Help/advice required. Flat Roof, guttering, insulation etc.

[smethwick]

Hi all.

I have a flat roof on a bedroom built above my garage approx 6m x 2.5m wide. The roof is pretty much shot and needs replacing (joists are fine). At present there is very little fall on the roof which is why it is holding a lot of water. It slopes from front to back (6m) into guttering. When replaced I'd prefer it to fall from side to side. This however would mean fitting guttering along the side which would overhang my neighbours garden. My neighbours is a corner house which is about 20ft away from my property. Is this acceptable if my neighbour agrees to it or is it a complete no go? The boundaries aren't really that well defined. The house was built in the 1930's. I phoned my local council but they said they couldn't offer any advice on the matter?

Also the original roof is a 'cold deck' construction. Due to the make up of the rest of the building and existing roof it is really only practical to replace like for like. What is the best way of insulating the new roof. Bear in mind that currently there is rockwool type insulation between the joists with no ventilation. Adding ventilation is not really an option either.

Thanks in advance.

 

[cotswoldbuilders]

When the roof is stripped of, you can add some firring strips to increase the pitch.
We normally replace the boards with insulated ply, if you cant change the extra height, replace the rockwool with Celotex or Kingspan.
Fit an EPDM rubber roof over.