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Basement Insulation Question

Post in 'DIY and General non-hearth advice' started by homebrewz, Nov 23, 2008.

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  1. homebrewz

    homebrewz Minister of Fire

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    Another basement insulation question. I've reviewed several of the basement insulation threads here, but most seem to be concerned with insulating walls to keep the heat in from a stove. My situation is a little different. I'm in an 1860's farm house with two big rooms that make up the basement, and two above that which make up the first floor. In the basement, the sills and the walls are uninsulated. I'm heating the first floor with a wood stove in one room (into exterior masonry chimney with an insulated flex liner, block-off plate, etc) and the other side of the house is heated with a pellet stove.

    The floor of the first level can be quite drafty at times. I suspect that the heat on the first floor is helping to encourage drafts from the basement. The floor on the first floor is an old wood floor and occasionally there are slight gaps in between the planks that let cold air into the living area. I know I can add some insulation in the basement to help this, but I'm wondering what I should do. Insulate the sills? Insulate the basement ceiling? If so, should I use foam board or fiberglass bats? I heard from someone that sealing up a sill plate may encourage moisture and rot problems.. is this true?

    I was also thinking about applying a clear caulk or silicone in between some of the problem boards of the wood floor to keep out drafts.

    Any advice would be much appreciated. Thanks!

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  2. dbjc364

    dbjc364 New Member

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    you wont get any moisture-rot problem if using "Foil-Bubble foil" Radiant Barrier. Its my understanding, if you want to keep the floor of your livng space warm- dont insulate the floor-basement ceiling??..just the walls & foundation..?
  3. webby3650

    webby3650 Master of Fire

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    It seems that the best way to tackle your problem is to stop the cold air from infiltrating your basement at it's source. Be careful using fiberglass insulation, it is a favorite place for rodents to nest and tunnel.
  4. velvetfoot

    velvetfoot Minister of Fire

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    I imagine your basement walls are made of rocks and probably leaks?
    It'd probably be futile to insulate the basement walls.
    I think I would get an estimate on foam spray insulation.
    It would seal the gaps, including out to the sill area.
    Then, if you wanted more insulation, you could put in unfaced fiberglass batts.
    I'm totally not sure, but I think the fiberglass might qualify as a fire retarder (or whatever it's called) if the foam needs it (again, I don't know).
  5. ozzy73

    ozzy73 Member

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    My neighbour has a rouble foundation with dirt floor built in the 1850's. He was not able to insulate it with batting/sprayfoam either.
    He ended up using a moisture sealing compound on the foundation and sealed the sill plate with spray foam. That did the trick for him.

    Seal up every little nook and cranny with spray foam to prevent airfrom comming into the basement.
  6. billb3

    billb3 Minister of Fire

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    sill plate rot is usually from open concrete blocks,
    Or wet fiberglass stuffed into gaps that ca get wind driven wet.
    best to seal from outside if you can.
    low expanding foam.
    one trick for gaps big enough for mouse entry is to fill with copper scrub pad (steel rusts away) then foam over. Mice will chew through the foam covering a hole they got through yesterday, but not copper.

    many older houses have no insulation between the joists at the rim joist (if there is a rim joist). Best insulator for there is that rigid solid closed cell foam cut slightly smaller to fit between the joists and held in place with low expanding foam. Some codes want the foam (or any insulation) covered with drywall, soem insist on it being removable for termite and rot inspection. Look for mice holes into the wall cavities above while you're there.Bloch the holes with tin or copper. There are boulevards to the attic and any nice warm chimney cavities.

    Some of those old wooden cellar windows can be drafty as a screen.
    A exterior storm window for them can help. Justt a acrylic plastic window picure framed in is fairly inexpensive, may be the only solution for odd sized windows.

    Even little things like over size pipe holes can allow entry for mice and wind.


    Rigid foam and spray foam for stopping wind.
    Fiberglass and cellulose fill for heat loss.
  7. homebrewz

    homebrewz Minister of Fire

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    Thanks everyone for the replies.

    dbjc364: Are you referring to the stuff that looks like industrial strength bubble wrap with a foil backing? I've heard that stuff has a very low R value?

    Velvetfoot: Yes, they are rock walls, some of which have been sealed over with a cement. There is only one area that sometimes gets wet when the ground is
    saturated.

    I think I'm going to start by sealing up the drafts coming through the floor with a thin bead of silicone in between problem planks. Then later on I'll try the foam board in an area of sill and see how that goes. My main concern was inviting moisture issues.
  8. dbjc364

    dbjc364 New Member

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    It appears that we're having as many problems with cold floors & drafts as you are. We have wood floors here too.We only have 2 "real walls"- which we strapped first with 2x2's,have the "air gap",then the "Radiant Barrier".This cellar has not seen any insulation since being built in 1932.What very little bit was stuffed up into the sills-?, was old-damp & rotting.Yes- the Radiant Barrier is a Foil-Bubble Foil",tough stuff-very easy to work with,no itch or mess.We chose that for those reasons,and it was better than having nothing at all.Moisture or pests don't bother it. Up in the little cavities-sill area,I think we'll try styrofoam pieces cut to fit maybe-and I know Jim does not like dealing with the spray foam stuff. This year we are using plastic around the foundation again,& mulch hay.2 winters ago- when we used the hay-that was our best year for decreasing the amount of gallons of oil by 200. Thats a noticeable decrease.We take it away & throw it in the field in the spring, the cost is roughly $50,if we go all the way around.So I got to say that the hay is about the best thing for keeping out the wind especially, as we get hit front on from the mountains. The hay completely covers the foundation all the way around. Its just a bit time consuming in the spring-but now we have the small tractor to do the brunt of the work. We refuse to buy any more than a total of 200 gallons of oil this year-have the pellet stove in the living room-will use no more than 3 ton,I know we will have some of one or the other left over. I prefer to burn up the oil-instead of paying to have it pumped out-as we are getting rid of the oil tank hopefully next year. This house will be all done using oil,so now we are trying to decide if anything at all is needed in the cellar after we get it all insulated. Besides the 2 "real walls" the rest is rock crawl space. Styrofoam boards in one section have held up very well for our 5 yrs-except for the mouse that keeps making holes under it..Right now we have a temporary propane heater down there-haven't used it yet-its maintaining 45*-58* with using no heat,so its very possible we don't need any thing at all- as long as we continue to insulate well.I personally,,am on the "Warpath" against these two utility bills,with the light bill being just as important,and hopefully we will figure out what the heck is causing the bill to be so high each month since we have lived here for 5 years- and everything is 5 yrs. old or newer. We've just purchaseed the "Kill-a-Watt" machine to find the dastardly culprit. Our household of 2,is the same as other peoples lifestyles we've checked- and we're twice as many killawatts every month..and that has really got me wound up tighter than a porcupines butt. This morning, we start building our 1st "Solar Air Collector"- and running around with the Kill-a-Watt machine.When I get these 2 bills to an acceptable level, then I can see the deck being built on back- and the kitchen remodel happening. Until then its only a pipedream...
  9. homebrewz

    homebrewz Minister of Fire

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    Don't pay to have your old oil pumped out. Put an ad out in the free section of your local craigslist. I'm pretty sure someone will take it. You might even get them
    to take the tank. I had a friend switch to NG and I was more than happy to come and collect the remaining 80 gallons of fuel oil blend that was left behind.
  10. PaulRicklefs

    PaulRicklefs New Member

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    Standard basement insulation standards for a masonry or concrete foundation wall in my area (northern saskatchewan) would be to first vapour barrier and seal over the existing wall using acoustiseal or tuck tape, then build a 2x4 or 2x6 wall (thicker the better) with fiberglass bat insulation. then vapour barrier again, then drywall over that. You will have a very moisture tight wall that will hold the heat in wonderfully. Seal up any overlaps with acoustiseal and make sure you seal to any windows or openings to prevent drafts. Also insulate and seal between the floor joists. I think you will be very happy with this type of install and it will certainly reduce your heatload.

    If you decide to use spray foam or rigid foam insulation, just remember that that stuff burns very easily and you will need to make sure it is covered up with drywall immediately. Great products but very dangerous if not completely covered up. I prefer fiberglass because it's much more fire retardant and won't give off toxic fumes like foam will.
  11. Cluttermagnet

    Cluttermagnet Minister of Fire

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    That's true. I've been just starting to learn about burning waste oil. Leftover number 2 fuel oil would be eagerly sought after. Those guys even burn used motor oil and vegetable oil from fryers, etc. Some waste oil users will get a second tank to use for filtration and allowing sludge to settle out of the waste oil.
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