Need some help with drainage issue, french drain stop working in matter of months

[andyl9063]

We brought a house and noticed water going into garage. It was at the top of the brick wall so that's been addressed. Our house is in Georgia so you have red clay.
The brick wall on the inside is our garage. Water is going into the ground where the red lines are at and draining into garage on the opposite side at the bottom.
1. We did install new gutters
2. Grading is sloped away from the house
3. The red lines represent a new french drain I put in 6 months ago that was working and doesn't work anymore. It was constructed with solid pvc with holes at the bottom. Cover with wrap and back filled with 57 gravel. Then dirt back-fill over top and graded away from house.
4. That wall is made up of cmu and its from 1980 so i'm sure it absorbs water.
5. When it rains heavy, it leaks water into garage and there's red dirt with the water so I assume the clay has already clogged the drain.
6. If I open the cleanout, I'm able to see daylight at the other end of the whole 30 feet pipe so I assume clay has cover all the holes and preventing water from coming in to drain properly.

After researching, I'm debating a few options and would like some professional opinion.

1. Least favorite and costly option: dig everything back up and toss the gravel. Waterproof concrete block wall, dimple board, drain pvc pipe, backfill with concrete sand based on my research on here.

2. Dig and create a swale slopping to the left and drain to backyard driveway. So this means a small mound trench, cover with sand and possibly stones for decorations. Plant and landscape on both sides.
The issue is I'm not sure how wide to go and how it would affect curb appeal.

3. Last option is to dig maybe 12 in trench, lay pvc pipe with holes on bottom, backfill with sand. Cover with some dirt and landscape normally.
4. Non-engineer solution and hacky option: Find a below grade plastic membrane, dig up 6-12 inches of all the dirt, lay this whole membrane across and span the whole wall on the ground, slope it away from house. Backfill with dirt and landscape.

 

[cvg]

4th option
install a catch basin, connect it to the existing pipe and grade to drain into the catch basin

also, not sure how water is getting into the garage, there must be some gaps or cracks in the CMU where it can run through, maybe running behind the brick. is there flashing on top of the brick?

 

[oldestguy]

Hey, I see you have seen my posts on proper subdrain filter.
What would help us all is a simple sketch of the house layout as seen from the sky and show as much of the lot and neighboring lots as possible., Either add approximate contours or at least arrows showing flow direction of surface water. If possible use some shading or other way to show elevation of lowest floors.

How far out from the house would estimate there was excavation and backfill during house construction? Commonly that is disturbed ground that will "accept" inflow of water into the area of the house.

A cross section view of house and lot where you can show relative elevations and where water is found. etc.

On your plan view of the site show where downspouts drain to (such as 4 ft. out? 8 ft. out)?

With these details we likely can suggest what to do.

 

[andyl9063]

1. we fix the brick with flashing on top, double caulk inside and outside, then paint the flashing.
Better side picture attached. It is a pretty level and large lot so none affected by neighbors.
That ground spot where the brick is all sloped away from the house. I still don't understand how water is going down and coming into garage.
The fact that it comes into the garage AT THE BOTTOM of the CMU wall is the weird part. Because from the top grade where brick is 4 feet to the bottom of the garage.
Water is hitting the ground, draining, 3-4 feet and seep into the garage. It kinda baffle me.

I also want to mention the house was doing this prior to any renovation we did so we knew about the issue.

 

[oldestguy]

Missing the more detailed stuff I asked for.
However, explain just where are the roof gutter drains and the downspouts. I see none on the photos,but maybe they are old shots, right? The reason I asked for more details, sometimes they will help explain things and factors not known before.

 

[andyl9063]

Here you go. We upgraded to 6 in gutters just to be safe.

 

[oldestguy]

I'll throw in soothing from another post, to think about maybe.
oldestguy (Geotechnical)
8 Jan 20 16:37
In line with Mountain Climber. On way you can "waterproof" an area with that fine grained soil is to do some hand labor or easier with a roto tiller. Go to a distributor of well drilling products, such as a heavy hardware outlet. There you can get what they term "driller's mud". It is a dried natural clay called bentonite or montmorillonite. Be sure it is the powder variety, not granulated. Well Drillers use it mixed with water for keeping a the hole open while drilling. It is VERY expandible. Use too much in a mix with soil can cause problems. So experiment before dong much with it. Mix in to native soil maybe 3 to 5 pounds per cubic foot of natural soil. This mix will take on water and be practically impermeable. Too high a percentage mixed in will have a constant soft sloppy condition. A little goes a long ways. It is cheap, but don't over do it. When I have done this we strip off the sod and then work it into a soil layer about 3 or 4 inches with a roto tiller. Thorough mixing is required. Replace sod.

Do your experimenting with it by carefully measuring and use something like a kitchen sieve into which you put the mix. Dampen it and test how well it holds water. I'd do the test on a thin layer of soil, maybe 1 to 2 inches thick and have some way to get a "Head' of water on it. A tin can with fine holes punched in bottom might do it. Be precise with measuring. Maybe do the mixing test on site but only one or two square feet.

 

[oldestguy]

Looking at last shot, it seems there is higher ground on neighboring lots. Any area sloping situation can affect many lots. I've seen water dumps on ground next to buildings, but it migrates along foundation areas and can cause trouble far from where it enters grounds.

For instance is the living room floor the lowest floor there or is it over a crawl space? How does one know that water entering the ground at the rear of the house is not the culprit?

 

[andyl9063]

These are 1 acre lots so the neighbors don't really affect that spot. Not to the best of my knowledge or what I have seen.
The right size opposite of the brick is over a crawlspace, that doesn't get any water in. That side drain to back of the house.

It only affects below the brick area BUT only when it rains hard.

 

[GeoEnvGuy]

I looked at your second photo and it appears as though the drain pipe discharge is above the level of your garage floor. This would mean that you have ponded water in the gravel pack above your garage floor level pushing against the bricks.

 

[andyl9063]

Sorry, that was old pipe. We took it out. It's solid 4 in pvc pipe in the ground with holes right at the bottom of the garage floor or cmu wall.
It discharge out to the driveway.

 

[oldestguy]

Reason for wanting an area description is that there may well be a ground water situation that affects things. Are you absolutely sure that water on the ground surface in back does not soak in and follow the foundation all the way around to the garage foundation? Remember that once in the ground the only rule that water follows is the least resistance and where the "water table" is lower. What is the backfill like all around the house? Tight? loose and never compacted? My experience is that once in the ground (made from backfill to a house), water will flow diagonally down toward the foundation in the layers left by the machine pushing that backfill in. So water entering the ground many feet from a house more likely than not will get to the building wall via those loose layers laid that way.

This first showed to me was at a long apartment building,maybe 200 feet long, by 40 feet front to back. Water entered the ground at the south-west rear corner and first entered the basement at the north east front corner. Your water might now be coming from the rear corner area diagonally opposite the problem area. I highly question that your sub-drain is totally at fault.

Isn't that neighboring land beyond the opposite area from last photo somewhat higher? I can't believe your lots are absolutely flat with no sloping ground water possibilities.

In my experiences some strange things have come up, but the reason sometimes totally not predicted. Common for ground water problems. Your question at the garage wall might need a different explanation.

 

[Ekenny_G]

Looking at the photo, since this is a one acre lot, most of the contributing drainage is from the roof top. Since a gutter was installed with downspouts which disconnects the rooftop from contributing to any runoff. It will be prudent to check the french drain installation.
The french drain should have two or three courses of perforations and to be placed with the holes on the sides or top, NOT facing the bottom of the PVC pipe.
And it should be wrapped loosely with some cloth so as to prevent the holes from clogging sooner.

 

[oldestguy]

Ekened----: Your advice shows you have no experience with sub drains and plugging issues. Holes on the bottom minimize the "transport" of fines via the drains. That of course assumes the wrapping filer is done right. Frequently it is difficult to wrap drains properly. His use of single sized backfill is a mistake however. That is not a filter and it is very possible the mud came along via he voids of that rock fill and built up on his wrapping "filter' and plugged it . the least expensive and yet best working sub drains have small holes on the bottom, backfill with concrete fine aggregate sand and they work forever. DO NOT USE SINGLE SIZED STONE FOR THE BACKFILL. MIGHTAS WELL NOT USE ANY KIND OF BACKFILL AND RESULT WILL BE THE SAME--PLUGGING.

 

[Ekenny_G]

Oldestguy --: Having the holes facing the sides is as effective as facing down. I have seen it done either way and works forever. Its on a case by case depending on the issue. Based on the description of the issues, the french drained failed within a short time. Thats big RED FLAG for any "experienced" sub drain contractor or engineer. So the installation needs to be re-examined. Also, would likely need more holes drilled to ensure adequate collection and the last segment of the pipe can transition to solid pvc for distribution before it daylights.

 

[sina880]

you can also read in the site of civil thesis