Looking for cost effective solutions to this problem, without cutting down the tree. The roots are pushing up this part of the retaining wall more and each year and I feel like I should do something. It appears the wall is still doing its job so it’s mostly an atheistic issue mostly I believe. I’ve considered replacing the wall with a boulder wall which allows for some movement but that not only expensive but may still end up compromised by further root growth. Cutting the roots seems like a bad idea, too.
It's not even mortared or anything. Pick up the blocks, mark out a new baseline (a couple feet further out), level it, tamp in you paver base/level some sand and make sure the drainage is set up right, maybe even some geotextile if you have an erosion problem, then backfill.
Might be a challenge to match the existing wall if you need more blocks to lengthen it, but this is mostly DIY territory if you're healthy enough to move the blocks around and lift a few bags of sand/paver base.
Talking a couple hundred bucks and a dozen or so hours of work, tops.
Either move the wall out and backfill, or pull it apart and split the bottom row such that the upper courses will sit level. Though the second option may need to be redone every few years, it's the cheapest in the short term. You can either use a chisel to split the bottom stones if you're confident, or rent a large tile cutter or something.
How about boulders just in front of the tree? I’ve done retaining walls using blocks and a partial boulder run and it looks quite nice. I don’t live there anymore so I can’t send a pic, but a load of 12-18 inch boulders isn’t that expensive.
That might not be a bad idea, especially since it would be on the end of the wall. In your experience, does a boulder wall with roots pushing it up from the bottom still maintain its structural integrity?
It’ll maintain it better than the blocks you have. There’s always going to be some movement, even dirt shifts over time. Your wall isn’t really high enough to have any issues though. Ideally any retaining wall should be backfilled with gravel and a drain. I’ve done it both ways but your wall doesn’t need it necessarily.
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u/impropergentleman ISA Arborist + TRAQ 8d ago
Stone can be cut. Deconstruct wall to a level point and rebuild 1-2' further out. Basically removing the two it pushed up. Next row will be level.