A question for you engineers out there...

[iluvzbeach]

DH and I are looking at a property in southern Oregon that is new construction. It is built in to the side of a hill/mountain and the builder has put in a very stout looking retaining wall, this is not something we have any experience with previously. Based on research I've done online it appears to be a cantilever retaining wall, very thick base in the ground probably four feet wide and then a poured concrete wall (6-8" thick) that is approximately 8-10' tall. The wall has rebar in it as well.

Our question is around the backfill. The builder has indicated that you don't put backfill behind this type of retaining wall, but this goes against everything DH has ever understood about retaining walls.  It should be noted that the cut out area is a very hard packed soil/rock and not any type of filler that was brought in from the outside.

Obviously we will hire an engineer to inspect and provide his/her opinion before we close on any such deal, but I would be interested in any information you can share based upon your expertise in the area. I understand that any response you provide is informational only and that we need to continue to proceed with a paid inspection and recommendation about how to proceed.

What are your thoughts?  Thank you in advance for taking the time to read and respond.

[Glenstache]

Ask for a copy of the stamped plans for the retaining wall. See if the construction conforms to the plans. If there aren't any, then it is not an engineered structure (and may have permit issues depending on local codes).  You may also ask to see if there is a geotechnical report associated with the property, which may not have been done for residential construction (often not). The question is if the wall was installed for based on a geotechnical assessment, or just because the builder thought it might be nice based on a hunch/professional experience. If there is an actual hazard, then the design of the wall should match the purpose. If no hazard, then the design of the wall doesn't matter as much. I'm not an engineer, but am a geologist so I look at these things from the slope stability point of view.

[iluvzbeach]

Thank you so much for taking the time to respond. This is very helpful.