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Community and Q&A

How should I fix no wall insulation?

bwsct | Posted in General Questions on

My house built in 1953 has no insulation in the walls and I’d like to do something about it.  The exterior is cedar shake siding with tar paper underneath and also in need of a paint job or possibly vinyl siding.  I will also need to replace the windows at some point.

I’m looking for recommendation on how to insulate.

Would I better off insulating with blown in cellulose from the outside or tearing off the exterior siding and putting up a foam board insulation?  Or is any of this just a bad idea?


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  1. GBA Editor
    Martin Holladay | | #1

    First, you have to decide whether you want to replace the siding. If you are replacing the siding, it makes sense to insulate your walls from the exterior -- for example, by installing dense-packed cellulose between the studs and a continuous layer of exterior rigid foam.

    Two relevant factors are your climate zone and your budget. Investments in insulation have a faster payback in Minnesota than in Alabama. And every homeowner has to consider their budget when planning an insulation retrofit job.

  2. bwsct | | #2

    HI Martin,
    I'm in southern Connecticut.

    I'm trying to determine what the best way is to insulate and not dead set on replacing the siding since it is in good condition other than needing painting but will replace it if I need to.

    I've heard people say that dense packed cellulose settles. Is it ever a good idea to gut the sheet rock or in my case plaster walls and insulate from the inside?


    1. Expert Member
      Akos | | #4


      No need to remove the interior walls. You can blow in cellulose through a 4" hole cut in the drywall/plaster and patch it afterwards. My preferred method is to cut a 4"x10" square right across a stud. This way you can insulate two stud bays and patch only one hole.

      In your case it is probably easier to take off a couple of cedar shakes and dill a hole through your sheathing to blow in the insulation.

      If the insulation is not packed well enough there could be some settling. Even if there is, the wall will insulate WAY better than it did with no insulation, so I wouldn't worry too much about it.

      Before you start, check and fix your window/door flashing. Insulating with leaky windows is a recipe for moldy insulation.

      1. bwsct | | #6

        What would you do knowing the house needs a paint job and also insulation?

        1. Expert Member
          Akos | | #7

          Sometimes insulating older building causes paint issues on siding. This happens on houses with clapboard directly over studs without WRB or sheathing. It doesn't sound like the case with yours, but you might still end up with paint issues after insulating.

          My $0.02 would be to insulate the walls, wait a year or two and if you have no paint problems refinish the siding. If you end up with paint problems than install new siding over the shingles.

          I've done DIY semi-dense packing cellulose with the blowing machine from the box stores. Just have to make an adapter (I used a series of car exhaust pipe reducers) to connected a 1.5" hose to the large hose that comes with the machine. Not as good as a proper dense pack, so far no noticeable settling in two years.

          Generally there is little financial payoff for doing more insulation than just filling the studs.

    2. Expert Member
      Dana Dorsett | | #11

      >"I've heard people say that dense packed cellulose settles."

      You've heard wrong, or those people are wrong.

      At 3 lbs per cubic foot or higher DENSE packed cellulose will not settle in your climate. The ~2 lb density 2-hole method cellulose can settle a bit over time, but even that isn't a significant issue in typical 1950s framing (compared to multi- story balloon framing.)

      If you're still not convinced, blown fiberglass at 1lbs density or higher won't settle, but hold out for 1.8lbs minimum density dense packed. The 1lb stuff isn't very air retardent, whereas 1.8lbs density is air retardent, and installed at a high enough pressure to pack fiberglass into all the leak paths, tightening up the house considerably.

      Gutting the interior isn't necessary. As long as the wallboard or plaster is in reasonable shape and the nails haven't rusted into thin crumbly tacks it's possible to install even 3.5lb cellulose or 2.2lb fiberglass through a single 2"- 2.5" diameter hole in the wallboard in each stud bay. Plaster & lath is usually more robust than wallboard. I've personally installed 3.2lbs cellulose from the interior in ~95 year old horse-hair plastered walls without a hint of blow-out, cracking or bowing. The time and effort it takes to repair of the holes will vary, but if the holes are drilled with a hole saw (pretty standard when installing from the interior) it's not a big deal.

      1. bwsct | | #12

        Hi Dana,
        Do you know if any Green building contractors in CT?

  3. spenceday | | #3

    I’m about to do dense pack in my walls on a 1953 ranch.
    Loose fill fiberglass or cellulose will settle, dense pack should not. I’m drilling from the outside and removing a course or two of shingles prior to drilling. You can also drill from the inside and refinish the walls

  4. Expert Member
    ARMANDO COBO | | #5

    You could use injected spray foam into the wall cavities. Peter Yost wrote an article on BuildingGreen back when he was much younger ;)). One Thing Peter does not address in his recommendations is to have a IR camera on site to "see" where all the stud bays are so you can get a complete wall cavities installation.
    Spray foam can cost more, but you can save overall by not removing plaster.
    See Peter's article:

  5. bwsct | | #8

    Can someone recommend how I can find Green building re-modelers in my area? I'm in CT.

    1. GBA Editor
      Martin Holladay | | #9

      GBA maintains a Green Building Bulletin Board that lists contractors, but we don't have any listed contractors in Connecticut -- at least, not yet. Perhaps a GBA reader can help.

    2. bfw577 | | #13

      Southern CT resident here. Have you gotten a free energy audit done from Energize CT yet? It cost $149 and includes up to 1k in services. Its subsidized through charges on electric bills.

      I had one done and was amazed at the amount of work the crew did. They did a blower door test, tested the static pressure of my duct work, used IR cameras to look around etc.
      They spray foamed tons of cracks, insulated pipes, put mastic on all my duct work seams, etc.

      At the end they give you a list of eligible rebates for work all the work. They are extremely generous towards insulation upgrades. I think I got like $800 towards insulation in my basement. They also had one for a free wifi programmable t-stat. The fund has a ton of money as not many people get the audit done.

      1. bwsct | | #14

        I've had an energy audit done and they did many of those things. I think some of my projects are more intensive and I need someone knowledgeable to help me move forward.

        My house has cedar shake siding and lead paint so I need to decide to have an expert strip and repaint or remove the cedar shake and install vinyl. I also need to add insulation either just dense packed cellulose or a combination of that and rock wool or rigid foam.

        Most contractors have very little knowledge of the right way to do this and I either do I.

      2. bwsct | | #15

        Can you tell me which company performed energy audit for you?


  6. user-6623302 | | #10

    Check out the state energy saving programs. Cheap advise and screened contractors. Having done a lot to my house, I learned the hard way that you need a long range plan. Knowing what I know now, I would have done things different.

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