Insulation Under The Roof

Water is insulation s enemy.

Insulation under the roof. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing. 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. 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. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

The insulation boards are best fitted under the roof structure whilst the mineral wool can be inserted between the beams of the roof. The material is compressible and is thus easy to fit and is less likely to cause cracks. Arguably the most popular pitched roof solution installing insulation between and under the rafters uses the depth of the structural timbers to best effect. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.

An efficient room in a roof in a new build property where over rafter insulation is not desirable. 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.