Nathan

- I can confirm i've measured to the nearest point on the pot - There will be no roof windows Was hoping to have a lower chimney, so wanted to confirm the calculation. Not much i can do if thats what the regulations say. Thanks for your help.

Apologies, yes it's a class 1 flue (multifuel burner)

Just wanted peoples comments on the following.We are currently having an extension built and i've realised our plans do not show the height of the chimney. From my understanding from part J is that i have to be 2300mm (horizontally) from the surface and at least a 1000mm vertically. I've done a rough drawing below (not to scale), but just wanted to check i have the right idea.