badly constructed wall

wall

wall

Hi we had a contractor terrace our yard and put in a dry stack wall. He used stone dust as a base and also as the drainage behind it. He used regular landscape fabric behind the stone dust, the kind you put down for weeds. We asked for drainage but it was not installed. Now when it rains we have extensive flooding in our back yard water streams out of this wall. The max height is 3 ft. We need to fix this and are going to rebulid it. We live near Charlotte NC the soil here is clay, we don't get severe frost. The question is on the fabric the woven polyproplyene fabric that you mention is this soil stabilization fabric, if so does'nt this get clogged up? Can we use the 4oz. drainage fabric that is sold for pipe drainage?Also we are perplexed on the stone behind the wall as we really need drainage that will collect water behind this wall before it hits our yard. Since the wall is natural rock and will be dry stacked where would the perf pipe be located in that it would enter the pipe instead of just running out between the stones. Also we now have tons of useless stone dust can this be used instead of the sand? Thanks M. Howgate

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Jun 18, 2015
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Cautious
by: Beca

Yeah, the gap between the stones can be seen clearly and it suggests that it was packed so loosely that it will sure collapse with a good rain. The stone in between is so small which makes it so weak.


Apr 10, 2015
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True information is shared
by: Tom R. Sledge

Just stumbled across your blog and was instantly amazed with all the useful information that is on it.







May 06, 2013
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Stone wall help
by: Anonymous

Thanks for the question.

Soil stabilization fabric is called geogrid. This is a type of fabric used in engineered walls that are usually over 3 ft. in height. (This depends on your local laws)

It is a method of "Locking" the retaining wall to the soil bank behind it, but shouldn't be needed in your case.

As far as the other landscaping fabrics are concerned, it depends on what purpose they are being used for.

The drainage that the contractor should have installed (Especially if you requested it) should be located in behind the base stones of the wall.

This drain pipe is usually protected by a landscape "sock" to keep it from getting clogged. This pipe will take the water away to another location during times of heavy rain and saturation.

The pipe is placed in behind the basestones. The forces of gravity on the water will force the water into the openings of the pipe.

This is what we call hydrostatic pressure.

You can still use a polypropylene fabric between the gravel back fill, and the soil bank. This will keep the soil from migrating into your drainage rock. This will allow more free flowing drainage.

This is typically done more in frost climates to keep the drain rock clean as soil will hold moisture and can lead to heaving.

For the time, effort, and cost, I use this woven polypropylene fabric, gravel back fill, and a drain pipe for most of my walls. There may be times when this isn't needed (smaller garden walls), but the cost of rebuilding a retaining wall usually outweights any overkill in construction.

(This is a personal choice).

If you have clay soil, there may be other options for you of controlling the water at the surface rather than rebuilding the wall.

One of a landscapers first considerations with any project should be controlling water at the surface.

It is acceptable for the wall to allow a certain amount of water to pass through, but it sounds like you have more than you need.

As far as the stone dust you have left over, is it possible to consider a feature up to the walls edge that could control heavy surface water? Perhaps a dry river bed lined with stone dust?

I would like to look at this more in depth if I can, but will require some more pictures of the area including the source of the water and the overall bigger picture if possible.

Please email me personally at kevin@dream-yard.com so I can respond.

Thanks again.

Kevin

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