Retaining Wall

Hello experts and not so experts. I need some advice on building a retaining wall. Now that my fencing project is done, I'm moving on to bigger and better/worse things!

When I had my house built, I had the builder dig out part of the he hill and push my house back into it. It's mostly rock and caliche so I knew I would have plenty of time to save and plan out a nice retaining wall, before it would erode much. Of course I am always trying to do things myself to save a buck and I've probably got myself into a hell of a project. It's been 3 years and hasn't changed much, but it's time.

So the wall I need to build is approximately 70 ft long and as high as 8-9 ft in one section and roughly 5-6 feet for the rest. I don't want to use railroad ties or anything like that. I'm planning some sort of stone, precast or something like that.

If I have to rent machines, I can run them and if I need to lay 12 inch stones one at a time, I can do it.

Could anyone tell me the most cost effective way to go about this? I want to spend the money once and not have to mess with the wall again. Thanks!

 

Hopefully @Notachickmagnet will chime in, Denise just built one.

 

Yes, I'll be grateful for any and all advice

 

https://www.versa-lok.com/

Good product. Easy to install. You can also redo if you need to or don’t like because they interlock with a pin. No adhesive or mortar needed. Can look at youtube videos if you want to check it out.

 

Thanks!

 

These are 16" blocks with a 4" cap. I recommend filling the cavities with crushed concrete. I used adhesive on the caps.
Before the first layer was layed we put down road base for the base.

 

Ok, so road base first. Does it matter how much base vs height/weight of the wall?

You are talking about the cavities better the wall and the dirt it's holding up, right?

How did you attach each block? Mortar or pinned?

Thanks

 

Being a home builder the past 45 years...
the best advise I have for you is...
seek the advice of an engineer for retaining walls that high.

opt- 1 ...stone rockery..
your maxed out at 4' without engineering.
A 4' rockery base course needs to be 3 to 4 man rock.
For an 8' rockery the base will require 5 to 6 man rock.
It's not likely someone is going to rent you their specialized equipment for this work

opt 2- Precast... Block walls are not advisable for that height.
they are maxed out at 30" to 36" without engineering & without special fill requirements & geo-tech fabric.

The 2 options you mentioned are for simple erosion control & are not retaining walls. These will likely fail if not done properly or enough moisture is introduced.

your best option is an engineered poured concrete "Retaining Wall."

I am currently building this type of wall 9' Tall at one of my jobs.
The retaining wall is 10" thick with #5 rebar.
The vertical rebar is placed every 4" bent into a 6' spread footing.
The horizontal # 5 rebar is placed at 8" spacing.
The spread footing is # 5 bar at a 4" grid.

The concrete must be poured continuous (no stopping or waiting for trucks) & vibrated throughout the pour to eliminate rock pockets.

hope this helps..

..Slayer

 

You would need to look at your local code for that one. For my wall I went with 4in deep for RB 20 inches wide. I'm sure ht and wt has a lot to do with it.

I have a friend who owns a landscaping business. He told me and helped me with everything.

Yes the cavities. Because I'm right under the required ht I did not require anchors. Again check your local codes.

After the second row I used adhesive just because it made me feel better. The blocks are keyed, they have grooves that lock to each other.

 

Definitely doesn't sound like a diy... have any pictures of what that ends up looking like?

 

Gotcha. Makes sense. I live in the country so no city code for me however I do want to do it right.

 

I have to play by county and city where I live.

 

I thought I read somewhere that if you purchase from this company they come out and give you an engineered plan for free.

 

@Slayer said exactly what I would recommend too, 4' max w/o engineering. I'll be doing an extensive project, very similar this summer but will step the terrain to keep w/in the 4' max. Don't forget, you need drainage behind a wall, especially with the height your talking about. A wall 8-9', done incorrectly can be far more dangerous than no wall.

 

Thanks. Im definitely going to make sure I have all the information I need before I start. I may get a contractor to give me a quote before I start to make sure it's worth doing myself. But I'm sure it will be astronomical if I have someone do it.

 

Hey Bud,
If your still thinking about rocks or blocks or even a poured wall.. those materials need to be placed on firm & un-yielding soil. (undisturbed).

You need to be careful about stepping back in a tiered wall.

unless it's engineered.. a typically a tiered system is stepped back twice the width from the height.
Example, if the 1st tier 4' tall the next tier should be 8' back.

Unfortunately, it sounds like to me, your builder carved out the mountainside. Fluffing up the soil then pushed the soil back in place.

If that is the case.. None of that 'Fill Material' is suitable to build any type of structure on unless it was compacted to a rate of 90% along with the specifications of Soils Engineer.

The engineer takes a sample of your soil back to their lab to find out when 100% compaction has been reached. They then document what steps are needed to reach that 90% compaction level.

In your case, I'm not sure I would tackle that on my own... Pay the Pro to do it right.
If it fails they are on the hook for the cost.

I have seen an 8' engineered rockery fail. It's not pretty... it pushed the house down stream off it's foundation.

..Slayer

 

look into gabion walls. If you have available rock or broken concrete these are very diy friendly. You make a row hog ring the baskets together, fill them with rock, and start the next row. These are commonly used along highways at 30+ft of hight or more. If you find someone to order them from they will normally tell you what you need for your project.

The picture was a random Google search. Check your area.
@TruckyTruck

 

Yikes... I'm not sure. I can tell you the ground where I live is super hard.

 

I definitely don't want a failed 8 foot wall!

 

Thanks, I'll check those out.

 

So what if it's not compact? Can they compact it? I'm glad you are giving it to me straight.

 

Still in progress, north side of the house.

 

got a photo of your hill?

 

Thanks dude, much appreciated!! I said the hell with it and I'm paying to have this last 50' done. My back and knees cant do it anymore.

 

Oops been drinking my medication!

The mind is willing, the body is broken. Even the wife said F it, pay to have it finished.

Damn, I definitely sympathize! I remember helping my pops at his place. 10,101ft AGL and 72 years old working circles around me.

I'll have to come check that out sometime.