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House Settling / Basement Cracks (bc) DOWNSPOUT DRAINAGE ??

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  • Jun 12th, 2015 3:09 pm
Deal Addict
Apr 29, 2010
1044 posts

House Settling / Basement Cracks (bc) DOWNSPOUT DRAINAGE ??

Our older 1963 home has an area of 1200 square feet. We're experiencing more significant foundation settling issues and are wondering if it is to do with the newly buried downspout drainage...

Because we were installing a new driveway we decided to have 4 different roof downspouts run below ground toward the backyard. There it drains into a hand-dug pit. The underground dirt pit is about 20 feet from the home with dimensions:4 feet wide and 4 feet deep. There are small pea stone pebbles filling the hole from the bottom to about 1 feet below the grassy surface. I've been told our surrounding soil is mostly clay. The drainage from the downspouts is non-perforated Big-Os which connect with one Tee and one Wye. The distance from the furthest downspout to the pit is maybe 60 feet. The distance from the closest downspout to the pit is about 20 feet. I cant speak to the sloping of 2 of the downspouts below the driveway (the contractors had the job done before i could inspect) but the other 2 slope toward the pit from 1 foot below ground at the house to about 4 feet below ground 20 feet away.

The underground drainage was put in place about 7 months ago. We've been doing other renovations but have noticed a lot more house settling than usual, cracks appearing in fresh drywall, significant upheaval of basement concrete flooring (there was always a crack but the upheaval is far more this year), some moist walls, strange noises at night. We are concerned the downspout drainage could be the source of the significant house settling.

A few questions:
  1. Is my drainage pit suitable for accepting downspout drainage from the roof? I've always wondered about an underground large barrel with popup discharge head to eject water instead of hoping it would leak out into the underground soil.
  2. Is there an efficient inspection tool i can use to trace the Big O for any leakage along its path? Take note 2 of the 4 downspouts (40 feet) are buried below the concrete driveway.
Thanks for any tips to getting to the bottom of this
3 replies
Sr. Member
Jan 11, 2008
646 posts
So all of the roof runoff is going to this 4'x4' pit?

The armchair thinking would also assume you also have normal yard runoff that would also end up in that pit. So I'm not sure sure if that pit can get too much water because it's dealing with both your roof runoff and what is coming from the lawn. Is the area squishy after it rains? Can you disconnect the downspouts for now and let the water flow like they did before?
Deal Fanatic
User avatar
Oct 19, 2008
7303 posts
Stick a garden hose in each of the 4 downspouts, should be able to do that by unscrewing connection near the ground. Run the hose, see if its uniform flow from all 4 downspouts or if one of them backs up.


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