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.
Finished attic no soffit vents.
For the same reason insulation shouldn t touch the roof s underside.
Smart vent a special roof eaves vent product that provides a 3 4 opening about 6 above the top of the roof drip edge.
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.
How to insulate an attic ceiling with no soffit vent 1.
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.
For this reason the square footage of vent space at the base of.
It must also circulate.
This gives you access to all parts of the attic.
The function of soffit vents for proper ventilation it isn t enough for air to simply get into your attic.
Of attic space equally divided between eave and ridge vents.
Of vents for each 300 sq.
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.
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.
This is called passive ventilation.
Codes require a net free ventilation area nfva of 1 sq.
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.
The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow.
Figure out how much insulation you need for the area of the country in which you live by accessing the the u s.
Place the plywood sheets or boards across the rafters in the attic.
Venting solutions for roofs with no overhang or soffit install special roof intake venting products that work at the lower edge of the roof decking underneath the first course of shingles.
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.
However without soffit vents that makeup air comes from indoors a situation that is not desirable in any season.
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.
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.
The answer is rafter venting.