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.
Joe
Chad Miller
Sep 26, 21 7:09 pm
Hire an architect or landscape architect . . .
b3tadine[sutures]
Sep 26, 21 8:23 pm
Two words;
Riprap
Gabion Walls
Three words;
Hire. A. Qualified Design Professional.
[okay 5ive, but maths aren't my strong suit]
Chad Miller
Sep 27, 21 2:35 pm
That's why we became architects - cuz maths be hard.
midlander
Sep 26, 21 9:36 pm
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.
Non Sequitur
Sep 26, 21 11:42 pm
Looks fine, just seal some of those joints with caulk and it'll be solid.
justavisual
Sep 27, 21 3:44 am
get a civil engineer and do what they say
Volunteer
Sep 27, 21 5:42 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.
Joe_B
Sep 27, 21 8:45 pm
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.
joe
rcz1001
Sep 27, 21 10:18 pm
.
rcz1001
Sep 27, 21 11:11 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.
b3tadine[sutures]
Feb 8, 22 10:24 am
Has anyone designed a gravel path, in a northern climate? What I'm looking for is something that can easily be maintained, and allow for ADA accessibility.
x-jla
Feb 8, 22 10:34 am
Use it alot in southern climate. 1/4” minus DG that’s compacted is used often in zoos and public gardens. It’s probably not suitable for a northern climate. For a northern climate, where you get more rain and erosion, I’d look into a stabilizing products like this and use a pea gravel for the paths…https://www.coregravel.ca/core-
foundations/core-gravel/
b3tadine[sutures]
Feb 8, 22 10:44 am
Cool! Thanks! The Walker Sculpture garden is open all year, and they have a great crushed gravel pathway system. Granite I think. So they'd need to maintain that for wheelchair accessibility.
x-jla
Feb 8, 22 12:17 pm
misspoke there…to be clear, you would not want to use a true pea gravel for ada. In my area it’s not available so it’s become a bad habit to call 1/4” crushed gravel pea gravel. You want to use a small crushed gravel. pea gravel is an alluvial material, and because of its rounded shape it will become displaced more easily. The angular crushed gravel will be more stable.
Everyday Architect
Feb 8, 22 2:52 pm
b3ta, our landscape architects have had trouble calling crushed gravel pathways as ADA compliant because of the requirement for firm and stable surfaces. Instead they have to look at binders to try to stabilize the gravel and that's apparently been difficult to get done well (probably more related to the installation rather than the products themselves).
We glued ours down. Slight color shift, but looks good and fit the ADA bill.
,,,,
Feb 8, 22 3:13 pm
Geoblock
,,,,
Feb 8, 22 3:27 pm
GEOBLOCK Key Applications
Emergency access lanes
Utility access lanes
Overflow parking areas
Road shoulders
Trails and trail-hardening
Pedestrian walkways and barrier-free ADA access ways
Golf cart path shoulders and aprons
High use areas & permeable load support
SneakyPete
Feb 8, 22 4:35 pm
My experience with grass pavers has been less than stellar.\
Chad Miller
Feb 8, 22 4:46 pm
DG with an emulsifier tends to work well in northern climates. Every 8-10 years you will have to spread a bit more DG and recompact / emulsify though.
lillianlambert
Apr 3, 22 9:20 am
I just got done building one for my backyard. I did more of a gabion-style wall with wire and stones on the inside. I did this style so that drainage and hydrostatic pressure wouldn't be a problem in the future. If you do bricks make sure to do some sort of drainpipe behind the wall. The effort level depends on if you get an excavator or not. I recommend digging 11-12 inches below your ground-level point for the wall and doing 3-4 feet above that. I also worked with some concrete contractors to make the backyard's sidewalk, and it all looks amazing.
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.
Joe
Hire an architect or landscape architect . . .
Two words;
Riprap
Gabion Walls
Three words;
Hire. A. Qualified Design Professional.
[okay 5ive, but maths aren't my strong suit]
That's why we became architects - cuz maths be hard.
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.
Looks fine, just seal some of those joints with caulk and it'll be solid.
get a civil engineer and do what they say
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.
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.
joe
.
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.
Has anyone designed a gravel path, in a northern climate? What I'm looking for is something that can easily be maintained, and allow for ADA accessibility.
Use it alot in southern climate. 1/4” minus DG that’s compacted is used often in zoos and public gardens. It’s probably not suitable for a northern climate. For a northern climate, where you get more rain and erosion, I’d look into a stabilizing products like this and use a pea gravel for the paths…https://www.coregravel.ca/core-
foundations/core-gravel/
Cool! Thanks! The Walker Sculpture garden is open all year, and they have a great crushed gravel pathway system. Granite I think. So they'd need to maintain that for wheelchair accessibility.
misspoke there…to be clear, you would not want to use a true pea gravel for ada. In my area it’s not available so it’s become a bad habit to call 1/4” crushed gravel pea gravel. You want to use a small crushed gravel. pea gravel is an alluvial material, and because of its rounded shape it will become displaced more easily. The angular crushed gravel will be more stable.
b3ta, our landscape architects have had trouble calling crushed gravel pathways as ADA compliant because of the requirement for firm and stable surfaces. Instead they have to look at binders to try to stabilize the gravel and that's apparently been difficult to get done well (probably more related to the installation rather than the products themselves).
https://www.access-board.gov/ada/guides/chapter-3-floor-and-ground-surfaces/#firmness-stability-and-slip-resistance
We glued ours down. Slight color shift, but looks good and fit the ADA bill.
Geoblock
GEOBLOCK Key Applications
Emergency access lanes
Utility access lanes
Overflow parking areas
Road shoulders
Trails and trail-hardening
Pedestrian walkways and barrier-free ADA access ways
Golf cart path shoulders and aprons
High use areas & permeable load support
My experience with grass pavers has been less than stellar.\
DG with an emulsifier tends to work well in northern climates. Every 8-10 years you will have to spread a bit more DG and recompact / emulsify though.
I just got done building one for my backyard. I did more of a gabion-style wall with wire and stones on the inside. I did this style so that drainage and hydrostatic pressure wouldn't be a problem in the future. If you do bricks make sure to do some sort of drainpipe behind the wall. The effort level depends on if you get an excavator or not. I recommend digging 11-12 inches below your ground-level point for the wall and doing 3-4 feet above that. I also worked with some concrete contractors to make the backyard's sidewalk, and it all looks amazing.