[evilgenius]

Has anyone use that Xtratherm insulation board (8x4) to insulate in between the rafters in their attic?

[GasDad]

Originally Posted by evilgenius

Has anyone use that Xtratherm insulation board (8x4) to insulate in between the rafters in their attic?

No but we have celotext (sp?) - a foil backed insulation board.

Just remember that the timbers need to have air flowing over them, so you need at least a two inch gap between the insulation and the felt under the tiles / slates.

If you have had air permeable felt installed this gap can be reduced.

[drac]

Extratherm is pretty much the same stuff as Celotex or Kingspan - a polyisocyanurate foam board. Pain in the backside to cut - be prepared to make plenty of dust! As said previously, if you have felt on the roof, you need to provide a cross flow of ventilation at least 50mm from felt to the insulation.