Conditions for building a warm flat felt porch roof Information, help and tips on many areas of roofing including trusses, tiling, venting, insulation etc....

[GWFBall]

Hi,
I have bought a house which has a poorly built porch using the existing concrete roof/shelter and side wall from the previous open porch/entrance.
It is the old protruding counter balanced concrete slab and side wall designed only for protection from the elements whilst stood at the doorstep. A closed porch has been built around it making use of both the side wall and existing concrete roof with the rest of the porch built using PVC windows and frames.
No drainage has been installed and as a direct result there was a massive penetrating damp problem.
I have repaired the damage caused by the damp and I now need to tackle the roof and drainage issue.
My question is, would building a 'warm flat felt porch roof' atop of this original structure work?
I realise there will be extra height to consider, but is that the only problem when approaching the job or do I need to remove the original concrete roof completely?
Thank you for your time
G'

[welsh brickie]

you could have a fiberglass covering over the top of the concrete roof with insulation, a felt warm roof needs venting to prevent moisture rotting the boards, a fiberglass roof does not

[GWFBall]

Thanks mate, does the same apply to what is called a cold flat roof?
Fibreglass sounds the cheapest option, however it's the drainage that is the main issue along with cosmetics. I'm looking for a finish that is reasonably pleasing on the eye that can also accommodate drainage/guttering with ease. Fixing guttering straight to the concrete roof will not be as efficient because of the way the porch has been constructed around it.
Many thanks.
G'

[welsh brickie]

you can screw ply to the edges and then fit pvc facia on top,the gutter can then screw to the facia

[GWFBall]

What a simple idea!
Why didn't think of that first before I started looking at building a roof?
The ply and the fascia would bring the outer edge of the roof forward enough to accommodate the guttering.
Thank you!
G'