Landscape Architect Advice (retaining walls)


Hello everyone,

I recently bought a place on a hillside in Tennessee.  The house and yard were completed in 1996.  In the attached images, the yard is sliding and the stone erosion barriers are failing.  I need to get some work done to remedy this. You can see that the stone barriers are pretty wide and if I had regular retaining walls installed to replace the stones it would cost a bundle.  I MUST have good drainage as eastern Tennessee has heavy rain most of the year.  So, between any new barrier I would need serious engineering around drainage integrated with the erosion solution.  I am going to have some other landscape work done and would like to address this issue at the same time.  

Was wondering if some of you experts might have ideas that would be more economical than installing new retaining walls, or whether newly installed walls with drainage is simply the right way to go.  I am currently renting the place so can't get anyone out there to give me estimates because I'd not be doing the work for 18 months until the renters move out.  So I wanted to do some homework, get some ideas and try to dial in some approaches I can ask the landscape companies who will bid on the job.  Would also be interested in the kinds of questions I should be asking.  

As an after thought, perhaps I can repurpose the existing stones, have them repositioned, etc. Would there be additional support I could integrate if I took that approach? Such as mesh lining and small posts every 10 feet or so.

Much appreciated.


Sep 26, 21 2:24 pm

Hire an architect or landscape architect . . . 

Sep 26, 21 7:09 pm  · 
1  · 

Two words;


Gabion Walls

Three words;

Hire. A. Qualified Design Professional.

[okay 5ive, but maths aren't my strong suit]

Sep 26, 21 8:23 pm  · 
2  · 

That's why we became architects - cuz maths be hard.

Sep 27, 21 2:35 pm  · 
1  · 

my first worry looking at this would be whether the ground is unstable enough to risk damage to the house and foundations. i'd recommend having a civil engineer take a look at the site actually.

Sep 26, 21 9:36 pm  · 
2  · 
Non Sequitur

Looks fine, just seal some of those joints with caulk and it'll be solid.

Sep 26, 21 11:42 pm  · 

get a civil engineer and do what they say

Sep 27, 21 3:44 am  · 

Over in nearby Asheville whole 'exclusive' developments are sliding down mountainsides at measurable rates a year. Not infrequently, the whole mountainside breaks loose and caries homes with it. There is no homeowner's insurance against slides. I would get a civil engineering firm experienced in the issue and follow their advice explicitly. In fact, get several opinions, and do so now.  

Sep 27, 21 5:42 am  · 

Thanks for the replies.  We did have two civil engineers inspect the place last year, specifically to look at the foundation.  There are some things we need to do with drainage that we will be doing in the not too distant future, such as rerouting the drainage. The foundation itself is fine and has no signs of cracking or sliding.  The soil in the back yard is soft because they dumped or mixed mulch into the dirt.  When it rains that mulch gets heavy when it soaks in the water and over 26 years its slid.  Appreciate the feedback.


Sep 27, 21 8:45 pm  · 
1  · 


Sep 27, 21 10:18 pm  · 

The photos indicates a hillside, I recommend a geotechnical engineer not just a civil engineer. The geotechnical engineer is required to study the geological profile of the soil not just within 5-feet of surface or whatever the depth of footings but they may do a deeper study to see if there is a slide issue at depths a little deeper than a standard shallow pit test. Pit tests are normally done to depth of typical foundations. If there is any geological studies done in the past in near by locations within 1000 ft. of the home... so figure a radius of 1200 to 1500 ft. from the center of the house. If there is any geological studies that includes bore tests anywhere near by within that distance, it would be worth getting a copy of those reports. A proper retaining wall (if you are going to install one) needs to be properly engineered and that will need geotechnical studies because even the greatest retaining wall isn't going to do squat if the ground underneath the retaining walls slides out. 

I don't see an imminent slide risk at the moment but that doesn't mean there isn't one that is not discernable yet in the photos. I see potential issues that would compromise your retaining wall due to issues like the ground moisture issues that you mentioned. You have drainage issues but that may not be the only issue. I'm not a geotechnical engineer. I am a building designer. 

In my locale, slide issues are very real issues and I have seen effects from past landslides in my locality. I would require a geotechnical study or immediately assume a landslide risk based on known slide areas and have some idea of geological profile of where I am. I recommend consulting a geotechnical engineer that is familiar with landslide and hillsides.

A civil engineer is still a recommended professional for the design of anything like retaining walls. On hillsides, erosion management issues are something you consult a civil engineer, not a landscape architect. Although, you may consult a landscape architect or landscape designer for landscaping designing but they need to coordinate their work with that of the civil engineer & geotechnical engineer, and work as a team for a design and engineering solutions. Do not cheap skate on this.

Sep 27, 21 11:11 pm  · 

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