Five common causes of poor attic venting.
How to apply attic insulation at eave space.
Design the roof to allow full insulation over the top plates of the exterior walls.
With a finished attic insulation must help keep the attic areas comfortable.
Space stay wires about two feet apart.
Apply a 2 inch layer of spray foam insulation r 10 to r 12 directly to the interior surface of the roof sheathing.
Install raised heel trusses or use another roof framing method that allows space to install insulation over the top plates of the exterior walls or install high density insulation to achieve an r value that meets or exceeds code minimums for attic insulation.
You can then apply batt insulation around the foam without worrying too much about the air space.
I ve been in plenty of these homes and can tell you that when spray foam is installed properly they outperform 99 of fiberglass batt insulated stick built homes.
A finished attic should be insulated much like the rest of the house with insulation in the walls and ceiling.
Homes insulated with it can be some of the most efficient and comfortable homes built.
For diy attic insulation you ve got two choices.
Install air chutes or clear them if they re clogged photo 1.
How to insulate a finished attic.
Both can be added to uninsulated attics or layered over existing material.
That means insulating the attic floor only not the walls and having vents in the roof.
Aluminum or vinyl soffits eaves installed over plywood soffits that don t have venting holes.
Once you ve decided which type is best for you examine the material options and prices to home in on the right product.
Secure the insulation using stay wires.
Loose fill or batt the common term for blanket insulation.
This will keep the surface warm and help minimize condensation.
Insulation often clogs the space between the rafters blocking air from traveling to and from the soffit area.
Spray foam insulation is a great product.
For decades the typical solution to this problem was to install ventilation baffles near the eaves connecting the air space above the soffit vents with the attic and then to install as much fluffy insulation usually fiberglass or cellulose as there was room for between the top plate of the exterior wall and the ventilation baffle.
Press the wires up against the insulation and the pointed ends of the wires will dig into the joists holding the insulation in place.