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Community and Q&A

Passive emergency encapsulated crawl space drain

ylekyote | Posted in Mechanicals on

Hi. I’m finishing the design of my encapsulated crawl space project for this summer. The soil gets visibly damp at times due to a natural spring that moistens my whole hillside once a year but no standing water or droplets ever form. And the soil is sandy and high clay I think.

I don’t think I need a sump pump pit installed and neither does a couple of contractors I asked.

But if a pipe ever leaked (either the supply from the well, or after my cistern/boost pump piping) I’d want a relief so my CS doesn’t become a mountain pool.

My ideas is to install a short 2″ diameter pvc drainage pipe with one-way gravity drain from lowest corner wall of CS to punch thru CMU wall to daylight, above grade. The pipe can be level and work perfectly for that flood drainage, because of the water pressure. I’ll just have it dump into my yard where I can see it. Do you see any problem with that? Flapper valve I guess. With good screens both ends. Maybe double screens, lol. I’d also install a couple of water alarms, but if I’m not home those don’t do much.

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  1. ylekyote | | #1

    I think the negative pressure in the finished crawl space should cooperate with the flapper valve too.

  2. charlie_sullivan | | #2

    There are commercial products that are floor drain seals that open with a little water pressure. I don't remember the name of the company.

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