# Footing Drains



## jjtt (Dec 20, 2005)

I built a house last year for a client that was in a wet area. We excavating the site (mostly clay), brought in 40 yds of scalpings, a sand and pea gravel mix, and poured the foundation. Footing drains and down spout drains were installed to code but we are still getting some water in a corner of the crawl space. I installed 4" perf. pipe around the perimeter. Bottom of pipe is level with bottom of footing all around the home. Backfilled w/drain rock and covered with filter fabric and native soil, drains to ditch. H.O. says footing drain should have 1-2% slope and my responsibility for any water in his crawlspace. Water in C.S. is only evident during hard rains and seems to disipate afterwards. Not good enough for H.O. 

Any suggestions or comments?


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## Coastal (Dec 20, 2005)

Its code in my area to put perimeter drains on a slope, and I would hope it is everywhere. You might have to put a sump in and pump it out to the ditch. Whats the slope like to the ditch from the level of the perf pipe?


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## jmic (Dec 10, 2005)

jjtt,
Did you run footing pipes and leader drains into same system or are the leader drains going into their own solid pipe system. What kind of pipe did you use for footing drains and leaders system ( please don't say that black corragated _rap that comes in coils ). If they are seperate systems do they each run to daylight or did you connect them to one runoff? Does any water come out of the runoff during moderate to heavy rains? Maybe you have a crushed outlet pipe impeading the flow out. A little more info. would help. Good - luck,
Joe


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## K2 (Jul 8, 2005)

Where is C.S.?? Colorado Springs?? Yes the drain should have slope. One of the problems I found was that the excavation holes are not perfectly level and if they are pitched 1 in. in the wrong direction that can create a problem. Also if you dug a hole in clay and dumped sand and gravel in, that would be like dumping sand and gravel in the bottom of a swimming pool. No place for the water to go. I would have put a drain at the bottom of the excavation also. If the excavation was reasonably level you could still probably drain it fairly easily. If you had no ground water in the soils report and all you are dealing with is surface water that should be able to be dealt with. I personally would be leaning toward draining the bottom of the excavation. I did that one time and it was not too expensive and it worked. RT

Edited: One more thought. Where the water is collecting in the crawler is probably the lowest point of the drain. If you can daylight from there that would probably solve your problem. <P>

Seems like sand and gravel would be the wrong material to be putting over clay in an excavation. We always used our red roadbase which would shed water.


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## DecksEtc (Oct 27, 2004)

I'm guessing he meant "C.S." to stand for "Crawl Space"???


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## Tom R (Jun 1, 2004)

I thought it was, - - never mind!! :cheesygri


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## K2 (Jul 8, 2005)

Oh yea. Crawlspace.. Forget what i said.


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## Guest (Dec 28, 2005)

*in marin co all our drainage is inspected by a soil eng.*

on site while it's done! slide country! sdr 35 pipe 3/4" crushed gravel,
filter fabric . compaction in 6" lifts. then the surface is swalled to drain
water is drained with a defuser 12" below found on hillslides. tite line for down leaders [NEVER MIX with footer drains] all pipes have surface clean outs. it.s expensive and good.

some times in marin co.when you come home,

your house comes down the hill to greet you tool


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## chrisherk (Dec 11, 2005)

everything ive done to date has had foundation drains, but i bid a job recently and the septic plans says i dont need them. The soil is all sand and the high water table is actually below the footings. I did figure them in my price, just in case, but i dont think i should put them in. any body ever run into this?
chris


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## jmic (Dec 10, 2005)

Chris,
In rear circumstances sometimes in order to keep seperation distances between septic system and footing drains (usually a short section ) an engineer will have you use tight pipe to make the connection to the rest of the footing drain loop. I'de never consider doing a full basement without or even crawlspace area for that matter without foundation coating and drains. Water tables can change over the years for one reason or another. It's just cheap insurance compared to dealing with water problems down the road.
Joe


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## ApgarNJ (Apr 16, 2006)

*holes up or holes down........*

I usually have the mason install my foundation drains using sch35 s&d perferated pipe. The mason just poured the footings for a new addition we are about to start framing and i decided that I am going to do the drain pipe on this job. My excavator was there supplying me with stone to use while installing the pipe and said that the holes should face down,
and I thought they should face up, and that the top of the pipe should be a few inches below the top of the footing, so if any water comes down from above or even from ground water, it will pour into the holes and run out the pipe. he said he's always seen the holes faced down in a few inches of stone, then cover the pipe with clean stone and filter fabric, and back fill. 
what do you guys do, holes up or holes down? just doesn't seem right to me to put the holes down, but he says it will catch the water faster as it comes up from the ground, but I think that it just makes it so the water has no place to run in the pipe. i made sure there was pitch to the drywell we have to put in later on.


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## Tom R (Jun 1, 2004)

Definitely not my expertise, - - but until you get a 'real' answer, - - I do believe 'holes down' is the much preferred method. Once the water comes up and into the pipe it will run just fine as it will seek it's own level. :thumbsup:


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## kid creole (Jul 11, 2006)

what do you guys do, holes up or holes down? just doesn't seem right to me to put the holes down, but he says it will catch the water faster as it comes up from the ground, but I think that it just makes it so the water has no place to run in the pipe. i made sure there was pitch to the drywell we have to put in later on.[/QUOTE]

according to the research i'm doing for my g.c. lic. holes should be up on a slight angle away from house.does'nt make to much sense for the hole to be down as the pipe and gravity won't work together to drain.


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## jmic (Dec 10, 2005)

I'll usually run one set down and the other set of holes towards the footing, right or wrong as long as you use plenty of clean stone and cover good with fabric the water will find it's way into the pipe and on out to where it's piped.:thumbsup:


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## ApgarNJ (Apr 16, 2006)

yeah, i slightly angled the pipe so that the holes were not just dead center on top. figured the water could get in a little easier. i have 3 inches of so under the pipe and the whole bottom around the footing is clean stone. we'll add a little bit more over top of the pipe once the block work is done.
thanks for the info guys.


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## jmic (Dec 10, 2005)

ApgarNJ said:


> yeah, i slightly angled the pipe so that the holes were not just dead center on top. figured the water could get in a little easier. i have 3 inches of so under the pipe and the whole bottom around the footing is clean stone. we'll add a little bit more over top of the pipe once the block work is done.
> thanks for the info guys.


We usually mound 6" - 8" of stone over the pipe.


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## denick (Feb 13, 2006)

This is the correct way to construct a footing drain. With the holes in the pipe on the bottom. The dark outline is fabric on bottom, outside and top. The stone goes up and over the footing at least 2". The pipe is set level with 2" of stone below it.

Set this way the water in the drain starts to run through the pipe when there is 2" of water in the stone which should be 12" below the floor height if a 4" floor is poured on top of the footing height.

If you turn the pipe with the holes up the water has to build up to 5" of water in the drain before it starts to enter the pipe. If you raise the pipe so that it is near the top of the footing there can be 9" to 10" of water in the drain and be at the bottom of the floor height before it enters the pipe.

In any drain built with stone and pipe the water only enters the pipe when there is an overwhelming amount of water moving through the ground.

Water coming down from above will always find its way to the bottom of the drain through the stone before it enters the pipe.

I can't seem to get the picture into a format I can upload as a picture.


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## tgeb (Feb 9, 2006)

I agree with Nick 100%! Holes at the bottom. :stuart: 

Here we use the flexible corrugated pipe with perforations around the entire pipe. Only around the foundation and bedded in stone, never for the outfall or daylights, PVC for that.


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## jmic (Dec 10, 2005)

tgeb said:


> Here we use the flexible corrugated pipe with perforations around the entire pipe.


:thumbdown :thumbdown :thumbdown Can't say that I have much faith in that choice of pipe.


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## ApgarNJ (Apr 16, 2006)

I don't use that black corrugated stuff either, it's all junk. my excavator has to replace that stuff all the time on various jobs that he gets calls for, not really for footings but for other drains. 
well. i guess next time i'll put the holes down. the water will run in the pipe and out the end, so it'll be fine.
the whole job is on a hill too, so drainage is really good anyways.


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## tgeb (Feb 9, 2006)

jmic said:


> :thumbdown :thumbdown :thumbdown Can't say that I have much faith in that choice of pipe.


I agree Joe, but when that is what is specified, that is what we have to use. :sad: 

We have to install what they ask for, especially when the alternative is a little more expensive. 

We get good service from that type pipe when it is installed correctly, (bedded in plenty of stone, and covered well with filter cloth).


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## jmic (Dec 10, 2005)

I hear you Tom. I never had any luck what so ever using that stuff with our soil conditions around here, gave up on it 20 yrs ago.:laughing:


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## denick (Feb 13, 2006)

If we could get a few more people to reply about this topic it seems that we could come up with a concensus and this might be a topic we could publish as an information article where ever Nathan puts them.

There are a few details that could be added to cover most all situations contractors might find.

????


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## jmic (Dec 10, 2005)

Nick,
In order to be effective it's imperative that you use perforated pipe.:w00t:


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## denick (Feb 13, 2006)

Joe,

I thought you might get your crayons out and draw us a detailed construction drawing.

I do think we should get as many people as we can from as many different parts of the country to contribute on this and come up with an article.


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## jmic (Dec 10, 2005)

Nick,
Have you been using pvc glue today again?:laughing:


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## MC Excavating (Jan 26, 2006)

I put holes down on drain pipe.

Think about it. Does water bounce around through the gravel or drip down directly into the hole in the top of the pipe? 

Water seeks its own level. It will always be level. So when water drips down through the gravel it will fill up the trench with a level layer of water.

I think we can all agree that less water resting in the trench next to the foundation is better. Less is better.

Well if you have the hole facing up, there will be about 3.5 inches of water sitting in the trench before it can reach the holes at the top to drain out.

If you put the holes at the bottom, there will be about a half an inch of water before it can get to the holes and drain out. Less water sitting around is better.

Now keep in mind that footing drains are not perfect and wont / cant get all the water out. But its better than nothing.

Now some might be thinking, "well why use 4" pipe then?" Its not that the water needs to sit exactly in the cradle of the bottom of the pipe to drain because the way each row of holes is spaced, its not that much surface area. If you get alot of water in your trench from a realy heavy rain it alows a greater amount of water to exit more freely to prevent to much water pressure from building up.

Remember water will always follow the path of least resistance. Water can create high amounts of hydraulic pressure. We all now how strong hydraulics are! Dont let the path of least resistance be your foundation.


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## denick (Feb 13, 2006)

MC,

Glad to have your input and with you on the other side of the country we will need your input on the article we are going to write about this topic.


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## tgeb (Feb 9, 2006)

Who is the direct? 

Sent from my SM-G970U using Tapatalk


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