2 years ago (in summer), had a 16 inch high retaining wall replaced. (Wall is made of those decorative concrete blocks.) At the same time, also had a new 6ft x 20ft area of concrete put down, which goes from a deck over to the top of the retaining wall. (6ft between deck and top of retaining wall.) After the first winter, part of the concrete was now higher than the retaining wall top, whereas it originally was at the same level as the top of the wall. The top of the wall in just a very short spot right next to that raised concrete seemed to be ever so slightly less level than the rest of the wall (it wasn't that way before winter). During the second winter, the concrete got a lot higher than the top of the wall. But a couple of months later, it all went down to being at the same level as the top of the wall, and has been there ever since. No cracks in the concrete, fortunately. No additional spots on the wall appear to be unlevel. Rest of wall appears fine. (Wall goes almost halfway around the property.)

Do I need to be concerned about this? What could likely be the cause and what could likely be done about it? FYI: The 6ft wide space immediately beyond the 20ft length of this new concrete (between house and top of retaining wall) will be dug up in the near future to fix a crack in the home foundation. Also, although the company that built the retaining wall and put down the concrete gave it a 5 year warranty, they are so unreliable at showing up and returning calls that claiming the warranty would be a hopeless case. (Ex: They wouldn't show up or call when they were scheduled to do the original job, wouldn't return calls for a couple of weeks, then after a couple of weeks would just show up on a random day to start the job without ever calling or scheduling. I didn't want to use this company, but someone in the house insisted cause they were referred by a family member. Now she knows never to use them again.)

 

It's not the concrete that rises, it's the ground underneath.

Ground moves with seasons, wet ground freezes, expands, thaws out settles.

Retaining walls need a compacted gravel base, this acts as a way to divert water down which lessens the impact of heaving.

A simple fix, nope, couple years from now when it is all twisted up, tear it down, put in a footer and rebuild!

 

Yes, you need to be concerned. That movement stands a good chance of eventually destroying the patio or retaining wall. As Marq1 mentioned. It's the ground underneath moving and it's pushing your concrete structure around. So, already you know the soil is winning and the concrete is loosing. It won't heal itself but it can get worse.

 

They did appear to put down a compacted gravel base. This took them longer than the actual wall in fact.

Regarding the rest of the area, mentioned in my original post above, which is next to the concrete patio and between the house and the top of the wall. This will be dug up in the near future to fix the home foundation. When that is dug up, is there anything that can be done to increase drainage to prevent this happening from the rest of the space between wall and house without rebuilding the wall? Such as underground tubes for collecting moisture and draining it out past the wall? Or anything else? (There will be some concrete put down for a sidewalk in this area, but the whole thing will not be concrete.)

 

Yes, there are measures that can be taken for drainage. Since the area will be excavated that will be the best time to install.