To meet all three goals insulating your finished attic ventilating the roof and maximizing headroom use a combination of dense batt insulation rigid foam sheeting and air chutes.
Finished attic no soffit vents.
If you re finishing your attic insulating it to the proper r value can cause a dramatic loss of headroom if you limit yourself to fiberglass batts.
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.
It makes sense that the wettest spots are near the beam because that s the most likely site for humid air leakage from the indoors.
It must also circulate.
The function of soffit vents for proper ventilation it isn t enough for air to simply get into your attic.
For this reason the square footage of vent space at the base of.
However without soffit vents that makeup air comes from indoors a situation that is not desirable in any season.
The answer is rafter venting.
This creates a natural air flow by drawing in the air from outside pushing it up and out through the vent at the top of the house.
This gives you access to all parts of the attic.
The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow.
But building scientist joe lstiburek takes issue with that opting instead for more ventilation at the eaves say a 60 40 split with the eaves getting the greater proportion.
Smart vent a special roof eaves vent product that provides a 3 4 opening about 6 above the top of the roof drip edge.
Place the plywood sheets or boards across the rafters in the attic.
Normal vented air likes to enter the attic lower down near the bottom third of the attic and as it passes through it will exit higher up near the top third of the attic space.
Typically you would have a gable vent on each end of the attic.
This is called passive ventilation.
How to insulate an attic ceiling with no soffit vent 1.
Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no.
Codes require a net free ventilation area nfva of 1 sq.
For the same reason insulation shouldn t touch the roof s underside.
For an attic without soffit vents you may have the option to use gable vents instead.
Figure out how much insulation you need for the area of the country in which you live by accessing the the u s.
I m presuming that the roof has good eave detailing so that rain does not enter at the beam.
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.