huangyhg

replacement of existing foundation
looking for any input on following.
customer is looking to have existing block foundation of small ranch home removed & replaced with concrete foundation walls.
existing walls are failing in various ways, such as horizontal cracking, vertical corner cracks,water penetration.
any input in the procedure process of removing existing walls or any prior experience in such a matter will be greatly appriciated...
this is an underpinning effort that would normally require temporary shoring of the house in either small sections at a time or the entire footprint of the house all at once.
with the temp. shoring in place, the perimeter walls may be excavated, removed, and replaced. you might want to look at the condition of the footings as well and replace those if necessary.
this requires significant excavation (if its a basement) and less amounts if a crawlspace but the concept is the same either way.
with a basement, its a good idea to provide an improved foundation/wall drainage system and waterproofing on the walls.
once the walls are complete, the shoring can be removed to re-establish the support on the new walls. there might be slight changes in levelness and some movement in all this so the owner should be warned that wall cracks might occur. photographing the interior walls prior to the work is a good idea in that it positively documents the original condition.
this is reasonable striaghtforward proceedure and jae sums it up nicely. one thing to be aware of when temporarily holding up any stucture is the potential of earthquake movements. make sure everything is properly supported and that a slight earthquake movement will not shake the building of the temporary supports.
intrusion prepakt
if there is not excessive movement present and the footer is entact, then consider reinforcement of the existing block wall (probably hollow cmu without reinforcement or grout) and providing the "waterproofing" as jae suggests. the basement wall cracks are probably from soil surcharge not building loading.
if they exist in your area, contact a house mover. move the house out of the way and construct the basement without any obstructions. your lot size may not allow the house to be moved out of the way, however.

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