Knee Wall Insulation

[MidsNewBuild19]

Property is 4.5 years old.
Cold has been an issue since we moved in and a few years back we and the developer found that the insulation behind the knee walls of the 2nd floor were not to drawing. Instead of insulating the ceiling and knee wall, the rigid insulation in the rafters runs down to the eaves.
My complaint was that this area is now part of the house space and therefore require more heat power and increase the energy needed to heat the adjacent rooms.
Developer agrees and is shortly ADDING the insulation to the ceiling/knee wall.
As you can see the original insulation is not a fantastic installation…

I don’t expect this to cause any issues. I hope that it will help keep more warm air in the rooms which border this space. Anyone had a similar experience or any words of warning?

[MidsNewBuild19]

Another image added

[New Home Expert]

The ceiling must be insulated - with 250mm fibreglass. Otherwise you are heating a roof space.
I agree the small wall under a dormer window is it? should also be insulated.

Of concern is why building control and warranty providers  didn't flag this up during their final inspection?

[MidsNewBuild19]

Thanks for the reply.
In their eyes it ‘was’ insulated at rafter level… but evidence has shown that this cavity is cold because the rafter insulation is inadequate. There was also no sealing preventing drafts/cold air from entering the floor/ceiling voids across the entire length of the house.
We had a thermal survey done and it was easy to see from the rooms in the attic and the ceilings below.
They’ve almost completed the work so we shall see if there is a noticeable improvement.

[MidsNewBuild19]

I do still think there is some insulation missing in the ceiling above the dormers but I’ll have to venture into the loft space myself to have a look at that.

[MidsNewBuild19]

So the additional 9 rolls of insulation that were fitted has made a big difference to the rooms below, but the 3rd floor less so. I did more digging this evening and the small ceiling on the dormers as no insulation. This is the ceiling directly above the radiators.

I think I’ll just do this once myself and pop a few layers in there… crazy to think someone laid insulation in the rest of the attic and didn’t do this area 

[MidsNewBuild19]

Got in the loft today and got a bit closer with the hope of getting some insulation in there. Sadly the void is too far out of reach for me to do a good job.
Probably best I pass this back to the developer again.

Do you think it will be sufficient to feed in wool insulation or would it be preferable to take the ceiling down and do it that way? Using a mix or wool and rigid foam insulation?

[New Home Expert]

You should also have a air tightness test to to find out if there are holes where your expensive warm air is being cooled by draughts.

As for the dormers, it should be possible to put use blown in fibres and top with a fibreglass quilt to stop it moving about. Or fibreglass pushed in with a stick. It wont be perfect but taking down your ceiling is drastic.  Don't lt them use the foam stuff.