Moisture escaping through the interior walls can condense inside the insulation creating a saturated area within the insulation. Some fear that that will lead to nasty structural problems. I don't know as I have no insulation in my walls, as they are almost solidly filled with several layers of between wall "studs" with lath and plaster.

What did you do about a vapor barrier when you insulated the attic?

If you were tearing out your plaster/sheet rock you could install over a vapor barrier and prevent the problem. (I personally wouldn't tear out old, intact plaster just to do this, however.) Alternatively there are some paints which are supposed to prevent vapor transmission. I think most paints do to some extent, and some under-wallpaper liners, as well.

Of more importance is whether you have knob and tube wiring which should NOT be surrounded with material as it needs air to stay safely cool.

And I'd also be wondering if the insulation can truly get everywhere within the walls, particularly around intra-wall pipes chases.

Molly

Am currently just starting to work w/ a weatherization specialist. His preliminary advice is that it depends on the installer. Lots has been learned about the installation and makeup of the insulation over the past 30 or so years. He says ('course he would), that if the installer knows what s/he's doing, then there's no problem w/ blown in insulation. The difficulty is making sure that the areas around outlets, etc. are filled.

We're getting an energy audit done on our house early next week. I'll know more about this whole process and will be happy to pass along what we learn.

It may be worth having this done first, as it can help pinpoint where the majority of leaks are occurring. Your local energy company provider (even if they don't know it) can point you in the direction of energy audits. Ours will cost $200, which is a bargain when you consider what natural gas costs are going to be this winter.

Knob and tube, btw, as long as its sheath is intact, is like any other wiring and can be safely insulated. The thing is, you don't know whether or not that sheath is intact. Likely, if it's in your walls, it is. This comes from lots of convos w/ electrical inspectors; it's not my opinion.

However, if you are planning on upgrading wiring, it's best to wait until to insulate because (1) it's easier to wire w/out the void filled and (2) you want the insulation as densely packed as possible, which won't happen if you have to move wiring around.

Major concern developing about removal and replacement of the old clapboard siding. How does one not destroy it?

As I understand it, they remove single courses of clapboards and drill a hole in the sheathing which is then plugged and the siding is nailed back on.

Right, according to the group who did our audit last week. Years ago, when my mother had her house done, they drilled holes in the siding and then plugged them back up. When the house was painted, you couldn't really tell that it was done unless you were close.

Now apparently, you should look for someone who can take off the clapboards, stick a hose in there and blow in the insulation and then put the clapboard back on.

Yrs ago before my sister owned her house, my husband and I rented it. Our heat bill was over the top and the landlady had insulation blown in from the outside. The house had aluminum siding and the holes were plugged (white siding with white plugs that have turned yellow). Now that my sister owns it, she's had to gut a couple rooms because of the plaster falling apart. Or in the bathroom, the cheap paneling was installed using the liquid nails stuff, so plaster came off when she was removing it. Anyway, the blown in stuff was still packed and dry. When we bought this old house last Dec. I knew there was no insulation in here. My dad and I did it from the inside. We drilled 1" holes in outside wall rooms, and under windows. The holes were easy to patch using plaster the contractor left behind. I did run out of the plaster and used joint compound in a few areas. We felt doing it from the inside was making us sure where it was and where it wasn't. I had to gut our kitchen. After gutting it, I saw in 1 little corner they had blown in insulation from the outside. It was a real hit and miss job. Blowing in the insulation was also one of those jobs I knew I could do myself with the help of my dad and I'd rather do it myself than to pay someone.

I would think that you'd get alot blown back at you with the whole piece of siding taken off? I had to have a new ceiling in the foyer and there was a gap between the old plaster and new sheetrock. Trying to blow in, in this area, we had to get creative. We cut cardboard and taped it up. Otherwise, all the insulation just blew back in my dad's face.

I have a ballon frame house vintage 1911. About 25 years ago I had the walls insulated with blown in fiberglass insulation. I have experienced no problems with moisture in the walls. Be sure that your crew is experienced with old houses with plaster walls. When they started my job, they used too much pressure and caused a plaster/lathe wall to bulge out in one room. After adustment, everything was fine afterwards. Also, a ballon frame is typically open from the attic to the basement, unless fire stops have been installed. You can pump insulation for quite awhile before realizing it is blowing out in the attic and basement. Also, be carefull near the house corners as usually there are angle braces to help the framing withstand wind loads.

How can one tell if the installer is successfully dense packing, or if spots are being missed, as it's being blown in?

As far as I know, the only way is with a post-insulation inspection via infrared camera. Some electric and gas companies offer this for free or reduced fee.

Am not sure it's being done right. They drilled a hole about 18" from the sill, and 12" from the top of the house. Dropped a stone down to check for obstructions and plugged the hose in the bottom holes and filled. Then they stuck the hose in the upper holes and filled. It's a two story house -- should they have drilled in the middle are as well?

Took about 120 seconds total combined top/bottom filling for each cavity to fill.

Was surprised to see that some of the stuff blew into the basement through the ceiling.

Is Sep 18 of 2011 ans after i read all this post i just have a curious question? where can i find someone reliable to do this type of work? And also, what will be the best material to use?