Subscribe or Renew Membership Subscribe Renew

Extending a cinder block retaining wall.

GeorgeP's picture

I took out a large bush that was behind the retaining wall in the photos.  The bush and root system anchored the dirt on the slope to the right of the wall.  Now that it is gone I am concerned about  the dirt moving.  The slope looks worse than it is as I had to pile up a lot of dirt when digging out the stump. I want to extend the lowest tier of the retaining wall in a curve that sort of matches the curve shown on one of the photos.  

I need some advice on building the extension.  I plan on digging down to pour the footer so it matches the existing footer and also to expose the first course of blocks in the existing wall.   I assume the best way to tie the extension to the existing wall is to remove the cap bricks and cut the last cinder block in the existing wall and remove 1/2 of it so I can stagger the joints with the extension.  Is that the way to go?   Can I cut a block that is mortared in place?  

Next, can I create a curve with cinder blocks without having huge joints on the face of the wall?

Lastly what is the best way to provide drainage?  Since this is very sandy soil underneath the (Cape Cod), do I even need to worry about drainage?



It seems to me that you have (post #215159, reply #1 of 4)

It seems to me that you have a good plan in mind. You can use 1/2 blovks to make the gaps smaller in the curve and if you leave some mortar out of the back you'll have good drainage.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

If you put a diamond wheel in (post #215159, reply #2 of 4)

If you put a diamond wheel in a grinder you can cut away part of the blocks to make a tighter fit in the curve. Do the same thing with the ladder wire so you have matching reinforcing in the joints and you will have a very strong wall. We would also use rebar hooks into the footing and grout the cells about every couple feet  but that may be overkill. It is just a few more bags of concrete tho.


Ladder Wire? (post #215159, reply #3 of 4)

I planned on using rebar I. The footing  and filling those blocks with concrete.  It is a short length of wall so probably only rebar a few of the first course blocks.  What is ladder wire and how is it used?  By cutting the blocks, do you mean cutting the outside corners on the hill side of the blocks?  Can I do that with a cold chisel?


This stuff. Some looks like a (post #215159, reply #4 of 4)

This stuff. Some looks like a ladder with the cross bars at a right angle to the running poart. You lay it in the mortar joint to reinforce it laterally.