Attic conversion insulation

attic

Not sure best place to put this. I am getting attic converted. I did a bit of research into insulation and I am putting what I am getting here. Idea is someone might find this useful and I'd also encourage some opinions if you have any. Thanks

Roof:

I have 220mm depth rafters. I am going for:
1. 150 mm Kingspan TP 10
+
2. TW 56 37.5 mm (25 mm insulation, 12.5 mm plasterboard).
Roof U-value = 0.16 per square metre.

Walls:

1. Kooltherm K18 102.5mm thickess.
Wall U value = 0.20.

Windows
2 * P10 GPL 3060 Velux.
(U value=1.3)

So what you think?

A bit pricer especially the K18 for the walls but I reckon it's better to get best insulation possible.

sydthebeat

when you say walls i assume you mean the low stud walls....
a better spec there would be to continue the thermal liner (36.5mm) down.
And then perhaps change back to a 75mm board between studs.

teh success of these insulations is all down to installation care.

They are useless of there are gaps between the insulation and the timbers they are installed within. They have to be either extermely well 'friction' fitted, or install the 'squashable' accordion type.

attic

sydthebeat wrote: »

when you say walls i assume you mean the low stud walls....
a better spec there would be to continue the thermal liner (36.5mm) down.
And then perhaps change back to a 75mm board between studs.

teh success of these insulations is all down to installation care.

They are useless of there are gaps between the insulation and the timbers they are installed within. They have to be either extermely well 'friction' fitted, or install the 'squashable' accordion type.

No studs insulation. The walls are the boundry walls of a semi detached house.

BryanF

OP dont forget about air-tightness membrane and ventilation strategy