Obviously the weep holes are clogged. Water is doing the damage but it could also be the roots of nearby plantings which are pushing against the one wall. You might want to dig down along the top of the wall and find those roots and cut them back along with cutting the top of the plant back. Generally roots reach out to the drip line and beyond. The weep holes aren't draining because the soil settled into the gravel behind the wall clogging up the drainage. You might want to replace some of the soil with gravel. It is a lot of detail work, it won't get done in a hour but you'll be charged big bucks if you hire it out.

Here is a link that might be useful: Propagating Perennials

"I am looking for a way to prevent further deterioration ..."

Remedial work on the wall can be divided into two types; those actions that reduce the load on the wall and those things that can be done to strengthen the wall. The things that come to mind are (1)drainage enhancement (weep holes, backfill changes, upper wall grading) and (2)reenforcement (block cavity fills, counterforts, buttress, and footing cleats.

The only weep holes I see in the photo show the holes to be well up on the wall. You might drill new holes near the bottom of the wall. You would also find if the block cavities were filled with concrete. Drainage would also be improved if postholes were dug behind the wall to intersect the new weep holes: backfill with a mix of sand and pea gravel.

Without knowing a lot more about the situation it's hard to say what other remediation might be practicable.

Any chance this would work?

Drill new weep holes at bottom of wall, fix filter fabric to one open end of the pvc pipe, slide pvc pipe through wall with filter side into the earth.

{{gwi:9025}}

If the block cavities were filled with concrete then you will have a hole through solid concrete and the pvc pipe is not needed. Probably a good idea to seal the inside of the hole with a bit of block bond. After the seal cures, stuff a small wad of filter in the hole and use a rod to drive it out the backside. Repeat a time or two then leave the last filter inside the hole.

If the cavities were not filled then I would stop after the first hole and reassess the situation.

The block cavities are hollow.

Do you think the filter fabric is enough to keep the holes clear and water flowing?

My concern with this solution is that the existing weep holes are clear all the way through the wall and to the other side. I can push a rod all the way through without hitting dirt. For some reason the water still does not flow through them. I'm assuming there are no pebbles on the backside of the wall to aid in water flow. But digging the wall out completely would be almost impossible for me.

I was also thinking of something like this as a solution:
http://www.thisoldhouse.com/question/drain

The "thisoldhouse" has the same suggestion I made in my first post. Both of us failed to say that the last foot of backfill to the post holes should be compacted soil, not a porous substance.

But the truth is that if the block cavities are hollow then the wall is going to fail, no matter what you do about the weep holes.

But digging the wall out completely would be almost impossible for me.

When the wall falls downs, somebody will dig it out. There is not going to be a $100 fix for this wall and there are few contractors that will take remedial wall work.

I may be very off base with these thoughts. Just working with one of my hunches. Looking at the sloping land behind the walls which should aid in moving water away from the walls, plus the statement that the weep holes appear to be open and the concrete block cavities are hollow...it is my guess that the walls have been painted with a waterproofing concrete paint which has sealed everything and the wall is not able to breathe. The usual fix for this situation on waterproofed interior cellar walls is to bang a small weep hole in every block ( hollow part) along the wall base which allows the wall to drain into a gutter leading to a sump pump. Go along the wall and tap in a five or so weep holes right along the base to see if water begins to drain. I think it will.

Nandina: You are correct, these walls were covered with Drylok and then painted two years ago. I understand how that could seal in moisture, but why that would prevent the existing weep holes from flowing? And could it weaken the wall to drill more weep holes when the blocks are hollow? Thanks.

pls8xx: I know that these walls will need to be replaced. My goal is to delay the speed at which they deteriorate, not to stop them from deteriorating. Whatever additional time I get will allow me to save for new walls.

{{gwi:9027}}
{{gwi:9028}}

I'm sorry if I sound a little harsh. Some have said to post on this forum is to invite a beating. But most of the regulars here are really trying to be helpful. The guy that built your wall was kidding himself that it would last. If I seem harsh it's because I'm trying to get you to see the reality of the situation.

Based on what I you have said to now, I now believe that the wall failure is not so much a water problem as it is the mass of soil retained. It's not clear whether the wall could be saved. By saved I mean an extended life of 25 years plus.

For all I know, you may have a distaste for the look of that wall that would justify it's replacement. I often take a DIY approach to projects because I always have some other place I want to spend my money.

One aspect you might consider is that the wall is tall enough that in many locations a new wall would need an engineer's involvement, plans, and permits, which might not be needed for a repair of the existing wall.

The wall might last for years, but it could fail this year. If it fails during winter, can you just leave it be until the following summer? Rebuilding in the winter could double the cost.

I don't think that additional weeping is going to happen. The problem is that the wall is simply not strong enough to last over time. Time has moved forward and continues to tick.

Water won't come out of a weep hole until the soil can not hold it any longer - saturation. The tighter the soil, the more it clings to water and the more it weighs. Without removing soil from behind that wall and replacing it with soil (or gravel) that won't load with water, you can drill as many holes as you want and the water won't come out until that soil is loaded. The gravel won't load because it will not draw water out of the adjacent soil until that soil is saturated. At saturation, water movement is driven by gravity alone rather than capilary movement, so the water will go to the bottom of the gravel and come out of the first weep holes it encounters as the water rises.

None of us knows how these walls were constructed or tied into the bank. What you have been given are 'experiences and observations' of failed retaining walls and usually we find out why a wall failed when it is taken apart. The expensive school of hard knocks!

My thought, based on waterproofing concrete block, makes me wonder if pounding a nail size weep hole into the hollow block sections at the base of the wall will indicate a water build-up. The weep hole would not be through the entire block, just the outside wall. That is why I suggest trying five or so weep holes to see if any water drains out which would indicate that this is part of the problem...of which all of the above could also be a part of the puzzle.

jb nj,

I have the same type situation. As I do not want to spend $5k on replacing a 3' high by 15' wall this year, I am thinking of other options.

As much as I am against the modular block walls, I will say, they are easier to install on a DIY basis. A cinder block wall in my area requires a 3' deep footing, and I know I do want to dig that out myself. Plus there is the puring of concrete and the mortaring of the wall, etc. So $5k is worth it for that type work, I just don't have the money.

From what I have read, modular block only requires a 1' to 1' and a half footing and there is no mortar required, meaning, no drilling of block for weepholes, etc. The hard part is putting enough drainage rock behind the wall, which means more excavating. Plus, I can DIY it with a couple of buddies over the course of a weekend.

So those are my options right now, I am leaning towards the modular block right now. Now I just have to find one I like.

Good luck, and think it out.

nandina: Thanks for your input. But I am still not sure why you think nail-sized holes in the exterior block wall would drain. If the larger weep holes at the bottom of the walls do not drain, why would these?

pls8xx: Again, I am NOT trying to save the walls. I am trying to get another 1-3 years out of them before they have to replaced. There's a big difference there. Even an incremental delay in their deterioration would be a success, so "bandaid" approaches like additional weepholes are fine in this context.

Re: surface drainage, I might be useful to put a trench drain in the earth above each wall to divert some water away from them and take some of that pressure off. But I do not have anywhere to drain them to. Would a sump pit work for this? Any other thoughts?

Here is the trench drain concept, I have several on my property:
http://www.askthebuilder.com/175_Drying_Soggy_Soil_-_A_Simple_Trench_Drain

In my opinion the easiest and most effective way to reduce stress on this wall is to dig a trench down to the first set of weep holes making them the low points in the trench (since you don't want to go all the way down). The wider the trench, the better. Line the soil side of the trench with silt fabric and fill the trench with clear drain rock all the way up to the surface.

Surface water will enter the stone and come out of the weep holes. The stone won't load with water (because the space between the stones is too big) resulting in the top half of the wall not being surcharged by heavy wet soil.

You can drill all the holes you want at the bottom of that wall. The only water that will come out is the excess after the soil is completely saturated. Then you will still have nearly fully saturated soil acting against that wall until it dries out.

There is a common misconception that sand and/or gravel removes water from soil. It does not. It does allow water to pass through it without holding it, though. That means that if you replace soil that does load with water with sand or gravel that does not, it will result in less pressure on the wall.

Showing my ignorance, but if and when the walls fail, instead of replacing them with the same kind of structure even though new and improved and correct - particularly wall #2- would terracing work? Like maybe two levels with drainage concerns addressed so neither level would be holding back the full force of the yard?

Where does water routinely drain away from your property? Is that gutter pipe in the wall #1 picture attached directly to storm water runoff drains or, heaven forbid, the sanitary sewer system?

I have decided I am going to try the "This Old House" drainage idea that pls8xx and duluthinbloomz4 suggested on one of the higher weep holes and see how it goes.

I appreciate all the input from this group; it has saved me a lot of wasted time and effort. I will report back on how this works out.

laag: I thought you were recommending the posthole method? Are you saying it is not worth the effort?

>The water has to be flowing on the surface and directed directly into those columns of stone for that to happen.

It is not just water running literally on the surface that will be drained. The top weep holes are down about 2.5'. The wall is at the bottom of a hill. Water moving down from the surface to about 2.5' of earth where the columns are will be drained. That doesn't seem insignificant.

>can help divert a certain amount of surface water out of the area before it has a chance to be absorbed by the soil

So isn't this better than doing nothing, which is my only option at the moment?

Another idea, which I mentioned already, is to dig a simple trench drain about 2.5" deep in the earth on the hill above the wall. It could run parallel to the wall for the length of the wall and be placed many feet back from it. The idea would be to reduce the amount of water running down the hill from sinking deeper into the earth and eventually putting pressure on the wall, especially the lower parts.

I'll try one more time. The soil behind the wall absorbs water, either from surrounding soil or from the surface. It loads up and gets heavier. If you leave it there, it will still load with water even with clear drain holes and columns of stone going down to them.

If you remove soil from behind the wall and replace it with drain rock, it can't load with water because the pores between the stones are too big. Ideally, you would replace it all the way down to the bottom for the full length of the wall and to the bottom weep holes. You indicated that you do not want to do that, so the next best option is to remove and replace as much as you can.

If there is actual saturation (which I doubt), the stone will fill with water. That is the point of the weep holes - to allow an escape for free water (not for water absorbed in soil). Free water flows by gravity as opposed to absorbed water which is sucked up by capillary action which has to do with surface tension of water and pore size the same way a sponge works. That is why I recommend replacing the soil down to at least that higher level of weep holes, just in case it ever does saturate it can escape. (or if surface water runs down the back of the wall from up top)

If that is too far to dig, I'd suggest just digging out as much as you are comfortable doing and replace it with drain rock.

Put silt cloth or weed fabric between the back of the trench and stone to keep the soil from infilling the voids between the rocks.

I'm hoping this makes sense because I tend to make simple things hard to understand sometimes.

It is simple. Drain rock weighs less than wet soil. That is all you need to know.

.... and those other methods will not dry out your soil.

I know rebar is sometimes used in these walls... do you know if it was used here, and if not is there any chance of adding some, or strengthening the wall with concrete put into the blocks or behind them (there's that digging work again!)?

KarinL

jb,

Do you know how deep that footer is on that wall? Since we are in the same region, the minimum depth for a footer for a cinder block wall in my area is three feet, so you will probably be about the same. If it is less than three feet down, your walls likelihood for failure will drastically increase so it will not matter what you do behind it.

I'd hate to see you do all that work for the drainage behind the wall and then have the foundation under mine the wall.

Good luck.

I don't know if the wall has rebar or what the footer depth is. I purchased my home with the walls as is.

The terracing idea is intriguing as a long-term solution. I just have to be careful about moving this much earth next to my house. Who would I contact to find out if that is feasible? An engineer or landscaping firm?

jb, from looking at your pics, rather than digging out the dirt to create the terrace, couldn't you come outward and use the space in front of the wall? Have dirt delivered and placed there after you build the form of the terrace? Not sure if you have to take down the wall though. Just a thought.