If a skylight is installed in the roof over an attic a shaft must be built to connect the skylight with the ceiling underneath.
Skylight insulation attic.
That means insulating the attic floor only not the walls and having vents in the roof.
With a finished attic insulation must help keep the attic areas comfortable.
Because the shaft walls separate the interior of the house from an unconditioned attic it s essential that they be well insulated.
Learn how to insulate a skylight shaft here.
How to insulate and air seal skylight shaft walls.
If a skylight shaft contains an air permeable insulation such as cellulose or fiberglass the insulation should be enclosed on the attic side to create an air barrier.
How to insulate a finished attic.
Materials for a skylight are fairly basic especially in the attic.
Inspect the existing skylight for signs of water leakage such as water stains and rot.
These range in price from 150 500 for a 2 x 4 ft sized skylight.
A different type of insulation will need to be installed along the skylight shaft walls one that will maintain both the full alignment or contact with the back side of the sheathing for the height of the skylight shaft walls and at least.
A finished attic should be insulated much like the rest of the house with insulation in the walls and ceiling.
Repair skylight flashing from the roof exterior and replace any damaged framing as necessary.
Rigid foam is the optimal choice for an attic.
Skylight shaft walls are sometimes vertical but more typically they are sloped to create a splayed opening.
However these kits are for use with asphalt shingles.