27-04-21, 05:45 PM
(27-04-21, 01:26 PM)BBROWN1664 link Wrote: Looking at that photo, I would be wondering why the neighbours patio has subsided so much.
I'm pretty certain that it's because whoever built that didn't use a proper, compacted hardcore layer.
According to a http://www.landis.org.uk/soilscapes/index.cfm, this part of Portsmouth is on "Freely draining slightly acid loamy soils"
Quote:I would still be wary of undermining those walls with water running off the patio too.
The thing is, because the ground is effectively flat (the gardens to the left and right are at the same level and there's no real slope towards or away from the shed) I can't see where any soil could be washed away from/ to.
So the water should just percolate down through the soil on each side, I'm just wondering how quickly it would do this and whether it would end up waterlogging anything that was planted there.