Freezing cold dormer bedroom

[Jay69]

Hi
Looking for some advice about insulating a dormer bedroom in a 1960,s house. The bedroom is directly above an open porch. From what I can work out I need to insulate both the walls that cut into the roof space.

I am presuming if I insulate the sides in the roof space with kingspan top to bottom and seal sides with tape that should do the trick ?

Few issues I can't seem to figure out

1) do I need any type of vapour membrane ?
2) I need to run wires through the board to reconnect the sockets and wiring for the lights. How is this done and won't this compromise the insulation?
3) is there a fire risk because of this and do I need to rewire with another type of cable?
4) best way to insulate the floor without ripping up the boards

 

[endecotp]

What exactly is the construction of the floor, through to the porch ceiling? It may be easiest from below.

Regarding the wiring, yes wires can overheat once embedded in insulation. Lighting wires are not a problem but sockets are. I think short distances are OK but I don't recall the details.

 

[garyo]

It's it one of those bungalows where you could move the front door forward a metre to solve the floor problem, and give yourself some more inside space at the same time ?

 

[Jay69]

Floor is normal wooden floorboard above a porch which from the sound of it is plasterboard ceiling. if I did go through the plastering from below is it just a case of kingspan in there and plaster over it ?

Still not sure how to go about the socket wiring for the walls through the insulation. Would it need to come straight out and what type of wiring would I need to upgrade to ?
Does it need a membrane on the walls and porch ceiling if thats best ?

Currently getting damp air either through the walls which are very cold to touch and to some extent through floor.

Garyo could brick/window over the porch but would look a bit boxy so trying to avoid that.

 

[endecotp]

What distance from porch plasterbiard to room's floorboards?
If it's a big gap, fill with mineral wool from below.
If it's a smaller gap, using e.g. kingspan will be better but you'll need to take care to fill the gaps with expanding foam to achieve a seal.

 

[cjard]

Pics please