Mark the ends with a square.
How to drill hole in attic at roof.
And use semi rigid wiring fish tape to pull your wiring down to your outlet location.
Cutting drywall and drilling from below may be the only option if you have to access the attic there.
Place all the roof vents on the same side of the roof.
Cutting ventilation holes using a chalk line mark the parallel lines for the opening of your vent.
Down the attic ladder we went climbing up the roof ladder to find our drill bit like little kids hunting for easter eggs.
Position the vent pipe up to the bottom of the roof.
Mark the roof venting locations from the attic where you can see the rafters and avoid placing roofing vents over them.
Where the scrap wood hit the understructure of the roof we drilled a hole straight through to the outside.
If you will need to fish wiring through a wall drill a hole through the wood plate in the attic only.
The penetration will be oval to have a round pipe exit vertically through a pitched roof you need an oval hole in the roof.
Standard practice is to drive a nail through but my friend was heart set on using a drill.
With the pipe in a vertical position trace around the pipe using a pencil.
Use a drill with a hole saw bit of 1 inch or more to start your hole then use a power saw such as a jigsaw or reciprocating saw to make the cuts in the soffit.
Don t cut into any rafters.
When cutting through drywall from the interior of a room use a utility knife and cut carefully you don t want to drill through a hidden wire or the paper backing of the attic insulation.
Go into your attic.
I did this recently to run ethernet cable in an exterior wall.
Mark the hole with chalk and set your saw depth to cut through the shingles and the roof sheathing only.
An alternative is to drop all the way through the wall cavity from another top plate in the attic and into the basement or crawlspace then run over to the wall you want to end up in.
Below the peak of the roof.
Cut a square hole in the roof the same size as the hole in the base of the vent you re installing.