Retaining Wall and Fencing

by Dave G.
(Washington, DC)

I've got a rather unattractive slightly sloped retaining wall up against one side of my back yard. We are on the low side of the wall. The previous owners of the house attempted to fence in the backyard. They basically installed the fence right in front of the wall (basically flush with the base of the wall).

The problem is the fence was poorly built and is falling apart. It also seems that water drainage off the retaining wall has washed away much of the ground at the base of the wall and has weakened the foundation for the fence. I don't believe the posts were anchored properly in the first place. It has basically fallen and is now just leaning up against the wall.

It is my intention to tear down the entire fence and build up a new one. My concern is how can I properly anchor the posts at the bottom of this wall without having to worry about water drainage washing away the foundation? Even if I set them in concrete, the dirt around them could be washed away leading to the same situation.

On that note I do feel that having a fence against the wall is unsightly. Setting the fence away from the wall a few feet could solve the problem but would effectively cut down on the size of my back yard. It's a very small area in the first place.

I thought of possibly not fencing that one side of the yard and trying to incorporate the retaining wall into my landscaping but as I said it is very unattractive. I also would not be able to attach my fence to the wall since the high side and area surrounding it is "community property". This would leave a space between my fence and the wall that any kid who is feeling adventurous could climb between and get into our yard. Obviously some creative planning is needed here and I could use all the help I can get.



ANSWER
Hi Dave,

From your description, I believe I understand the positioning of the fence and the wall and your problems.

My first question would be, are you considering putting up a new fence to hide the wall or because you actually want the fencing for privacy and/or enclosure?

If you want a fence just to hide the wall, you can hide any wall with plantings so that you never even see it. The plants you would use would depend on how high the wall is, what the sun conditions are, if you have a deer problem, etc.

If you want to give me that information, I could give you some suggestions.

Installing a new fence is another matter (if you actually want the fence). The drainage problem might be caused by a few different things. It might be that the land is totally flat and the water has nowhere to go. It also might be that the land on the high side of the wall is very steep and causing a large amount of water to seep into the wall.

Drainage problems can be rectified, depending on what the situation is. For example, if the land is flat and the water is not draining anywhere, you might be able to re-grade it so that the water flows away. If there is a huge amount of water coming from the top of the wall, drains at the top of the wall (if this is your property or you could get permission) might be the answer.

Another solution to the water compromising the fencing is to install perforated pipe at the bottom of the wall, pitch it lengthwise, and lead it to another area. This method would bring the water away and alleviate the problem of sitting water. Your existing conditions would have to be known before an accurate solution could be suggested.

One other thing I'll mention is the make up of your soil where the fence is. Sandy soil will make the water seep into the ground more easily than if you have a clay-like soil.

Please let me know if you need more input.

Thanks,
Susan