Attic Ventilation

[Bruce Hutton]

Hi everyone,
Had an inspection today that had the entire attic insulated
(6" fiberglass batting with a kraft paper face)
This is a complete sealed system with no soffit or roof venting.
Gable end walls & all ceiling areas were insulated.

I expected to find condensation staining but I found none.

Should I be concerned?
Should there be a humidistat type fan installed?
What will this do for shingle life expectancy?

Located in the Mississippi river valley in central illinois.
We get hot & humid here in the summer.

How would you report on this?

[Jim Luttrall]

Hi everyone,
Had an inspection today that had the entire attic insulated
(6" fiberglass batting with a kraft paper face)
This is a complete sealed system with no soffit or roof venting.
Gable end walls & all ceiling areas were insulated.

I expected to find condensation staining but I found none.

Should I be concerned?
Should there be a humidistat type fan installed?
What will this do for shingle life expectancy?

Located in the Mississippi river valley in central illinois.
We get hot & humid here in the summer.

How would you report on this?

No vent fan to outdoors with or without a humidistat should be installed.
Shingle life as related to temperature has been shown to be more affected by the shingle color than attic ventilation.
I would be concerned by the exposed paper backing.

[Jerry Peck]

Deserves repeating.


I would be concerned by the exposed paper backing.

That is important -fire could spread over the face of that insulation in very little time.

[mark tyson]

Hi everyone,
Had an inspection today that had the entire attic insulated
(6" fiberglass batting with a kraft paper face)
This is a complete sealed system with no soffit or roof venting.
Gable end walls & all ceiling areas were insulated.

I expected to find condensation staining but I found none.

Should I be concerned?
Should there be a humidistat type fan installed?
What will this do for shingle life expectancy?

Located in the Mississippi river valley in central illinois.
We get hot & humid here in the summer.

How would you report on this?

Unvented Attic assemblies. Unvented attic assemblies shall be permitted if all the following conditions are met:
1) The unvented attic space is completely contained within the building thermal envelope.
2) No interior vapor retarder is installed on the ceiling side (attic floor) of the unvented attic assembly.
3) Where wood shingles or shakes are used, a minimum continuous 1/4" vented air space separates the shingles or shakes from the roofing underlayment
4) One of the following shall be met, depending on the the air permeability of the insulation under the structural roof sheathing:
a) Air-impermeable insulation only. Insulation shall be applied in direct contact to the underside of the structural roof sheathing.
b) Air-permeable insulation. In addition to air-permeable insulation installed directly below the structural roof sheathing, at least R-5 rigid board or sheet insulation shall be installed directly above the structural roof sheathing for condensation control.
c) Air-impermeable and air-permeable insulation shall be applied in direct contact to the underside of the structural roof sheathing for condensation control. The air- permeable insulation shall be installed directly under the air-impermeable insulation

[Robert Hronek]

I see that the attic floor is plywood. Is there insualtion under the plywood? What is the level of attic insualtion?