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Advice on Retrofit Water Drainage For Foundation 4 FT Under

7K views 13 replies 7 participants last post by  cloves 
#1 ·
Hi everyone, I was hoping to get some advice on my water problem. I have a house that is a split level.

I recently dug up part of the wall to explore the system. The wall was parged and then tar was painted on and a thin plastic was placed over that. The basement is exactly 4ft underground. The previous owner of the house has an interior drainage system installed on one of the walls. Contractor dug up the concrete used a dimpled membrane (miradrain?) and redirected the water to a sump pump. Then they punched weep holes into the block so when it rains and water gets into the block, the water flows under the membrane and towards the sump pump.

The system on that side of the wall works perfectly. Unfortunately, one of the other walls seeps some water when we get heavy rains. I want to completely stop the water from getting into the house.

I have read of a few methods and was hoping someone could recommend what the best option was.

Plan of Attack:
I was going to dig up the foundation 1 wall at a time. Method 1 is less digging since I don't have to go all the way down to the footing.

Method 1:
- Add Miradrain membrane to all the walls. This membrane will essentially keep water from entering the walls of the foundation and most likely push water down toward the footings.
- Add a curtain drain 4ft to 6ft from the foundation wall. (I have read a few times now that anything close then 4ft will actually suck water into the wall)

Method 2: (This is a huge amount of work)
- Add Miradrain membrane to all the walls.
- Add a a footing drain (This will require a lot more digging)
- Routing the footing drain away from the house will also require a lot more digging.

My concerns with method 1 is that if I have no footing drain and some of the water makes it past the curtain drain then I am essentially pushing water into the footings side. I guess the big question is will the curtain drain 4ft to 6ft from the foundation effectively capture all water coming at it.
 
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#2 ·
1st, thankfully 4' isn't much so you won't have to shore up anything,,, 2nd, interior systems do nothing to prevent water from entering,,, 3rd, its better to prevent interior wtr than manage it,,, & 4th, always seems to come down to $$$ :huh: when the final decision's made.

parging AND tarring's a bit unusual but its done,,, we use foundation mastic then delta drain ( or equal ) system leading to the toe drain which's properly installed in a filter lined trench,,, the 4" pipe leads to daylight or, in some cases, an exterior sump ( collection point ) & mechanical discharge of collected wtr ( zoeller pump )


we ' dig ' these systems every day,,, you'd be surprised at what a good crew can do if properly incentivised :thumbsup:

have done only 1 wall, $$$ MAY have been influenced p/o's decision,,, i'd bet against a curtain drain in this instance.
 
#8 ·
Hi everyone, I guess I should clarify. :yes:

The basement is 7' feet in height. 4' (actually 3'6" is below grade). The trench I dug so far is about 8' long and the width is about 2'. I piled the dirt right next to the hole. I didn't think there was a chance of the trench collapsing should I be concerned? I am going to take some pictures today to share. The other side of house has the same foundation wall but is a slab on grade.

Money is tight and I am basically the one doing the digging (no crew lol). I want to do it correctly. If I decide to go with method 2 and adding the drain tile at the footing, there a lot of extra digging because I eventually have to run the termination points away from the house. I am actually still trying to figure out where you are suppose to run the pipes to. Someone mentioned to daylight which I don't know if it makes much sense in my case considering my lot is flat and bringing the pipe to daylight would mean pitching the pipe up. Still a bit confused by that as I have read it elsewhere.

Reason method 1 would also be easier is the fact that a 2 foot trench 6' feet away from the house would be a lot easier once I start doing to whole house.
 
#9 ·
I am actually still trying to figure out where you are suppose to run the pipes to. Someone mentioned to daylight which I don't know if it makes much sense in my case considering my lot is flat and bringing the pipe to daylight would mean pitching the pipe up. Still a bit confused by that as I have read it elsewhere.

If there is no way to pitch the pipe to daylight with some pitch away from the house, you will need to add a sump crock (pit) and pump. I've never seen one installed outside, maybe IRC can add to that. Here, they are only installed inside the basement, which is good IMO, as it's easier to monitor.

Reason method 1 would also be easier is the fact that a 2 foot trench 6' feet away from the house would be a lot easier once I start doing to whole house.
I don't see this as an effective route to waterproofing the basement. I would only recommend Method #2.

BTW, where does the existing interior draintiling (the one retro-fit wall you mentioned) currently drain into?
 
#10 · (Edited)
Go with the footing drain.

It's your choice whether to put that just inside (digging up the basement floor) or just outside (digging around the outside).

The outside version works a little better but you would need a 4 inch pipe through the foundation to get to an inside sump pump pit. Outside sump pump pits can work but need special treatment in cold climates to keep from freezing.

If you dig around the outside, while you are at it, paint waterproofing compound on the foundation wall.

Note that draining to daylight works only when there is a significant visible slope down from the foundation since the drain pipe must slope down and also "catch up" with the surface sloping down.

Curtain drains buried at less than foundation footing depth can reduce surface water coming at your house, say from an uphill neighbor, but don't help remove water that already soaked below that level.
 
#11 ·
question

I have no more info to add on the "fix", but I'm curious about why you have water around the house to start with. Is this ground water, or from above (rain, run-off, etc)? If it is ground water, then big ouch. If it is from above and can be prevented (gutters, over-hangs, dirt really sloped away from the house, etc), by all means to that after you do whatever w/ the drain tile, etc.
 
#12 ·
Thanks for all the feedback everyone.

To follow up:
The existing interior drains into a sump pump. We haven't a problem with that wall its another wall that doesn't have that drain installed that has been seeping.

The water that is entering the basement is occurring when we get heavy heavy rains. We have gutters on the house. I still need to better grade the house around the house. Previous owner of the house has some landscaping down and they put mulch that is creating small pockets of water etc. But I still think the safest bet is to attack the foundation.

Also I was thinking of using some thoroseal on the outside but I may just use a product by karnak that is made of asphalt since the I don't see an easy way to remove the coat that's outside already.

Quick question technically isn't it possible to connect the drain tile to the city sewer pipe? (the one where the toilets flush into)
 
#13 · (Edited)
In practically all cities it is not permissible to drain rainwater into the sewer system.

The sewage treatment plant is able to process only X gallons of water per hour, More than that and sewage that hasnt dwelled in the treatment plant tanks long enough to digest the material has to be released to the river or ocean. Like having to release criminals from jail before their sentences are up because too many new prisoners are coming in and the place is getting overcrowded.

A septic tank system will also overload if rain water is poured in. The leach field might not be able to absorb that much and then the house plumbing backs up.
 
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