Loft boards insulation in roof trusses

[theDIYkid]

You can build a stud frame onto the rafters if you need more. But it's not the sound going up. It's the sound between walls you should worry about

I could but that would make the room to small, especially height wise.

 

[theDIYkid]

What is the setup at the ridge tiles. Is it a cement or dry ridge or...

Have you considered a flat roof instead of them joining .. also... After insulation... There will be a gap at the top... As you'll lose about 8-15cm either side.... So plaster board will intersect lower that your. Ridge beam...

I dont understand, the ridge beam which joins both side rafters is wht I mean by leaving a small gap at the top of each insulation so that air can go over the top and to the other side, concrete tiles outside and above the ridge.

 

[theDIYkid]

You need a 50mm continuous air gap over the top of the insulation where it follows the pitch of the roof ,with ventilation at eaves and ridge.
Incidentally,your underfelt looks to be the 'old ' type that isn't breathable.

Ok so defo no less than 50mm even if I use Rockwool. At the ridge you mean leave a gap for air to pass thru to the other side rafters yea?

 

[Leofric]

At the ridge you mean leave a gap for air to pass thru to the other side rafters yea?

With a warm roof where insulation follows the pitch of the roof the idea is to ventilate the gap between the insulation and the roofing membrane. If you Google roof ventilation you should be able to find plenty of examples showing the principles of ventilating pitched roofs like eaves ventilation at least equivalent to a 25mm continuous gap and ridge ventilation situations.