Raising ceiling height of flat roof extension

[Porthole]

Hello - we are starting out on a new extension and currently at the planning stage. We would like to go for permitted development due to speed but the maximum eves height is 3 metres. It seems that this would result in a ceiling height in the extension which is lower that than of the existing house (existing house ceiling height = 2570mm). We are trying to keep ceiling height high (due to tall family members!) and consistent with the existing house. Also, as the extension is quite deep (6 metres), our preference is for a higher ceiling in the extension to avoid a "tunnel effect" when looking out to the garden.

 

Please can I ask if anyone has any suggestions on reducing the thickness of the flat roof of the extension? I suspect it would be down to high performing thinner insulation but wondered if anyone has practical experience in this matter. Our house is cold and so we don't really want to compromise on the insulating properties. Any comments gratefully received as we are very new to this. Thank you!!

[DevilDamo]

Is there scope to accommodate a pitched roof as a 3m eaves height and 4m overall height is usually a lot more achievable?

[Porthole]

Maybe but we do like the modern look of a flat roof extension. I think 4m might be quite close to the window sills on the first floor - would need to check. Thanks for the suggestion.

[Porthole]

By the way, on a different note, we are in Elmbridge so if anyone has had experience of getting a higher eves height on a flat roof via planning permission, then would be grateful if you could share your experiences. 

[Big Jimbo]

You could do as my drawing. Parapet wall either side. Nice hight flat roof, and drop to required height for eaves. You will have to twist my image, cause I am crap on phones and computers

[JohnB]

The best way for the insulation part would be to get spray foam insulation. You can then decide the thickness you require yourself.