18" x 48" blocks are fairly large blocks. However, yes landscape fabric should have been used. Back fill is a must. The base course block should be buried at least 3/4 of the way for that height wall. Did he just set the blocks at ground level and is there a gravel base? For that height wall a drain pipe should have been used behind the ground level block to get water from sitting anywhere behind it and away from the house.

He just set the blocks down at ground level with no base. I am attaching a picture of when it was in progress so you can see the type of block used. A third tier of blocks was set on top of that. I have never heard of anyone not back filling a retaining wall but unfortunately, we are working with a particularly unscrupulous person with no incentive to do a quality job. The second picture was taken from above (sorry for the poor quality, it was taken through a screen upstairs). As you can see the soil is starting to cave in behind the wall. The real question now is how difficult this will be to fix. We will likely have to hire someone to redo the work, and I am wondering if they can just dig behind the wall and put in the back fill and barrier, or if they would have to move every stone. I could see the latter being a very expensive project.

Have you paid yet? Are you ready to take action that may involve an attorney? That wall is substandard and a disaster waiting to happen.

That wall can't be repaired without taking it apart, getting a stamped drawing from an engineer, and rebuilding it properly. Those bigger wall block systems were designed to not need geogrid, which saves on excavation, but you still need a proper footer and drainage chimney. Best of luck.

kentc, we paid only in the sense that we already bought the house and some of the purchase money was set aside in escrow to ensure that the builder completed the landscaping that hadn't been done when we closed because it was February. The amount isn't that huge because we weren't really expecting to have it be a disaster like this where we would have to remove and redo a wall with blocks that size, so we will likely need to engage our attorney. Does anyone have any predictions on how much fixing something like this would cost? Any ballpark estimates are welcome, maybe we can make a game of our situation and the closest guess can get a prize. :)

P.S. Maybe the prize can be this pile of landscaping debris that they left piled to the side of our yard.

yeah gonna pass on that game. The actual cost is going to be somewhere between what your lawyer's expert witness comes up with and what the builder's expert comes up with.

Sounds about right. If anyone can learn a lesson from this, it's never buy new construction.

Erin, I'm not sure if you can message directly but I would like to know about your builder and how that actually ended up. and your lesson is wrong, we bought a renovated old home from the same builder and are in a similar situation. I was wondering if you can help me out with information.

Just followed you but can't pm. You should be able to message me directly now.