Who knows about stacked-block retaining walls?

[wilso]

Yeah, it is definitely better to think everything over beforehand and find qualified and experienced specialists to avoid mistakes and consequences in the future. I’ve been checking out contractors on buildzoom. Really helpful for comparing credentials and reviews before hiring someone for retaining wall projects. Better safe than sorry with structural work.

 

[AnotherBueller]

Several location on my (steep) land are 'fills' that have been here since ?1960s? and they are still OK. They don't move.
And they have no geotextile reinforcement.
I have some other areas that I have filled even 12 feet thick, simply dumping the dirt over the slope. Areas where there's no consequence to soil slippage. They are firming up, not moving.
There's no water source above, and no earthquakes (yet).

I don't think many have a concept of how substantial geotextile reinforcement is.
A lot of folks understand "roots".
Geotextile is like permanent, horizontal roots, but much stronger because it's 2-axis. And it doesn't die then decompose.

The "foot" of my geotextile layup is near the base of the slope, so there's nowhere for this layup 'to go'.

View attachment 2664360
Here is a quick sketch.
I expect the topsoil to completely cover the (sand) lifts and protect them from erosion.
I do not expect enough water to erode anything.
In April, vegetation will grow with a vengeance.

Around here soil that has been undisturbed for 40+ yrs is considered stable for building.

 

[RayIN]

12 years ago I had a landscaping company build 2 such retaining walls. One is 5' high X 18' long the other only 2' high x 10' long; it is above the 20' wall. Neither has a drain or crushed stone behind them, only dirt. The only thing that' happened is, the 2' high wall sank about 1" in the center.

 

[LouNY]

12 years ago I had a landscaping company build 2 such retaining walls. One is 5' high X 18' long the other only 2' high x 10' long; it is above the 20' wall. Neither has a drain or crushed stone behind them, only dirt. The only thing that' happened is, the 2' high wall sank about 1" in the center.

Do you get wet ground freezing and frost heaves?

 

[RayIN]

LouNY_ yes. The landscape company accepted the job in July, didn't show up until after Jan 1. DW was ill so I didn't concern myself with the walls. MY BAD!
Had I been thinking, I'd have told them forget the job and hired a different company that following spring.
I don't care who or how, disturbed dirt cannot be compacted in a few days like it was before being moved.
It's said we never stop learning, I'm proof.
Spoke with a different company last year. The owner said he can repair it easily. He uses the same technique as lifting a concrete patio to level.

 

[fishdoggy]

The T posts and welded rebar have taken this all up a notch, all this for a rental says a lot about the landlord !

 

[yanmars]

I live in western Ohio. Almost every stacked wall even if only a few block high have pushed out or over after 5 to 10 years. Some were done by home owners, some not. Not sure what prep they did before laying the same.
I see dry stacked walls in Columbus that have stood properly for over 50 years. I guess how they are done.

 

[Sodo]

View attachment 2651749
I made this image with photoshop from an install doc posted by airbiscuit.

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  block wall diagram.jpg

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July 2025 project status in case anyone's still interested .

here's the two wall drains
1.25" drain at the bottom, and the 3" corrugated at the 3rd course.

Not even "one drip" has exited either pipe since installation in January.
Each pipe has "original dust" in its end.

But someday, when the gravel drains fill with silt, the open pipes may begin to carry water out.

Oooops sorry - this pic was long before the geotex layup.
Here's the driveway + roof downspout drain.
And the perforated pipe at the house foundation.

You can see where I cut the stairway, just past the center supports. Adding a landing.
The cut part of the stairway continues (at right) sitting on the (new) concrete retaining wall.
That little 'whoopee' in the wall end will get buried, luckily.
Its from using USB as form-board. It softens when wet.

Backfilling wall with drain gravel

Here is today, (6 months later, summertime).
I'll put those large permeable tiles to park on, and grass seed.

Enhanced pic with 'green-line' added by photoshop

Hope you enjoyed the project. I definitely enjoyed the chatter.
Much of the TBN assistance was used, and I'm positive I ended up with a better finish,
so THANK YOU ALL!

I'll measure & document summertime heights of the wall-tops,
.....then measure again after winter 2025 & report back.

 

[Sodo]

The T posts and welded rebar have taken this all up a notch, all this for a rental says a lot about the landlor

Any project worth doing - is worth overdoing when DIY.
especially if you have extra time
and the tools
and the inclination....

I live in western Ohio. Almost every stacked wall even if only a few block high have pushed out or over after 5 to 10 years. Some were done by home owners, some not. Not sure what prep they did before laying the same.
I see dry stacked walls in Columbus that have stood properly for over 50 years. I guess how they are done.

Yes there's prep, and also the stability of the existing terrain.

 

[2manyrocks]

Anything you would do differently or could have saved some work looking back?

 

[newbury]

Any project worth doing - is worth overdoing when DIY.
especially if you have extra time
and the tools
and the inclination....

Well you certainly have the inclination, darn near vertical

 

[EddieWalker]

Thanks for the update. It's been a fun project to watch. I have to admit that it's been a bit overwhelming seeing all that you did, and it got me to rethinking plans for my place.

I've been planning on building a short retaining wall for my drainage ditch that goes through my yard but haven't found any blocks that I really like the look of. Now I'm going to just remove all the dirt and plant grass so I can mow it. More work on the tractor, less money buying materials, and a totally different look.

 

[LouNY]

Thanks for the update. It's been a fun project to watch. I have to admit that it's been a bit overwhelming seeing all that you did, and it got me to rethinking plans for my place.

I've been planning on building a short retaining wall for my drainage ditch that goes through my yard but haven't found any blocks that I really like the look of. Now I'm going to just remove all the dirt and plant grass so I can mow it. More work on the tractor, less money buying materials, and a totally different look.

Sod waterways are the best way to go when possible.

 

[lilranch2001]

I have a 300 foot sod waterway in my yard that drains the neighboring Farmfield. in 2010 I had to redo it because of all the silt had filled in it, it had become marshy.
I redid where the water runs onto my property so that it doesn’t run quite so fast and now it has held up for 15 years pretty well without silting

 

[Sodo]

Anything you would do differently or could have saved some work looking back?

I would have liked to have a real "compactor". But you can't have every piece of eqpt that you wish for just hanging around. DIY can take months.
Finding a trucker to bring me SAND for fill, that concern reduced somewhat. (Free sand !, a little bit moist. and LOTS of it !)

Wish I had a 3rd pic (of the geotex folded over ontop.)

Tracked vehicle doesn't compact much, but it's moist sand, and its heavy.
I suppose it's weight compacts all the lift layers below.
Those form boards are 4x12 held vertical with #5 rebar stakes into the geotex lift below.

I have laser elevations "before", and will be able to measure settling of the top surface as time passes.

What I most needed, and wasn't able to get, was confirmation that a stacked block wall leaning against a Geotex retaining wall was..... "no worries of soil pressure against the block wall".
(re: Civil Engineer member Sam Wise, see post Who knows about stacked-block retaining walls?) who wrote that the stacked block wall was a decorative facing for the (geotextile) retaining wall.
If that's the case.....
and I tend to believe it
then there's almost no pressure on my stacked blocks.

Anyway, I had to press on, with advice from just one TBN engineer who told me what I wanted to hear and of course it was a sweet sound...

Any more civil engineers willing to opine......?
Is the block wall subject to soil pressure from the geotextile reinforced embankment?

The 5/8clean gravel and the topsoil heap doesn't look like 'much'.
The block mfr approves 42" max (without reinforcement).