sawdust for insulation

Discussion in 'Homesteading Questions' started by bob clark, Aug 25, 2006.

  1. bob clark

    bob clark A man's man

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    I am working on building a shack to live in that is of pole barn construction. the walls will have a void of about 10 inches that can be fulled with insulation. I was thinking of useing sawdust since i can get it for free.

    I am not worryied about the fire hazard this may be as it will only be me in the house. no wife or kids to burn up.

    I thought about bugs. could i put an insectiside in the sawdust to eliminate a bug problem? what cheap insectisides would work? I have access to about a ton of wood ash as well.would it keep bugs out of the sawdust? or would the acid in the ashes do more harm to the lumber in the house than the bugs would?

    I also have tons of free switchgrass and access to a grinder

    I have to do this on the cheap as i have no job and dont want to go on the govt doles. yea I know ,pride is a sin

    any ideas? I know there are some skin flints out there. what would you do?
     
  2. sancraft

    sancraft Well-Known Member

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    I'm interested to hear this answer. Our cabin needs insulation bad.
     

  3. bob clark

    bob clark A man's man

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    hey lady, sorry to hear of your trouble down there

    how about a big cyber hug from an old fat guy?
     
  4. big rockpile

    big rockpile If I need a Shelter

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    I wouldn't use it.If its not dry enough when put in or gets wet,it will get way too Hot.

    big rockpile
     
  5. tooltime

    tooltime Border Ruffian

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    Bob,

    I think one problem you'd have to deal with is keeping air and moisture from getting into the sawdust, or you're likely to get a mold problem.

    What were you thinking of using as interior wall material?

    I know that in some of the cordwood construction, they use sawdust and mix in slaked lime to keep out the pests, but in cordwood construction you've got mortar on each edge of your cordwood wall which is supposed to seal out the air and moisture.
     
  6. Lionrose

    Lionrose Well-Known Member

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    My partner gets it free at work, brings it home by the (huge) bag full. But it isn't dust, but rather shavings. Pine and cedar.

    I plan to use it to insulate the chicken house I am going to build as soon as I get all the materials gathered up. Been working on tearing down an old oak barn for the lumber (but shucks a lot of it is to nice to use on chicken house).

    Cedar is a natural bug repellent and I am hoping if I mix it with the pine 1/2 and 1/2 it will be enough to keep any bugs out. I'll do the chicken house with it to see how it dose. Then I'll know if I can use it to insulate a small cabin I want to build on the property.

    Is your sawdust by any chance cedar or cedar mix? If so I would say yes. I would use it to insulate with but that’s just my peon opinion. :rolleyes:

    Rose
     
  7. bob clark

    bob clark A man's man

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    I wouldnt have any problem making sure it was dry enough when it went in, but i can see how it would heat up if there was a leak in the roof that went down the wall

    is there any thing that could be added to inhibit the heating process?
     
  8. bob clark

    bob clark A man's man

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    the walls will be of plywood and a rough cut oak. the sawdust is cotton wood,oak,and maple for the most part
     
  9. bearkiller

    bearkiller Well-Known Member

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    As mentioned earlier, lime can be added to the sawdust as it is done with cordwood structures. What you see by doing this is the moisture reacts with the lime to create a more or less solid insulation. I mean the lime + water results in a setting up of the mix. Huge benefit this way.

    Sawdust alone over time simply decomposes slowly and you are left with mold in the walls and no insulation. I know, I've done it!

    bearkiller
     
  10. ericjeeper

    ericjeeper Well-Known Member

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    It is an old building the cellar ceiling and walls are packed full of sawdust. I am guessing It works well. It has not burned down due to any moisture issues.
     
  11. bob clark

    bob clark A man's man

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    how long do you think sawdust with the lime would last? I am looking for the shack to last me about 15 yrs, 20 on the outside
     
  12. The Paw

    The Paw Well-Known Member

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    There are lots of old buildings up here that used shavings and sawdust for insulation, but the winters have very dry air up here, and there are no real termite issues. A good vapour barrier and a tight roof might help keep it dry. As bearkiller says, over time sawdust will settle leaving gaps at the top of the wall.

    I have read that they mix Borax in with blown cellulose insulation to prevent bugs from nesting in it. I have no idea how much, or how to keep from breathing the stuff in if you use it.
     
  13. bob clark

    bob clark A man's man

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    thanks for all the good posts all :)
     
  14. DrippingSprings

    DrippingSprings In Remembrance

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    I dont see why you cant use it. I have blwon insulation between the studs in a wall many times. All it is is ground up newspaper with borax added into it as a flame retardant and pest diverter.

    You can buy 25 pound bundles of the cellulous(finely ground newspaper treated with borax) for about ten bucks. Youd be amazed how far that much will go if your just sticking it between the studs. Its what all the major mobile home manufacturers use now.

    Sancraft you could do this easily with your place and it would be cheap compared to most other routes.

    Bob Im thinking you could get one of those lil pump sprayers and mix you up some borax and wet that sawdust good and then let it sit and dry. Of course mixing it up as it dries and it would be just as safe as the cellulous insulation. After drying just stick it in there.

    You can rent a insulation blower for about 30-50 dollars at rental places.
     
  15. bob clark

    bob clark A man's man

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    I have a friend that i have done plenty for in the past that has a blower he would prolly let me borrow. would a blower work good with saw dust?
     
  16. cc-rider

    cc-rider Baroness of TisaWee Farm Supporter

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    I just read the Menards ad and they have 25# bags of cellulose for blowing for $5!!! And the blower rental is free. Each bag supposedly does up to 75 square foot, depending on how thick it is. Really, you can't beat that. I've even done it before and it is easy to do.

    If you are absolutely broke, though, go buy a bag (or maybe the minimum is 5) to get the free rental of the blower. Blow the cellulose, and then use the blower to blow in your sawdust. Or mix them together??!?!?!
     
  17. ckncrazy

    ckncrazy Well-Known Member

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    I dont think that is a good idea for the chicken's. Ceader can cause respitory problems with them.
     
  18. MorrisonCorner

    MorrisonCorner Mansfield, VT for 200 yrs

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    Sawdust is dusty... which creates a potentially explosive situation as airborne dust particles are flameable. There is also the issue of mold, settling, and, if the stuff starts composting, rot and.. if it gets hot enough, spontaeous combustion.

    Bob, you're usually pretty sensible, but it seems to me like you're posting this in hopes that someone will say "go for it" which will allow you to discount all the negatives. This is bad thinking. Sawdust is a cheap byproduct of wood manufacture. If it made half way decent insulation it would be used in the industry as insulation. It isn't, it doesn't, and it represents a significant health hazard.

    My home was originally insulated with hay and newspapers. You haven't lived until you've had to pull that mess out from the walls. I'm not celulite stuff... also a very bad choice for a long term job but it does blow into old houses. I think my house would be better off if it had a proper vapor/wind barrier and NO insulation. Invest in a high quality vapor/wind barrier and siding and leave your studs open for the winter. You can keep the temp up with a wood stove and insulate as you go.
     
  19. Boleyz

    Boleyz Prognosticator, Artist

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    I know free sawdust may seem a better option than cheap cellulose, but here's my thoughts...

    Sawdust has always been plentiful, yet has never made it into commercial use like fiberglass and cellulose for insulation. There's probably a reason why, since you're not the first to think of it as is evidenced on this board.

    Cellulose and fiberglass have naturally occurring air cells. I would imagine that sawdust, poured into a studspace would tend to pack down pretty tight and solid at the bottom.

    In such a situation, the lack of larger air cells would allow for even the miniscule amount of moisture from humidity to begin the process of mold and rot.

    I'm not sure such a shack would be healthy to live in. JMHO, but something to think about.

    Generally speaking, my thoughts would be that if it was reasonably feasible, someone would have sawdust insulation on the commercial market.
     
  20. minnikin1

    minnikin1 Shepherd

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    Maybe you can find a local sheep shearer. Lots of folks raise sheep and don't keep the wool.
    Sheep wool is an EXCELLENT insulator, safe, healthy, slightly fire resistant.