A finished attic should be insulated much like the rest of the house with insulation in the walls and ceiling.
Insulated sheathing in the attic.
If there is inadequate ventilation or insulation.
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.
Nick an owner builder pal of mine helped me put up the insulation and sheathing over the course.
Here are four approaches i recommend you investigate for insulating your attic.
How to insulate a finished attic.
Apply a 2 inch layer of spray foam insulation r 10 to r 12 directly to the interior surface of the roof sheathing.
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.
With a finished attic insulation must help keep the attic areas comfortable.
Moving past the ducts i saw that there was insulation between the cathedral ceiling below and the sheathing for the roof.
However this set up causes a different problem.
Box out light fixtures.
This type of ceiling is insulated in the same manner that you would insulate a standard attic space.
On the landing the view of the remainder of the attic was limited by duct work and equipment.
Unless you re using mineral wool insulation or your fixtures are rated safe for contact with any type of insulation don t allow the material to touch or cover recessed cans or lights from the floor below it s a fire hazard.
Installing the attic insulation and roof sheathing went much faster than i had anticipated.
One of the most common reasons to put spray foam on the roofline is to avoid having to air seal the attic floor because the attic is connected with the air in the house and indoor air is more humid than outdoor air which can cause moisture problems.
The wood sheathing on your roof under your shingles can rot or become dry and brittle.
It has been said that insulating with spray foam insulation at the roof line will lead to moisture problems with the roof sheathing.
If you decided to use a rigid foam board to help insulate your cathedral ceiling you would install the board on top of the roof sheathing and underneath the plywood at the top of the roof.
This will keep the surface warm and help minimize condensation.
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.
That means insulating the attic floor only not the walls and having vents in the roof.
Achieving greater r values in exterior walls in exterior walls add insulating sheathing to achieve a greater r value in your wall system.
This will result in having to replace the sheathing and shingles.
Frequently this space is not insulated which is awful for energy efficiency.
