On Mon, 22 May 2017 17:44:16 +0100, Tim Watts
wrote:

snip

I'm building on a slope - the PD tech notes say measure from the highest
local ground to the highest point on the building.

So worst case for you then. ;-(

No - best case. You only measure from the *highest* ground point. Any
part of the building that is lower is "for free".

Right, so your ground drops 2m over the allowed range of PD so you can
build something 2.5 + 2m high as long as you build it at the deep end?
;-) shrug


Which is reasonable as digging into the ground does not make things
worse for the neighbours.

Ask someone who needed to get their house underpinned!

I can see how you could dig out the ground on the uphill side as long
as the building was no higher than 2.5m above the ground at the
highest point. You couldn't have say the back at 2.5m and build the
front up on a raised platform.

If you dug out 2.5m at the top of the slope you could have something
5m tall or if we do it at the deep end (if I understand you correctly)
it could be 7m tall. ;-)

Cheers, T i m