Poured retaining wall - Sloped vs Stagged top

[myyaz33]

Working towards prepping for a retaining wall in the backyard and have been looking at different options. I am planning for a poured wall vs block/brick. The wall will decrease in height a couple feet and I like the looks of the sloping wall vs a 90 degree stagger. I have looked all over the internet to find a good method to get the slope, but cannot find a document or video detailing a method. Can anyone point me to a good site or help enlighten me?

I am thinking a chalk line inside the form with the slope and once the concrete is high enough in the for, then screw in a 2x8 on the line on both sides of the forms. Once the concrete sets enough, remove the 2x8 and finish the top. Am I close? I could see it being done in 2 pours as well.

 

[RNeumann]

The chalk line would work. Then just drive little finish nails to the line. That will guide you along your slope. Either that or cut the forms....:

 

[myyaz33]

The chalk line would work. Then just drive little finish nails to the line. That will guide you along your slope. Either that or cut the forms....:

I should have mentioned i plan to use Symons Steel-ply forms instead of plywood, so i cant cut the forms. Thanks for your input.

 

[Streetcar]

Install piece of trim cut on 45 degree angle at proposed height. Chamfered edge will look better than straight edge

 

[myyaz33]

I like the idea of the chamfered edge and saw that in youtube (Essential Craftsman) video. I guess the original issue of how to get the slope, still exists.

 

[DJ54]

Use the chamfer strip as guide for the top of the slope. If your concrete is stiff enough, it should be no problem conforming to the slope,and staying in place. You may need to finish a couple times, but it will work. This is how we did small bridge, and/or box culvert wing walls, and they varied from a 30º, to 45º slope. If a bit has come over the top of the chamfer strip when you pull it off, finish it off with a masonry finish stone. A concrete vibrator will be a big help too, depending on the height of the wall. Just don't over do it. I got one from Harbor Freight for small jobs here at home, and worked great. You just need to tap it lightly on something solid, to start it vibrating.

 

[myyaz33]

appreciate the input and I do have one of those HF vibrator (blue) that I plan to use. The wall is 32ft length and goes from 8ft high down to 6ft with the slope starting around halfway. I figure if I pump it in, the slump will be less and thus the concrete would want to run over the 6ft portion when we fill the 8ft end. I guess if the concrete stays more in place than I am imagining then we should be fine. Any chance you have a picture or two of your bridge/ box culvert?

 

[4570Man]

Concrete won’t flow down a 2 foot drop over 16 feet. Just start at the low end.

 

[sodamo]

Someone should be able to tell you what slump to order.
I think this was a bit steeper

 

[EddieWalker]

appreciate the input and I do have one of those HF vibrator (blue) that I plan to use. The wall is 32ft length and goes from 8ft high down to 6ft with the slope starting around halfway. I figure if I pump it in, the slump will be less and thus the concrete would want to run over the 6ft portion when we fill the 8ft end. I guess if the concrete stays more in place than I am imagining then we should be fine. Any chance you have a picture or two of your bridge/ box culvert?

I've done a fair amount of concrete work, but I'm not an expert or even close. Retaining walls fail on a regular bases because of the amount of pressure put on them by the soil when it gets saturated with water and even more so when the soil freezes.

An 8 foot wall is way above where I'm comfortable designing or engineering. How deep will your footings be? Will you have posts along the wall? What size rebar will you be using and at what spacing? Will you incorporate a deadman? What thickness will your wall be? How will you brace your forms to deal with blowout?

Instead of pouring a concrete retaining wall that tall, I would go with retaining wall blocks engineered for an 8 foot wall and allow for drainage behind the wall. Then I would cap it with concrete to give it that smooth finish on the top that you are wanting. This is very common.