The 2015 irc requires r 49 insulation for ceilings with attic spaces.
Continuous insulation on attic eave wall.
Gables to be insulated as exterior walls.
Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no.
Continuous insulation products can also serve as the water resistant barrier and air barrier for a structure providing a 3 in 1 building envelope solution.
Insulation cover should be even and continuous right to the eaves.
Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1.
Design the roof to allow full insulation over the top plates of the exterior walls.
So i ll start by saying something that might sound controversial but really isn t.
R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves.
Climate zones 1 5 and 8 16 wall assemblies must not exceed a maximum u factor of 0 051 climate zones 6 7 wall assemblies must not exceed a maximum u factor of 0 065 mineral wool performance attic.
Attic insulation unvented attics must be air sealed at roof deck eaves gables and penetrations.
So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus.
For decades the typical solution to this problem was to install ventilation baffles near the eaves connecting the air space above the soffit vents with the attic and then to install as much fluffy insulation usually fiberglass or cellulose as there was room for between the top plate of the exterior wall and the ventilation baffle.
A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science.
85 minimum to bs en iso 14021.
The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow.
For the same reason insulation shouldn t touch the roof s underside.
Ensure meets any eaves insulation and or internal wall insulation to prevent cold bridge at eaves without blocking any ventilation paths required to loft space roof space.
Flexible formaldehyde free glass mineral wool.
What is continuous insulation.
Install raised heel trusses or use another roof framing method that allows space to install insulation over the top plates of the exterior walls or install high density insulation to achieve an r value that meets or exceeds code minimums for attic insulation.
