Foundation Drainage

[zeramant86]

So I just recently purchase a house about a year ago, and I'm noticing one corner of my basement seems to be getting some moisture issues. My basement is unfinished, the slab is not sealed, but the walls are painted with regular latex paint. What I'm seeing is that my block on one corner of the house is bubbling, I'm assuming due to moisture coming through the block. I'm not certain that the outside of the block is sealed with tar or similar, I haven't dug down yet.

I guess my question is this, what is the best option to prevent this?

1) Use a vapor sealer to seal the block on the inside, after removing the paint, then repaint over it afterwards
1A) Would sealing the inside of the block only allow water to penetrate the block and weaken it over time?
2) Modify the back fill and draining to move water away from the house
3) Dig out the foundation, and seal the outside of the block

 

[nealtw]

Welcome to the site. Sealing the inside will only allow the block to fill with water until it finds a new way in. The best if you can is to dig down the outside, makesure the perimter drain is working right and waterproof the wall. Sloping the soil away from the house is a must and if down spouts are running into the weeping tile around your house you may want to devert them away. If deverting the downspouts work you could run a second solid pipe just for them, dosn't have to be as deep as the weeping tile.

 

[Wuzzat?]

Water seeks its own level and your basement floor is level so I'm wondering if your water meter registers usage even when there is none because of a leaking buried pipe in that corner.

 

[zeramant86]

My water supply line is on the other side of the house, so there isn't a buried water line there. That one at least I'm sure of.

So I have a possibly dumb question. I know having water sitting within the block isn't going to be good which would be the result be sealing the inside only, but would it weaken the block structurally over time? I'm just wondering how much harm there truly would be in that.

I do have a certain amount of backfill, not as much as I'd like, but it should be sufficient to drain water away from the house, the low point is about 10'-12' away from the house.

I wondered if the drain tile for that side of the house might have gotten damaged when the replace the corrugated piping coming from the guttering, or the corrugated itself not carrying water away from the house.

Also, my house cuts into the hill, and the issue is on the side towards the hill. Would it be worth putting a french drain in in the low point 10'-12' from the house to try and divert water around the house?

I think this is my tentative plan of action.
1) Dig out at least that part of my foundation
2) Verify drain tile isn't damaged in that area
3) Seal the outside of the foundation in that area
4) Backfill, and redo the corrugated for guttering to go further from the house using non-perforated material.
5) Soda blast the inside of the basement wall in that area so that any future moisture can be seen
6) Once lack of moisture is verified, seal the inside of the basement wall

I'll try to get a couple of pictures to illustrate what I'm trying poorly to explain, do you have a particular image host that you use for this site?

 

[nealtw]

To post a photo from your computer.
While you are at quick reply hit the button below (manage attachements}
a box will come up (choose file)
find your photo and hit (open)
then hit the button (upload)

Block will fill with water and water will travel sideways until it finds a way out. Or it fills up to a level above the frost line.
If you are backed into a hill repairing the weeping drain would be more than a chore.
Getting rid of surface water and down spout water would be the first step. Like you said solid pipe for the down spouts and maybe weeping just below surface to take away water coming down the hill.
That would be where I would start
If that dosn't do the job you will be into something like this.

 

[zeramant86]

Ok, that makes sense. So I take it that you all host your own photos then, you don't use a 3rd party server?

So I'm guessing that is a water resistant membrane that is put around the perimeter of the block, on the inside?

I'm assuming the other is a semi-buried sump pump?
Where does the pipe go to through the wall there?

 

[Wuzzat?]

Getting rid of surface water and down spout water would be the first step.

Yes. I've heard a minimum of 6' from the house.
It's a good idea in any case and will give more info about the root cause or it may just fix the problem (which gives a lot of info about the root cause ).

The suggested order of the steps after that are:
least costly and most likely to work
down to
most costly and least likely to work.

To see the effects of a heavy rainfall you may need to wait 24 hours.

My sump outlet pipe is also pitched slightly upward to throw the water onto the ground far from the house. IIRC, physics says to pitch it upward 45 degrees for max horiz. throw (for a projectile) but there may be practical considerations for using less pitch and the pump curve is one that comes to mind.

 

[nealtw]

That membrane is designed for the outside of the foundation wall. Usually used when the soil is like clay and not likely to transport water down to the weeping tile.
When used on the inside with block walls, they remove 1 foot of concrete floor around the perimeter install weeping tile and sump. Witha wet block wall they drill hole in the bottom blocks to let the water runn out and then put this membrane up to it takes any water from the wall down past the floor into the tile.. I you are working on the back side where the ground level is high you will want to run a pipe out toward the front of the property away from the house.

 

[zeramant86]

Figured I'd upload some pictures here. This is what I'm looking at. You can't see it extremely well, but the rightside if the uphill side of the house. It slopes towards the house, and the backfill begins a few feet out from the deck. Also, the guttering for the back side you can see goes downhill along the side of the house, no further than about 3 ft from the house.

 

[nealtw]

As the water is flowing down the hill and building up against the house, pumping into the back yard is like wiping your rear with a wheel, it will just keep coming back
You need to find out where the water is going from the down spouts and is it attached to the weeping system at or below floor level.
If it is seperate from weeping it will tie into it somewhere out front, you could tie into that.
If it is the same system you would be wise to run a new pipe for the downspouts to the front and then tie it in.
I suspect you are hooked up to the city storm sewer system, it's hard to imagine a subdivision on a hill with out it.
Digging up the back outside and waterproofing properly is always the best choice but in this case, pretty tuff to do.
First is make sure the downspout are not dumping water to the weeping tile, if they are run new pipe.
Maybe re-shape the back yard so there is a little valley between the hill and the house that slopes away and around the house.
If all that fails the interior drain system is what would need to be done. Givin the slope of the propety with a little digging it might be able to be run to the front with out a pump.
At this site note the floor is cut away about 18" from the wall, the perferated pipe runs along side the footing, holes are drilled in every block to let the water come in.
The curtain of plastic runs all the way down to over the pipe and then the floor is repaired.
http://www.aquaguardinjection.com/r...n-waterproofing/interior-weeping-tile-system/

 

[zeramant86]

As the water is flowing down the hill and building up against the house, pumping into the back yard is like wiping your rear with a wheel, it will just keep coming back
You need to find out where the water is going from the down spouts and is it attached to the weeping system at or below floor level.

The downspouts for the guttering go towards the front of the house near where the electrical drop/meter is on the left there. They are on a downgrade, but I don't think they travel far enough from the house.

If it is seperate from weeping it will tie into it somewhere out front, you could tie into that.
If it is the same system you would be wise to run a new pipe for the downspouts to the front and then tie it in.

The downspouts are not tied into the drain tile around the foundation, that I know for certain. My concern is that the drain tile may be crushed or damaged til it is obstructing or restricting flow.

I suspect you are hooked up to the city storm sewer system, it's hard to imagine a subdivision on a hill with out it.

Too my knowledge, nothing on my house is hooked into it, I'll take a few more pictures to illustrate.

Digging up the back outside and waterproofing properly is always the best choice but in this case, pretty tuff to do.

Yeah, I'm half tempted to dig the entire back side and seal it, and half the sides to the downgrade.

First is make sure the downspout are not dumping water to the weeping tile, if they are run new pipe.

This will only be true if the corrugated down spout is either perforated, or got crushed during the backfill process.

 

[nealtw]

On a really dry day, run a hose down the down spout drain and then go listen for water running and manhole, street drains or access points, turn off the water and check to see if noise stops.
Digging the back out would be best but I was looking at deck removal, re and re the AC unit and working in a trench that will be at least 9ft deep plus all the loose dirt piled on top of it when we know the ground is transporting water. The origanal hole dug for the house extended out five ft so it can not be trusted as stable fill Best left to the pros.

 

[zeramant86]

I'll take a few more pictures this evening, it should help illustrate the issue better. My downspouts empty into the driveway. There's some waterflow, but I'm not sure how much there should truly be.

Digging out to seal the outside foundation would require a pit wall, right? I'm not sure if that's the name, but a wall they use to keep dirt from collapsing in on you, while you're in the pit.

Yeah, the deck and AC would be a pain to do, but if it's the right thing to do, then that's what I'll do. My stepdad does earthwork, so hopefully I can get the family discount. I know how to do the deck and AC, but I don't have the tools to discharge the AC unit, and store it.

I'm looking at staying in this house for several years, so I want to make repairs the right way rather than try to bandaid them, ya know.

 

[nealtw]

I have seen where some soffet was removed and an AC unit was lifted off the ground with a cable come-a-long hooked to the rafters above to save the money of re-re.
Shoring for the trench can be as simple as sheets of one inch plywood standing against the bank and wedged to the house with timbers. Keep rain out of the dirt pile is a must, cover all loose dirt with sheet plastic.

 

[Wuzzat?]

IIRC correctly you can map out basement wall moisture problems by taping a plastic sheet to the wall for 24 hours. You might find areas that are different from the rest, better or worse.

The more clues you have the less wasted labor & $.

A topographic map of your entire property would probably help for checking for correct slopes but you'd need one of these spinning laser levels or a long level. This map will show where soil needs to be transferred, from one place to another.
Ideally you'll have no excess soil to dispose of, and no shortage.

 

[zeramant86]

Figured I'd post an update. with a few more pics. We had a good rain the other day, so I was able to get some pictures.


This one is of the area directly behind the porch. My plan is to run the french drain directly through the center of this.


This is behind the AC unit, directly over from the previous photo. French drain will run through this too.


Both the front and back guttering come out, and empty into the driveway, which is sloped away from the house.


The storm drain can be seen next to the telephone pole. My corrugated doesn't run into this, it basically just siphons off surface water from the looks of it. I'm planning on running my corrugated, and my french drain over to the storm drain.


This is more just to show how close the corrugated stays to the house.

 

[nealtw]

That sounds like it will get rid of alot of surface water and may be all you need to do.

 

[zeramant86]

Fingers crossed. I wonder if part of my issue is the loosened soil where they dug up part of the gas line last year. It comes in right beside the AC unit, and you can see where they dug by the sunken area. Path of least resistance and such. That also would be near the same wall where my moisture is entering the basement.


Blue hatch is roughly where my low areas seem to be
Green is where I'm seeing moisture issues
Red is corrugated and drain lines


Purple is roughly the proposed french drain location, with one surface spout possibly near the curb.
Red is the modified corrugated


On a completely unrelated note, how far should I stay away from the corrugated lines and french drain when planting trees? I'm sure it varies by type, but is there a general rule of thumb?

 

[nealtw]

Your new trench wants to be as deep as they dug for the gas line, I would use perferated hard pipe and as you will want to cover this with gravel fabric and topsoil I would install yard drains and shape the yard to run surface water to them, They will also give you a point of clean out. Not sure about trees but some are worse than others. You should be able to reseach that or ask questions in landscaping.

 

[zeramant86]

We have a hardware store that is geared towards contractors, they actually sell a corrugated line that is pre-wrapped that you can purchase in a roll. You just have to cover it with gravel.

What do you mean be a yard drain? I'm not sure if this is what you mean, but do you mean where they dig a larger hole straight down and fill it with progressive sizes of gravel to increase drainage?