Two simple alternatives to soffit vents can be installed with little more than a circular saw and a hammer.
Best way to insulate attic without soffit vents.
But if the floor is covered in plywood you can t stuff enough insulation beneath it to do the job sufficiently not even in warm climates.
Insulation radiant and vapor barriers insulating attic.
In an attic without soffit vents you can add insulation in the corners and the wedges between the slope of the roof and the floor of the attic which serves as the ceiling for the room below.
The most common way to add ventilation to an attic is by installing air intakes in the soffits and putting an outlet at the gable of the house.
For homes without soffits or narrow ones the attic can still be very effectively insulated.
Because the simplest and cheapest way to insulate an attic is to add material to the floor.
Sometimes a home without eaves or soffits will use ridge vents.
With old homes it can be very difficult to properly ventilate the attic for a variety of reasons.
The answer is rafter venting.
Plan to pull up the flooring and layer new insulation on top of the old.
This is accomplished by installing insulation to include all of the corners angles and wedges where the attic slope meets the attic floor.
Like some others that have posted i don t have a clue of the best way to insulate this attic.
If i had an older home without soffits i would strongly consider just completely air sealing the attic and adding foam insulation totally removing the need for ventilation.
Rafter vents or insulation baffles install in any rafter space to create narrow gaps that direct fresh air from the soffit vents to the peak of the roof.
Drip edge vents hang out several inches past the edges of the roof allowing you to trim.