Terrace retaining wall

frumdogg

Hi, I am new to this forum and to the home ownership world, so please bear with me.

Our backyard has a hill in it which has a terrace with a variety of plants that thrive throughout the growing season. When we moved in the retaining wall in the terrace was settling and I spent an afternoon resetting the upper two tiers by leveling out the soil and using some sand. Now, a year later, it has started to settle again. Of course, the amount of rain we have had the last year has been above normal, and there is a spring above the wall (which I plan to divert this summer as well).

Has anyone had any experience with this type of an issue and could offer some insight into how they repaired the retaining wall once and for all? I have attached a picture to show where the settlement has occured in the upper two tiers.

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Daniel Holzman

That looks like a segmental block retaining wall with a lot more settlement than is considered normal for such a wall. Also, that wall is so tall that it almost certainly should have been installed using earth reinforcing mesh, steel straps or similar. Not sure you know, but in a segmental block retaining wall the blocks themselves provide only a small portion of the wall support, mostly the soil holds up the wall, which is why you need to reinforce the soil when the wall gets tall.

But I don't see evidence that the wall is tilting in your photo, so perhaps the major issue is that the base for the block was not adequately prepared. Maybe the block is not sitting on adequately compacted soil, or possibly the soil underneath is weak and compressible. In any case, you most likely need to remove all the block, and prepare the foundation correctly for the block, following manufacturer recommendations for a wall of your height and terracing.

Most DIY block walls are relatively short, and the foundation is not too important. Your wall is much taller than the average DIY project, hence should have been designed much more carefully, and constructed strictly according to manufacturer recommendations and good design practice, which means proper drainage, proper foundation, and proper earth reinforcing. Maybe you can get the original plans for the wall, or contact the original contractor, to see exactly what they did. Maybe they pulled a building permit and you can review that. My guess is the foundation was not compacted correctly, and maybe the builder failed to dig down to strong, naturally occurring soil. The plans will tell.

frumdogg

Thanks for the info, I know from talking to the neighbors that a permit was not pulled, that it was simply a "weekend project". The picture doesn't do much justice, I should have taken it yesterday before the snow started. The tilt in the middle that is showing in the center row of blocks is indicative of part of the problem. If the wind settles down today I will venture out to snap a few more shots.

Phillies48

It all depends on how this wall was originally installed. I faced almost the exact same problem a few years ago. We ended up removing the wall however, not because we couldn't figure it out, but because we re did our entire backyard. My retaining wall was a little different than this so I am not completely sure as to how you will fix this. I found the answer to mine by having a landscaper come check it out and offer suggestions. Doing it yourself is very possibly but the help of a professional will greatly help.