Does anyone have much experience of the costs of lifting a home versus excavation? Trying to make a 7' high storage space under a two story home into a 9' tall living space. 1400 foot square footprint, 28' wide lot. I'm thinking excavation is going to be more expensive, especially since we are working on lot line construction on an upslope lot (typical San Francisco condition).
If your foundation walls go down at least two feet below the already existing floor level in the storage space I'd just excavate. But if excavation leads you to change the foundation walls in anyway I'd just lift (you'd probably end up lifting to change the foundation anyway).
My Dad did this by hand when I was in middle school. It took him a couple of years, but he was able to do it himself by jacking the house little by little in several parts. He then dug it all out by hand, buckets and finally a conveyor belt. I don't think I would recommend this method as it had uneven lifting which caused the plaster to pop open.
You can excavate within the existing footings an beyond their depth but you'll need a structural engineer to detail how to keep the footings from being undermined. I've seen this done before with a concrete grade beam along the interior perimeter of the footings.
Lifting a House versus Excavation
Does anyone have much experience of the costs of lifting a home versus excavation? Trying to make a 7' high storage space under a two story home into a 9' tall living space. 1400 foot square footprint, 28' wide lot. I'm thinking excavation is going to be more expensive, especially since we are working on lot line construction on an upslope lot (typical San Francisco condition).
Bad idea. Very expensive and all you've got at the end is basement.
lifting the house adds daylighting opportunities, but higher risk and cost.
If your foundation walls go down at least two feet below the already existing floor level in the storage space I'd just excavate. But if excavation leads you to change the foundation walls in anyway I'd just lift (you'd probably end up lifting to change the foundation anyway).
My Dad did this by hand when I was in middle school. It took him a couple of years, but he was able to do it himself by jacking the house little by little in several parts. He then dug it all out by hand, buckets and finally a conveyor belt. I don't think I would recommend this method as it had uneven lifting which caused the plaster to pop open.
You can excavate within the existing footings an beyond their depth but you'll need a structural engineer to detail how to keep the footings from being undermined. I've seen this done before with a concrete grade beam along the interior perimeter of the footings.
What is the existing house constructed with? Wood frame Victorian is easier to lift than brick.
If you're gonna lift, make sure you don't exceed zoning height limits.
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