Old house, new paving issues - Making sense of different ground heights

[efunc]

Hello all,

I hope this is the right section for this. As a rank amateur this is a bit perplexing, but it'll probably be bleedin' obvious to you guys! I was planing to finish paving a small plot at the back of my parents house that was left abandoned by workmen, but I got concerned about the air brick here so decided to hold off before proceeding. This area has a concrete base which was previously tarmac'ed, but that's been stripped off and block paving is now laid on some sharp sand. A picture speaks a thousand words so here's a few snaps:







This picture shows how the height of the new block paving will be level with the height of the existing concrete platform at the side (and front) of the house that was already there when my parents bought it over 35 years ago. This is also level with the base of that vent. Furthermore, due to minor subsidence the insurers added that concrete reinforcement to the side which is even higher:



This concrete underpinning is just at the level of the original door step at the side of the house here:



Coming round to to rear of the house, I only just noticed that the contractor had blocked off half the air brick here when they paved it 3 years ago, even though the height of this paving is more or less in line with the concrete at the side of the house. This area has an existing concrete base which I presume is original because it was there when they bought the house in the 70's. About 25 years ago they had the area stretching round to the other side of the house laid over with crazy paving, so it was about the same height as the new block paving is:




So, what I'm unclear about is what the height of the DPC is and whether or not it's safe to pave this new section up to the base of that air brick, or whether I should leave a 1 ft gap and fill it with gravel or just leave the concrete base? Surely it doesn't have to be excavated down or anything? This is a detached house of relatively flat ground and clearly some of the existing concrete around the house is at the same height, or higher, than the paving I'm about to complete. In 30 years or so I've not known there to have been any damp or drainage problems with the property, so should I be concerned? Are these inconsistencies in paving height normal?

Thanks for reading!

[lutonlagerlout]

that airbrick although not quite right is border line ok,if your worried make a little recess as you mentioned
the DPC is generally level with the bottom of your door frames/internal floors
but this is not always the case
luckily for you you have roughcast render which is a great waterproof finish
if you dont have any damp issues now i would leave alone

BTW that doesnt look like underpinning from here??
when we have done it you wouldn't leave a fillet round the outside,it makes no sense
LLL

[efunc]

Thanks for the reply, that's brilliant. I may just pave right up to the wall then as it'll look much neater and the height will be flush with the adjoining old concrete path at the side of the house. I guess I was also concerned about the property valuation resulting from doing this though if it was frowned upon by a surveyor perhaps.

regarding the underpinning, that was done a good while ago, but I distinctly remember the insurers sending around a bunch of engineers tasked with propping up the subsidence, and that's what they designed. I'm not sure what it's called, but the subsidence seems to have been corrected.

[seanandruby]

The fillet does look independent of the lower base and a slight gap between that and the wall. Have you tapped it with an hammer to see if it is solid, or tried to prise it away from the wall?