Internal insulation on back of exterior wall

[Tom079555]

My house is very cold so I have decided to try insulating my living room wall. It's the inside being insulated as the house is in a conservation area, meaning the outside is a no go.

I have built a stud wall and placed foil back foam boards snugly into the frame. As the room is not huge, the insulation used is 50mm thick to avoid loss of internal floor space.

Question1: As the foam board is not as deep as the frame its pressed into (leaving about a 2cm gap behind each board) will this cause a mould issue?

Question 2: I'm understanding that I should place a moisture barrier on top of the insulation before applying the plasterboard. What type of barrier is best, and should I have also used one behind the frame also?

 

[^woody^]

There should be no gaps orair voids within the frame.

You should really have insulation across the face of the frame too, otherwise there is a high risk of pattern staining on the finished decorations from the cold bridge of the timber.

 

[hamd01]

There should be no gaps orair voids within the frame.

You should really have insulation across the face of the frame too, otherwise there is a high risk of pattern staining on the finished decorations from the cold bridge of the timber.

If its an old build in a conservation area, it could be that there is no cavity wall....in which case having a cavity behind the insulation/battens would be correct.... although 2cm would be a bit narrow.

Also regards thermal bridging, if the frame has been constructed via a top and bottom beam, then the frame might not even be touching the wall.

 

[Tom079555]

The frame is actually connected directly on to the wall. It was just unfortunate that the foam board does not fully fit the depth.

Should I just place wool insulation behind the board to pad it all out, and then foam spray any gaps around the to make it air tight?