Blown-In Fiberglass over Old Existing Batt Insulation in Attic
jbrammer14
| Posted in General Discussion on
The house is 40 years old. Existing insultation has fallen away from attic walls. Contractor recommends new layer of blown-in fiberglass to R-38 level.
1) Should old insulation be removed prior to new blown-in fiberglass layer on attic floor?
2) If existing insulation is dry/pest free does that affect decision?
Replies
If the existing insulation is dry and pest free you can add more on top.
But there is a lot to be said for removing the 40 year old stuff first.
first question is how you know, without removing, that the entire attic floor is pest-free?
There likely is a couple re-roofs of dust and dirt on top of the insulation.
This also would be an ideal time, with the old stuff removed, to seal up any penetrations in the wall tops and ceilings, and to closely inspect wiring that becomes visible.
I’d definitely remove the old, vacuum, air seal lights and use cellulose instead fiberglass. The air in your attic mingles with the air in your house so keep it as fresh as possible.