Insulating an existing wall

An older home may have very poor insulation in the walls.

Lath and Plaster walls may not have any insulation at all.

A seventies home may have had the insulation slough down as described in earlier post or may have had mice damage the insulation to the point it is not as effective.

One way insulation can be added to your walls is to cut holes and blow in foam .

Couple of thoughts about this, it is destructive because it has to be done through out the wall as shown.

Whether done from the outside or inside, somehow the hose has to get into the wall to spray the foam.

So the cost of the repairs needs to be factored along with the cost of the actual job.

This is best done before a remodel.

A link on the actual process.

You will find links talking about the good and bad of this process. The bottom line is you need to look at your particular situation and home's needs.