In my hunt to clear up sources of moisture in my house I had a drainage contractor in...they were installing an inspection chamber, and ensuring any of the other pipework was in good order. The joint from the old clay to the 'replaced' pipework was certainly interesting...so the work was definitely needed.
In this process they installed a drainage gulley where the rainwater downpipe went into the ground.
The old rainwater downpipe ran directly into a sealed elbow and only dropped the depth of an elbow next to the house wall. They put in a trapped gulley (at my request admittedly), they had to excavate to a further depth to make this fit in place of the original elbow, due to where the outlet comes off the gulley.
I'm concerned my foundations could have been 'offset' foundations, where the wall is built up to the edge of the foundation. As such they could have accidentally undermined the foundations by excavating this extra 20cm to make it fit. They only did this in a very narrow cut out and back filled with pea shingle after and concrete on top.
Knowing the foundation depth is tricky, as it's a solid concrete floor internally and the foundation steps to different heights around the property due to being on a hill. In the 'worst case scenario' in my head they could have probably undermined directly next to the foundation by 20cm.
If this is the case, how bad is it short term and how bad is it long term?
I've seen on the internet that building contractors sometimes tunnel narrow trenches under existing footings to add external rodding points to under house drainage for example. So the footing effectively acts as a tiny lintel. So I can't imagine it's terrible short term, but how bad is it long term...and should I be going out and digging up the concrete again where the gulley is and backfilling the thing with compacted hardcore.
(I guess I could attempt to determine the foundation depth by taking a brick out on the outside and shoving my hand in the cavity?)
In this process they installed a drainage gulley where the rainwater downpipe went into the ground.
The old rainwater downpipe ran directly into a sealed elbow and only dropped the depth of an elbow next to the house wall. They put in a trapped gulley (at my request admittedly), they had to excavate to a further depth to make this fit in place of the original elbow, due to where the outlet comes off the gulley.
I'm concerned my foundations could have been 'offset' foundations, where the wall is built up to the edge of the foundation. As such they could have accidentally undermined the foundations by excavating this extra 20cm to make it fit. They only did this in a very narrow cut out and back filled with pea shingle after and concrete on top.
Knowing the foundation depth is tricky, as it's a solid concrete floor internally and the foundation steps to different heights around the property due to being on a hill. In the 'worst case scenario' in my head they could have probably undermined directly next to the foundation by 20cm.
If this is the case, how bad is it short term and how bad is it long term?
I've seen on the internet that building contractors sometimes tunnel narrow trenches under existing footings to add external rodding points to under house drainage for example. So the footing effectively acts as a tiny lintel. So I can't imagine it's terrible short term, but how bad is it long term...and should I be going out and digging up the concrete again where the gulley is and backfilling the thing with compacted hardcore.
(I guess I could attempt to determine the foundation depth by taking a brick out on the outside and shoving my hand in the cavity?)
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