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Interior weeping tile double duty as earth tubes

billstyles | Posted in General Questions on

Hello all, 

I have a crazy idea I just wanted some thoughts on, if you don’t mind. 

My 1960’s home here in southern Ontario has a concrete basement floor sloped toward a central drain, which I presume goes out to the city’s sewer. I am unsure if I have exterior weeping tiles that would be connected to this drain. I’ve only had small leaks a few times just in the corners where my house is attached to the neighbour (semi detached) and that was during particularly heavy rains when the ground is still partially frozen and before I fixed the grading around the house. I had the drain lines scoped with a camera and the guy couldn’t really tell if any weeping tiles connect. If they exist, they are likely clay and probably aren’t in the best of shape. I’ve settled on interior weeping tiles and sump since I’d like to finish the basement and I don’t want to run the risk of the leaks getting worse and ruining any work I do, and I also don’t want to dig up the exterior due to the nice landscaping. Did a radon test and it is not of concern. 

Anyway, while I’ve been thinking about interior weeping tiles, I’ve also been reading about earth tubes mostly just for fun. It seems to me there could be a way to integrate a cooling system with this system since the basement is usually a fair bit cooler in the summer.

Hear me out.

I’d be using 4″ perforated pvc pipe for the weeping tiles. Why not have a vertical solid 4″ pvc pipe connected to these going up the basement wall to outside as an air intake. On the other end of the basement, have another vertical pipe somehow connect to a fan on the main floor. The fan draws air through the intake, which is cooled as it runs around the perimeter of the basement, and exhausts it into the main for for a bit of cooling. It may help keep a constant temperature as well for the upstairs in winter. Heck, you could somehow hook it up to the air intake of a furnace as a way to pre-condition the air so it works less hard.

As far as moisture is concerned, the weeping tile is sloped so I wouldn’t expect any mould growth. It may draw excess moisture from the sump pit, in which case, perhaps just having a dehumidifier would help. Anyway, just an idea that can probably easily be picked apart. Have at it!

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  1. Expert Member


    Efficiency aside, I would be uncomfortable having the fresh air for my house supplied though a perforated pipe that ran though damp, possibly radon-rich, sub-slab fill.

    1. billstyles | | #2

      Thanks for your response, Malcolm! Edit: did a radon test last year, and it is fine.

  2. Expert Member
    DCcontrarian | | #3

    A four inch round duct is rated for 20 CFM. Let's say you get a 20F temperature change on the air, that's 583 BTU/hr. Or about 170 Watts. That's a really small amount of cooling. Depending on the length of the pipe it might not even cover the electricity needed to run the fan.

    There's a reason earth tubes never caught on, air is not a great medium for heat transfer.

  3. Tim_O | | #4

    If you really want some passive cooling from the ground, you would be better off dropping a water line in the ground while you've got it dug up. Run it through a little radiator inline with another duct.

    1. Expert Member
      DCcontrarian | | #5

      And if you're going to that trouble you may as well install a heat pump on the line. And if you're going to that trouble you may as well install a full geothermal system. And the jury is very much out on whether geothermal systems make any economic sense.

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