Concrete Posts Query.

[Deleted User]

Can the posts and gravel boards drop - does/can the ground move and they drop down with it  - or what is it ??
I'm sure i'm not imagining it, i'm sure they're lower than they used to be, i gauge this by what i can now see over the fence compared to what i used to be able to.

Woolsery

Assuming this isn't the phenomenon I noticed as a child, where toilets shrank as I grew older, it would be unusual for a concrete fence or any other structure to subside uniformly. Is there any wonkiness? If there's an underground reason which affects some places more than others, you'd end up with wonky posts and boards out of level in places.

I've seen ground subside in quite a narrow area. Back in 2013 my friend used a digger to make a large 7' hole to bury some dead tree stumps for me. I thought no more about it and planted a silver birch tree there. A couple of years passed before I noticed the birch was growing much faster than ones I'd put in elsewhere, but I still didn't give it any real thought until I noticed the ground was dropping all around that tree. What I'd done was create an area of hugelkultur; the rotting stumps were supercharging the tree's growth, and as they broke down the ground was filling the voids. Today, the birch is taller than all the other trees despite sitting in a depression almost 2' deep.

A similar effect happens with underground springs. About 10 years ago, I noticed a new spring entering our small stream. Now, a small depression is forming in the land above the spring, so I assume some earth is being washed out from underground during very wet spells. The depression isn't more than 6' wide, so if there was a fence running there, some of  it would have moved, but the subsidence wouldn't have been uniform.

Eldi_Dos

New shoes ?

Failing that is fence near railway line or busy road causing posts to shuggle into ground.

In areas of high vibration you get precast concrete footing plates that go in bottom of posthole to stop this happening.

twopenny

The posts don't get lower, the ground ges higher.
Dre and wet weather can change this, soil moved by worms and other critters, just expanding due to natural composting in the soil.

It's not the posts and gravel boards sinking. Soil around the base should be tidied regularly.

[Deleted User]

Hmmm, thank you @Woolsery , @Eldi_Dos , and @twopenny.

The area is unchanged in relation to all points mentioned, no vibration etc either.

@twopenny that's a very interesting point you make regarding the ground getting higher - i had considered the ground getting higher but dismissed it - it just didn't seem right but i was obviously on the right track though, seems odd, not encountered this before.

Eldi_Dos

Have any large trees been cut down in recent years ?

[Deleted User]

No, the area is as it has been for about 12 years, nothing has happened any differently !
I suppose my train of thought was that ground sank over the course of that number of years .... i'm on the wrong track completely it seems !!!

Apodemus

Yes, it's why archaeologists have to dig! 

I have a path that I really should get around to raising as the slabs are now well below the surrounding ground level.  And a border at the front that I take soil out of every few years to stop the ground level becoming much higher than the retaining wall.  

[Deleted User]

I've been looking, again, at this - 

When i stand/sit in the back rooms of my house i can see way over the fence/post height now, whereas at the start of the year i couldn't.
I can now see 3 gardens down (in each direction) and 1 behind, whereas prior to this i couldn't see beyond my own fence height - i'm seeing into my immediate neighbours rooms !

If the ground is rising it rises ground levels overall - including the height of the houses too then.

[Deleted User]

Update on this -

It's definitely a thing !

I've spoken to several people about this and the ground indeed has dropped.

The extreme weather we've had this year - winds and heat - have meant the trees/shrubs have had to suck far more moisture out of the ground than before, thus reducing the water content so the soil/ground drops as less volume in it.

Some i've spoken to have had their fences drop considerably.
I was interested to read that professional gardeners are also commenting on this topic in relation to the changes in landscapes, small and large.

twopenny

There are a huge number of old stone walls falling or about to.

They've been fine but roots searching for moisture, drying and dying then the rain swelling the soil things are going pear shaped.

I've just dug my veg beds on a slope and there seems to be to much soil. I'm going to have to shovel  out some soil or winter rain will wash it down the slope.

No idea what's going on as the worms were defunct in the heat and not so many now.