Wall insulation on new wall as part off loft extension

[kirunsg]

Hi all,

I would really appreciate some advice on the insulation on the external wall to the loft conversion my builders are currently undertaking. Given that my property is on a hilly area, there is a gap between the 1st floor ceiling and the loft room floor. The builders have insulated the walls above the floor level but not at the level below the floor. This has resulted in a 60-70mm external wall area with just the ply and the tiles on the exterior. My builders are saying no insulation is needed on that part of the wall as the 1st floor ceiling is insulated and the loft room floor is insulated as well, hence no need for that part of the wall to be insulated. Are my builders correct?

Thanks for your guidance.

 

[freddiemercurystwin]

So is that the external wall we're looking at there? How have you ended up with a gap between the existng first floor ceiling and the new loft floor?

 

[kirunsg]

Yes the ply at the far end is the external wall i am referring to. That wall is just a ply with tiles on the outside. The 1st floor is on 2 levels given the property is on a hilly area. There is the main stairs that leads to a landing where there is one bedroom and a few more steps on the bend that leads to the other 2 bedrooms. The loft has followed the same structure where there is one room on the first platform and a second room after a few more steps on the bend.

 

[freddiemercurystwin]

Well I don't follow the layout but as it's a new external wall it should definitely be insulated. The new insulation should completely encompass the inside of the house, the new insulation effectively forms a bubble or a continuous barrier between the inside and the outside, as highlighted in this example and encircled in the orange line.

 

[kirunsg]

Thanks a lot, that's really helpful!