I have been reading some of the archives about houses that are more than 90 years old and have plaster walls. My husband and I have a few questions that need to be answered. First just how easy is it to have insulation blown behind the old plaster wall? Can we do it or do we have to spend thousands for a professional to do it? Also, how will blowing insulation affect the electrical wiring?
Answer:
Blowing insulation in is a DIY project and it will not effect the wiring in any way unless you damage it with the drill as you cut the holes for blowing it in. My system in a house of this age is to drill a hole large enough to accommodate the nozzle at the top end of each stud cavity, drop in a weighted cord to make sure goes all the way to the floor and when I'm satisfied that it does, I blow in the insulation. I do this on all perimeter walls and then cover the walls with 6mm poly for vapour barrier. Now I'm ready to apply drywall so I end up with a smooth, even surface to prime and paint. In cases where the weight doesn't go all the way to the floor, you'll have to measure and drill another hole under the blockage. Plaster has asbestos in it so be carefull and wear the proper masks.
