Missing bricks under chimney stack

[bgrey]

Hey guys. Digging out part of my patio and noticed under the chimney there is a void which is just soil. Is this normal? Should I be concerned? Does it need digging out and backfilling or am I best just leaving it?
Any advise or other experiences of this welcome. Mantle of bricks is about a foot under patio level. Thanks in advance.

 

[stevie888]

If you dig a bit deeper I think you'll the bricks corbel out from the main foundation

 

[Wayners]

Ash dump hole maybe.
I've got this foggy memory of holes at the back of chimney to aid in cleaning it out.

Maybe that?

 

[^woody^]

If you've scraped that soil out for no reason, best stop, refill the hole with concrete and then finish what you are doing around the walls.

 

[Deluks]

You may have undermined the house! Older houses didn't always have a 'proper' foundation.

 

[tony1851]

Those bricks which are 'edge-on' are part of the foundation to the chimney, so your hole is actually a void you've dug under the foundation.
The casualness of it might surprise you, but the ground looks to be sandy and probably of reasonable bearing capacity; the builders of old would have known what they were doing. The house is still there after (120?) years.
Backfill it with weak-mix concrete rammed well-in, and in future perhaps avoid the temptation to dig holes under your walls!

 

[bgrey]

Thanks all. Lots to think about! Didn't consider that it could be foundations as there is a cellar below the house.