Hi all, I'm currently designing a project where our client would like 2 30" tall berms on either side of their exterior patio, similar to the attached image. We are working with a structural consultant who only has experience with overall slope stability, not berms.
Is it possible to build something like this (in Texas) where only one side of the berm has a retaining wall and the other slopes like the image?
Problem with grass slopes is maintainence. I would go with a groundcover like myoporum parvifolium or trailing rosemary if suitable for your area of TX.
I don't see why not. 30" is nothing extreme. Just keep the slope 25% max to reduce erosion and should be ok. If covered with vegetation like grass or ground cover plants rather than gravel it will be more stable as the roots will help stabilize the soil (probably more important if you are in a heavy rain area of TX). Doubt it will even require a permit if 30" or below, but double check local req.
The structural engineer should design the retaining wall to ensure it does not tilt or settle. Earth is surprisingly heavy. As for the berm itself the problems of erosion are mostly resolved in the planting. I have used a plant here in Chicago to mitigate erosion on the side of a railroad embankment 45-50 degree slope called Irish Moss. It is not a moss but a low growing green ground cover that has a look of fine moss does well in sunlight but is not very drought tolerant. The key thing with the berms is to ensure the soil used to build it up is evenly compacted and is free from organic debris that might rot and lead to settling. If erosion is a concern you can use plastic edging in even rows perpendicular to the slope to help hold soil in place wile seeded grass gets established. Sod is sometimes a good way to go but the slope could be tricky and requires careful watering so that the top stays wet and the bottom of the slope does not get too soggy and suffers from root rot.
Hope you can post photos once you get this project done.
Over and OUT
Peter N
Jan 24, 18 12:02 pm ·
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Featured Comment
x-jla
Problem with grass slopes is maintainence. I would go with a groundcover like myoporum parvifolium or trailing rosemary if suitable for your area of TX.
Jan 24, 18 12:07 pm ·
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x-jla
and specific lighting conditions of the area...
Jan 24, 18 12:08 pm ·
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x-jla
Grass is doable, but kind of a pain in the butt to cut on steep berms.
A retaining wall should be within the scope of knowledge and abilities of a capable licensed architect. This case as described is not too onerous or extreme. But seeking advice when you are unsure of your abilities is good practice.
Jan 24, 18 12:20 pm ·
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x-jla
Where I live only an engineer can submit plans for retaining walls. Most contractors use standard details over and over and build these things all day long. In most places, only if the wall is over 36" to the footing will a permit even be required. The berm itself can be built by a dog, 3 yo child, or a trained monkey. It's just full dirt lightly compacted. Usually 3/4" minus fill.
Read the last sentence of the original post the berm will cover one side of a low wall. They have a patio that the berm/wall will surround. The wall and berm I assume are above the surface of the patio floor.
Thanks, but I am still confused as to which side of the berm will face the patio. The photo seems to indicate the grassy side of the berm would face the patio?
Building a Berm
Hi all, I'm currently designing a project where our client would like 2 30" tall berms on either side of their exterior patio, similar to the attached image. We are working with a structural consultant who only has experience with overall slope stability, not berms.
Is it possible to build something like this (in Texas) where only one side of the berm has a retaining wall and the other slopes like the image?
2 Featured Comments
Throw some Typar Geocell GS - Slope Stabilization or similar at it
Problem with grass slopes is maintainence. I would go with a groundcover like myoporum parvifolium or trailing rosemary if suitable for your area of TX.
All 7 Comments
Hire a landscape architect. Don't ask a structural p.eng about a 30" ant-hill.
I don't see why not. 30" is nothing extreme. Just keep the slope 25% max to reduce erosion and should be ok. If covered with vegetation like grass or ground cover plants rather than gravel it will be more stable as the roots will help stabilize the soil (probably more important if you are in a heavy rain area of TX). Doubt it will even require a permit if 30" or below, but double check local req.
The structural engineer should design the retaining wall to ensure it does not tilt or settle. Earth is surprisingly heavy. As for the berm itself the problems of erosion are mostly resolved in the planting. I have used a plant here in Chicago to mitigate erosion on the side of a railroad embankment 45-50 degree slope called Irish Moss. It is not a moss but a low growing green ground cover that has a look of fine moss does well in sunlight but is not very drought tolerant. The key thing with the berms is to ensure the soil used to build it up is evenly compacted and is free from organic debris that might rot and lead to settling. If erosion is a concern you can use plastic edging in even rows perpendicular to the slope to help hold soil in place wile seeded grass gets established. Sod is sometimes a good way to go but the slope could be tricky and requires careful watering so that the top stays wet and the bottom of the slope does not get too soggy and suffers from root rot.
Hope you can post photos once you get this project done.
Over and OUT
Peter N
Problem with grass slopes is maintainence. I would go with a groundcover like myoporum parvifolium or trailing rosemary if suitable for your area of TX.
and specific lighting conditions of the area...
Grass is doable, but kind of a pain in the butt to cut on steep berms.
Some nicely constructed gabions would probably look better, in scale, than a block retaining wall.
You need a geotechnical engineer/report, and a civil engineer or LA to do the berm.
A retaining wall should be within the scope of knowledge and abilities of a capable licensed architect. This case as described is not too onerous or extreme. But seeking advice when you are unsure of your abilities is good practice.
Where I live only an engineer can submit plans for retaining walls. Most contractors use standard details over and over and build these things all day long. In most places, only if the wall is over 36" to the footing will a permit even be required. The berm itself can be built by a dog, 3 yo child, or a trained monkey. It's just full dirt lightly compacted. Usually 3/4" minus fill.
Why would you need a wall at all if a cross section of the berm is symmetrical?
Read the last sentence of the original post the berm will cover one side of a low wall. They have a patio that the berm/wall will surround. The wall and berm I assume are above the surface of the patio floor.
Thanks, but I am still confused as to which side of the berm will face the patio. The photo seems to indicate the grassy side of the berm would face the patio?
That is unclear from the post. good question.
I assumed the grassy side faces the owner and they're giving everyone else the finger with the ugly ass retaining wall.
Throw some Typar Geocell GS - Slope Stabilization or similar at it
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