Adding insulation to walls with existing fiberglass insulation in them?
Jeremy Radigan| Posted inEnergy Efficiency and Durabilityon
Adding insulation to walls with existing fiberglass insulation in them? Walls of our house on the lower floor are cold to the touch, yet they do have insulation in them. Is it possible to add more?
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Replies
Jeremy,
The usual method of adding insulation to a wall which is already insulated is to add exterior rigid foam. Of course, this method requires you to remove the existing siding. For more information on this method, seeHow to Install Rigid Foam Sheathing.
It's also possible to add a layer of exterior mineral wool. For more information on this method, seeWrapping an Older House with Rock Wool Insulation.
Finally, it may be possible to drill one or more holes in each stud bay (either from the exterior or the interior) and to try to blow some additional cellulose insulation in the walls, thereby compressing the existing fiberglass batts. This approach can be technically tricky, and may not be worth the considerable hassle. Some cellulose installers may be willing to attempt it, while others will probably decline the challenge.
One more point: the reason that your walls feel cold may have as much to do with air leakage as insufficient insulation. In a house that feels cold, it's almost always a good idea to hire a home performance contractor to perform blower-door-directed air sealing.