Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.
Insulation under the roof.
The materials used to insulate under the roof include batts of mineral or glass wool insulation held in place by battens of wood attached to and across the rafters alternatively polystyrene.
It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.
A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.
Its versatility is the key to its popularity whether being used to achieve.
Arguably the most popular pitched roof solution installing insulation between and under the rafters uses the depth of the structural timbers to best effect.
An efficient room in a roof in a new build property where over rafter insulation is not desirable.
Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be.
The quest for greater energy efficiency in buildings has led to increasing interest and need for insulation improvements in hvac equipment more airtight construction new materials and assemblies.
Senior engineer manager at icynene john broniek makes the case for the unvented attic assembly and why insulating the underside of the roof makes sense.
The material is compressible and is thus easy to fit and is less likely to cause cracks.