The higher the r value the better the thermal performance of the insulation.
Use cool roof or add insulation.
When you find out the r values of your insulation either from an energy assessment the home builder or your own inspection you can then use the home energy saver tool to determine how much insulation you should add and where you should add it for maximum energy efficiency.
Insulation condensation and repairs improper insulation whether the roof is a reflective or dark membrane may cause condensation and will need a repair.
Hack n stack sealed foam board between the rafters would be better since it s at least an air impermeable insulation but even that would require a vent gap below the roof deck to meet code and you d still be under r38 on that 2x6 rafters unless you.
Use caulk and expanding foam the fire blocking type sealant to close air gaps around pipes ducts and electrical wires where they enter the attic.
Add the right kind of insulation.
Staple plastic or foam baffles to the roof sheathing near the eaves to keep the material away.
Cut and fit strips of 24 gauge sheet metal between the masonry chimney and the surrounding wood framing.
Standard or dark roofs can reach temperatures of 150 f or more in the summer sun.
Before installing or adding attic insulation take these steps.
A cool roof reflects the sun s energy reducing rooftop temperatures.
Dark surfaces also contribute to the urban heat island effect.
For the same reason insulation shouldn t touch the roof s underside.
In many cases with a leaking roof just adding a cool roof will repair the roof and waterproof it for decades.
Ultimately attic insulation does help you stay cool in summer.
Every home is different and requires a unique set of fixes.
Use the fire blocking type.
But it s not necessarily an end all be all solution.
Batts between rafters in would require adding ventilation between the insulation roof deck.
The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow.
Cool roofs can be made of a highly reflective type of paint a sheet covering or highly reflective tiles or shingles.
Rigid foam panels are available in thickness.
If you re not getting enough airflow from your ac in upstairs bedrooms adding insulation might only solve part of your problem.
When adding additional insulation you do not have to use the same type of insulation that currently exists in your.
The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type.