Backyard Fencing and Dry Laid Wall

by Jennifer
(Ohio)

Hello. We just built a home on top of a hill. In order to get a backyard for our boys to play, we had to put in a retaining wall which is 10-12 feet at it's highest point. The wall is made of concrete blocks that are dry mounted. The builder had a fencing company place an aluminum fence in the top layer of the wall. We moved in in November and during a December storm we noticed the fence along with the blocks the posts were in blew over the back of the wall. The posts were only drilled into the cap blocks and no glue or cement was used to anchor any of the blocks on the wall. Since that time, the wall guy has "glued" the blocks with the posts in them twice now, and the blocks are still completely loose. You can gently push them over and completely out of the rest of the wall. I'm being told so many different things by our contractor, our fence people and our wall guy. Now they want to reglue it again! Is it safe to put a fence in the wall? If so, can you really just put the fence posts in the cap layer and glue it? Should I be pushing to have the fence installed in the ground? Problem is the back yard is so small and putting the fence in the ground will take away 2-3 feet of space! We would like to have it in the wall (ONLY IF IT'S SAFE) -but what is the proper way or should we bite the bullet and install it in the ground? I have 3 young boys.

HELP!!!!

ANSWER

Hi Jennifer,
A 10 foot high wall?! YIKES! This wall should have been engineered. I am surprised if it wasn't. If it was, then where was the inspector to look it over to make sure it was installed correctly? Assuming the wall was all done right and the issue is just with the fencing...well that is a better situation, somewhat.

I am not sure how fences are installed on dry laid walls, but your certainly sound like an issue. If you were to install it in the ground, they would have to dig down and install it in concrete which would be so much more secure.

By the way, if the area behind the wall is fill, I believe that is another problem. Typically if an area is fill, the soil is tamped in lifts to compact it for situations where concrete footings or similar must be used. Sometime stone is used in place of compacted fill. However doing that in the back of a 10 - 12' high dry laid retaining wall is questionable.

I would highly recommend you consult a structural engineer. This is their specialty.