Recommended insulation types for pitched roof

[ennisjim]

Hi,

I am interesting in getting recommendations for types of insulation for my attic space which is large and could form a play area or similar. Areas to be insulated are

A. small vertical (<4ft) stud walls (4") under purlins
B. sloped roof with 6" rafters
C. attic ceiling with 6" joists.

I was thinking of using 4" rigid (or semi) isulation with slits (which apparently make fitting easier and closer fit to rafters) for A and B and 10-12" glass wool for C. Also I was planning to use insulated plasterboard (1" insulation) throughout (walls, slopes and ceiling) to add to the 4" of rigid insulation and cover the potential cold bridging of the rafters.

I know there are lots of alternatives out there, some of them very expensive, and would be interested in suggestions. I would like to buy soon and avoid the next round of material price rises.

Thanks

 

[davidoco]

The rafterloc is good stuff (not as easy to fit as the sales pitch suggests but no waste). 100mm rafterloc costs at least 15 per sq m. Rockwool 150mm costs less than 5 per sq m. Rockwool flexi 100mm about 10 per sq m.

The insulated boards are hard to handle as an 8 x 4 sheet. After fitting the rafterloc as you describe and wool in side walls, batten out and fit 25mm xtratherm/quinn/kingspan board, then your plasterboard. After fitting your choice of insulation in the vertical wall, run a 300 mm stip along the bottom edge behind the wall snug to wall and ceiling. Rockwool describe this better on their site.

Another nice product is Rockwool flexi which will fit well between the rafters on the slope [broken link removed]