Retaining Wall Design

[PondTBD]

Hi, I posted this question in another thread but am starting a new one for more thoughts.

I'm designing a pond that is half in a hill slope and half above grade. It's small - only about 600 gallons 3 x 4ft, 2 ft deep. I not sure what to use for the retaining wall on the above ground side which will be about 8-12 inches tall. I've been looking at retaining wall bricks since I don't have a lot of area to add additional structure.

The retaining wall bricks have a lip on the bottom of the back side that pushes on the back of lower brick when dirt is filled in behind it. So, the top brick is a little behind the lower brick for a slight stair case profile.
http://www.adbrimasonry.com.au/homeowner/retaining-walls/see-all-retaining-walls/windsor-1
The brick is designed to allow up to 3 foot walls without reinforcement, but the manufacturer doesn't know if it will work with water pushing on a pond liner. Their design concept also doesn't use wet cement for the footer, just smooth out the powered cement mix and let it harden with moisture.

To be safe, i'm thinking about drilling holes thru the retaining wall bricks for rebar. The retaining wall bricks don't normally need any adhesive but the manufacturer recommended using a masonry adhesive.

Questions;
Has anyone built a retaining wall using retaining wall bricks like these?
Is masonry adhesive between the bricks sufficient or should I use mortar?
Should I use rebar? If so, how deep into the soil should it go?
Does it sound ok to use dry cement for the footer and then let it harden on its own?
Any other thoughts?

Thank you!

 

[Ruben Miranda]

Hello
The concreate retaining blocks can work.
It is better if they lean in as they get higher.
But for your 2ft height you could chip off the lip (not on the bottom row)
And use concreate adhesive and make sure you stagger them for added stregnthed. I take it you will use a liner ?
I would go up with the block to the prefered height put in liner make sure it is all the way down and stregnthed (best way is put in liner and fill with water) and then use a adhesive to hold liner down , then glue down the cap for a clean look and trim off excess liner.

Oh yea
First row of block should be burried half to 3/4 1n the ground for added strength, and th first t 2,rolls should have a a gap in between maybe every other block. This is called a weeping well just in case you get water in between the liner and the the water can exscape and not cause damage.

Ruben

 

[Jimmy Gibson]

I used retaining wall blocks with rebar and Quickrete......I also have one block buried in the ground all the way around for support. Worked out well for me

 

[PondTBD]

Hello
The concreate retaining blocks can work.
It is better if they lean in as they get higher.
But for your 2ft height you could chip off the lip (not on the bottom row)
And use concreate adhesive and make sure you stagger them for added stregnthed. I take it you will use a liner ?
I would go up with the block to the prefered height put in liner make sure it is all the way down and stregnthed (best way is put in liner and fill with water) and then use a adhesive to hold liner down , then glue down the cap for a clean look and trim off excess liner.

Oh yea
First row of block should be burried half to 3/4 1n the ground for added strength, and th first t 2,rolls should have a a gap in between maybe every other block. This is called a weeping well just in case you get water in between the liner and the the water can exscape and not cause damage.

Ruben

Hi Ruben,

I'm confused about your comment to chip off the lip. The lip is on the bottom back side of the block so it fits over the back of the lower block causing the wall to lean in a bit on each level.

Yes, I plan to stagger and use adhesive. I may want to modify the retaining wall a bit later, do you know if I can pop a couple of bricks off the top with a hammer and chisel without causing a lot of damage?

Yes, I plan to use a liner along with protective felt below that. Do you think I should run protective felt up the brick retaining wall too? Pond shop selling the liner said they don't use it on streams and didn't mention using on the retaining wall.

Good idea to glue cap down on liner for last row.

Good idea on the gap in between blocks. Another retaining wall block seller told me to put Ag pipe under the lowest part of the pond out to a lower level to keep water from building up under the liner. I'm not sure if I have enough down hill slope to do that since I planned about 1 foot deeper than the bottom of the retainer wall.

Steve

 

[PondTBD]

View attachment 97081 View attachment 97082 View attachment 97083

I used retaining wall blocks with rebar and Quickrete......I also have one block buried in the ground all the way around for support. Worked out well for me

Jimmy, Did you sink the rebar in the ground below your footing? If so, how far? -thx

 

[Jimmy Gibson]

Jimmy, Did you sink the rebar in the ground below your footing? If so, how far? -thx

Around 18".....pond is finished holding water and doing great

 

[Jimmy Gibson]

I also put a skim coat of motar/sand mix on the walls to fill in the gaps in the block.....also took the Underlayment up the sides

 

[Ruben Miranda]

Hello
Yes if you chip. Off the lip you can make them even and go straight up
And not have them lean in.

I found the adhesive to be very strong and not pop off very easy at all.
Not to say a hammer and chisel won't pop it off but good chance it will crack down the middle.

 

[Mmathis]

For safety sake I would go with rebar and adhesive.

 

[Jimmy Gibson]

For safety sake I would go with rebar and adhesive.

The only thing is.... Without concrete or Motar filling the web in the block the rebar will not hold the block and if you fill each web there is no need for adhesive

 

[Ruben Miranda]

Hi
The block ie edgers he is talking about using are not hollow.
So for rebar to be any good at all he would have to
Dig a footing at least a foot deep and 6 to 10 inches wide
Drill each block for the rebar to slide through.
These esters don't drill very good most time they split/crack.

If you want to use block and rebar and be cost effective
Use a 3 x 12 block and skin the out side with moter or stucco.

Ruben

 

[morewater]

The most important aspects of retaining wall construction are the following:

Use the proper sized block for the application, overall height and correct, successive set-back per tier.
Proper stacking, all blocks must cover the two blocks beneath.
Proper adhesive for the block type utilized.
BASE - at the very least one foot in depth. The initial excavation conpacted with a jumping-jack, 6-8" of 3/4 clear crusher-run (compacted), 2-4" A-gravel (compacted), 2-4" limestone screenings (compacted).
Each layer should be "wetted" prior to compacting and re-wetted prior to successive compactions.
Use stone that uses matched coping stone for finishing.

 

[sissy]

mine from lowes