Re: Interior foundation drains

Do you mean something like this?

IntFtgDrain.jpg


See it often in high water table areas. It is also a repair technique used by BasementSystems and other basement waterproofing companies.

I have something similar to this in my basement, but, without the sump. 60' around the house flat as a table then 6'-10' drop off both interior and exterior drain by gravity. 150 year old house, basement was originally a root cellar.
 
Re: Interior foundation drains

I wish I could so lucky. :lol:

Where the pipe pentrates the spread footing (good so far), remove the pump system, fill in gravel pit with soil, place 8" fill (pea gravel) under the slab. Water to flow flow gravel to the other side of the room (not in a pipe). Set a perf pipe there to collect water that moves horizontally under the slab to the exterior wall. Then reverse the collection process to exit exterior foundation wall the same way as collected. How am I doing :?:

Maybe I can draw this monster if I can figure out how to post it. :?: As the says a picture is worth a thousand words, except there is no picture. I am not allowing anyone to move forward until this is cleared up as to what exactly we are trying to do.
 
Re: Interior foundation drains

I think credit has to be granted for someone having given much thought, tho the sump pump factor appears to be a better approach.
 
Re: Interior foundation drains

Oh I agree, however I do not design this stuff. Actually I don't believe they have a inside water issue. Based on site visit. Did not get any geo reports for this stuff either. I think its more of a homeowners plan for something that doesn't exist as an issue. If we allow this there will be a issue later. :roll:
 
Re: Interior foundation drains

Are you working from plans or has the system been installed?

It sounds like they are trying to collect and manage the potential water intrusion, and although gravity drains are preferred, the sump & pump could be more effective, and is most often used in this area of tight clay and not-very-good drainage. I also see all 4" pipe used - I am not sure there are fittings available for the 2" to 4" connection.

Ensure that it meets the code minimums, so if the system backs up, plugs up, or otherwise fails, it won't be because you didn't do your job.
 
Re: Interior foundation drains

No plan examiner missed it. First site visit yesterday, of course there are no stupid questions, right. So a s I began asking (no plan) about what I was seeing. The full verble plan was revealed as I have tried to state. How do upload a picture/drawing that I have or could sketch :?: Never ever seen anyone try to sheet flow water under a slab from one pipe 18' to another, then exit the building. Just asking if anyone has this method, after working for AHJ in CA, CO & WA I just have never seen this method before yesterday. :roll: Lots of problem with this method :!:
 
Re: Interior foundation drains

since WHEN does the building official design a correction?

Should be never..

site conditions are what they are..

Hello?
 
Re: Interior foundation drains

Dave - Sounds unusual, but plausable. When in doubt get a DP involved. If you cannot find a code path to follow that proves compliance, ask for an Engineers' plan.
 
Re: Interior foundation drains

The DP is changing this thought. The system is now being tight lined outside, have shown us where it will go from there yet. Critical area slope (40%) involved. Waiting to see....
 
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