# Frost wall drainage question



## Willie 2 (Feb 4, 2010)

I am trying to understand the need for a weeping tile system at the footing of a 4 foot deep frost wall where the interior and exterior of the wall is at grade level, as in no basement. The local planner wants the Big O pipe gravity fed into a sump pump ( gonna have to be 5 feet in the ground ) and then discharged on to the lawn. I am no foundation expert but would like to understand the theory. Helpful answers would be appreciated.


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## ch0mpie (Nov 30, 2005)

Is 4ft the frost depth in your area? How deep is the groundwater at your site? Hes either worried about frost heave or water pressure lifting the footings, or he put the wrong detail on the drawings.


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## Rory Read (Feb 5, 2010)

*ask politely...*

Our code does not call for foundation drains unless the wall encloses usable or habitable space.

You might very gently, very deferentially, ask if the planner is overlooking the fact that this is a crawl space.


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## Willie 2 (Feb 4, 2010)

It me that is the issue, the frost wall is put in the ground and the grade level is the same inside and outside the concrete wall and the footing. On top of the concrete we are doing a 4 foot pony wall ( wood ) to make up the crawl space which is basically above grade. What confuses me is they are calling for a 3 " concrete floor at grade level inside the crawlspace ( understandable ) but the drainage pipe is 4 feet deeper in the ground. Frost penetration is 4 feet so what is the need to have a drain tile 4 feet below the " floor " on the crawlspace.


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## Morning Wood (Jan 12, 2008)

Having the slab would be nice, but doesn't seem necessary. If they are worried about moisture maybe you could just do rigid foam, poly and crushed stone on the crawlspace. as for the foundation drain, I think having one is a great idea, but can it be run out to daylight somewhere on the property? Feeding it to a pump and then pumping it up to the lawn seems weird. How about feeding it into a large dry well and then using the water in the dry well for lawn and stuff.


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## Willie 2 (Feb 4, 2010)

Morning Wood said:


> Having the slab would be nice, but doesn't seem necessary. If they are worried about moisture maybe you could just do rigid foam, poly and crushed stone on the crawlspace. as for the foundation drain, I think having one is a great idea, but can it be run out to daylight somewhere on the property? Feeding it to a pump and then pumping it up to the lawn seems weird. How about feeding it into a large dry well and then using the water in the dry well for lawn and stuff.


Morning Wood : Running it out to daylight won't work, it would be uphill 4 feet to grade level. That's kinda my point it seems pointless to pull moisture out of the ground and redeposit it onto the grass ?? The % of moisture would be the same on both sides of the frost wall without a drain would it not ?? and it's four feet below the crawlspace floor so is there any real concern here ??? Again, I am no foundation expert so I am just looking for opinions. I do install many items such as flag poles, commercial signs and we do a below frost level base but never provide any drainage.


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## northwood_677 (10 h ago)

We're having a similar issue today with a building inspector who insists that drains are necessary. However, my 40 yrs of experience as a builder, an engineer, an excavation contractor with 50 yrs experience, and the concrete contractor...oh yeah, and common sense...all say it's unnecessary and a waste of time and money.


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