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below ground foundation

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  • sarakrohn92
    I saw an article in the past 5 years ? about a bale house, built by perhaps a tile maker, perhaps off the grid, with a foundation that was 18 inches below
    Message 1 of 5 , Mar 1 8:48 AM
      I saw an article in the past 5 years ? about a bale house, built by
      perhaps a tile maker, perhaps off the grid, with a foundation that was
      18 inches below ground, so they stepped down into the house. Around
      the perimeter of the house they also had an insulated slab,
      approximately 2 feet or so (imagine a narrow sidewalk.) The foundation
      wall extended above ground to keep the bales dry, away from the snow:
      I'm not sure how high it was. I thought I saw this in Dwell Magazine,
      however I cannot put my hands on it. It is not the straw bale dog trot
      featured there.

      I think this concept is from Sweden, but when I look for foundation
      plans from Sweden I have not found the specific plan for putting the
      floor of the house 18 inches below ground. Can anyone help me find a
      drawing or article of this type of foundation?

      thank you.
      sk
    • RT
      ... Sara; You describe something like the main floor level in my own home. The foundation is basically just a stem wall foundation whose footings extend to
      Message 2 of 5 , Mar 2 4:33 PM
        --- In SB-r-us@yahoogroups.com, "sarakrohn92" <sara@...> wrote:

        > I think this concept is from Sweden, but when I look for foundation
        > plans from Sweden I have not found the specific plan for putting the
        > floor of the house 18 inches below ground.

        Sara;

        You describe something like the main floor level in my own home.

        The foundation is basically just a stem wall foundation whose
        footings extend to below the frost line (or as in the case of my
        home, sit on bedrock).

        In most situations, that would seldom be more than 4 to 6 feet below
        grade. In my case, bedrock was the pre-existing grade so finished
        grade was one that I created by bringing over 100 loads of fill.

        Inside of the stem wall whose top should extend at least 8 inches
        above finished grade, there should be drainage tile at the bottom
        with outlet drain(s) either to daylight or dry wells or sump pits --
        washed ,crushed stone fill and then insulation, moisture/soil gas
        barrier and then floor. The stem wall should of course, be insulated.

        That floor (or floors) can be at any height inside of the stem wall
        perimeter, depending upon how much stone fill you choose to place
        inside of the stem wall.

        Multiple floor levels are possible, simply by building what are
        essentially retaining walls within the perimeter stem wall, to
        contain/restrain the stone fill.

        The depth of the footings below grade can of course be reduced by
        installing perimeter "wing" insulation to raise the frost line (which
        sounds like what was done with the Swedish example you describe) not
        unlike the principle behind frost-protected shallow foundations
        (FPSF) [see link to downloadable guide & design manual in the LINKS
        section) but FPSF are, IMO not worth the extra cost & trouble.

        It's simpler/less costly, safer and less restrictive (ie for future
        additions) just to dig a bit deeper.


        === * ===
        Rob Tom
        Kanata, Ontario, Canada
        < A r c h i L o g i c at chaffY a h o o dot c a >
        manually winnow the chaff from my edress in your reply
      • sarakrohn92
        Thanks for getting back to me. I wonder if you have: Insulation under your floor levels, maybe above the stone fill? Radiant floor heat (hot water)? That is,
        Message 3 of 5 , Mar 2 5:52 PM
          Thanks for getting back to me.

          I wonder if you have:
          Insulation under your floor levels, maybe above the stone fill?
          Radiant floor heat (hot water)? That is, is the concrete the sub floor
          or are you walking on it?

          Are you warm, and has your fuel usage been what you had predicted it
          would be with this new floor?

          Did you forego a basement for design reasons or for economics; I had
          heard that 18 inches below ground has some sort of temperature
          stability so floors at that level are cooler in summer, warmer in
          winter. This could be an urban legend.

          I had read that FPSF are cheaper, but by the time one adds the wings
          in, maybe not.
          Thanks for your help


          --- In SB-r-us@yahoogroups.com, "RT" <archilogic@...> wrote:
          >
          > --- In SB-r-us@yahoogroups.com, "sarakrohn92" <sara@> wrote:
          >
          > > I think this concept is from Sweden, but when I look for foundation
          > > plans from Sweden I have not found the specific plan for putting the
          > > floor of the house 18 inches below ground.
          >
          > Sara;
          >
          > You describe something like the main floor level in my own home.
          >
          > The foundation is basically just a stem wall foundation whose
          > footings extend to below the frost line (or as in the case of my
          > home, sit on bedrock).
          >
          > In most situations, that would seldom be more than 4 to 6 feet below
          > grade. In my case, bedrock was the pre-existing grade so finished
          > grade was one that I created by bringing over 100 loads of fill.
          >
          > Inside of the stem wall whose top should extend at least 8 inches
          > above finished grade, there should be drainage tile at the bottom
          > with outlet drain(s) either to daylight or dry wells or sump pits --
          > washed ,crushed stone fill and then insulation, moisture/soil gas
          > barrier and then floor. The stem wall should of course, be insulated.
          >
          > That floor (or floors) can be at any height inside of the stem wall
          > perimeter, depending upon how much stone fill you choose to place
          > inside of the stem wall.
          >
          > Multiple floor levels are possible, simply by building what are
          > essentially retaining walls within the perimeter stem wall, to
          > contain/restrain the stone fill.
          >
          > The depth of the footings below grade can of course be reduced by
          > installing perimeter "wing" insulation to raise the frost line (which
          > sounds like what was done with the Swedish example you describe) not
          > unlike the principle behind frost-protected shallow foundations
          > (FPSF) [see link to downloadable guide & design manual in the LINKS
          > section) but FPSF are, IMO not worth the extra cost & trouble.
          >
          > It's simpler/less costly, safer and less restrictive (ie for future
          > additions) just to dig a bit deeper.
          >
          >
          > === * ===
          > Rob Tom
          > Kanata, Ontario, Canada
          > < A r c h i L o g i c at chaffY a h o o dot c a >
          > manually winnow the chaff from my edress in your reply
          >
        • RT
          ... Yes, of course. It would be foolish to have an earth-coupled slab in my 8750 HDD/yr climate, especially when there s only about 18 -24 of earth cover over
          Message 4 of 5 , Mar 3 11:09 PM
            --- In SB-r-us@yahoogroups.com, "sarakrohn92" <sara@...> wrote:

            >
            > I wonder if you have:
            > Insulation under your floor levels, maybe above the stone fill?

            Yes, of course. It would be foolish to have an earth-coupled slab in
            my 8750 HDD/yr climate, especially when there's only about 18"-24"
            of earth cover over the bedrock immediately surrounding the
            foundation perimeter.

            In some parts, the 6" of underslab foam insulation is on top of the
            crushed stone fill immediately under the slab.

            In other parts (ie where portions of the slab needed to be thickened,
            the foam was laid continuously and crushed stone placed on top ,
            mounded as requ'd to create the form for the thickened portions of
            the slab.

            In other parts, (ie under the slab of the attached sunspace where
            additional thermal mass was desired) the foam was placed under about
            2 ft of crushed stone.


            > Radiant floor heat (hot water)? That is, is the concrete the sub
            > floor or are you walking on it?

            There are no in-slab hydronics or any other embedded heating elements.
            It gets charged up by the sun. It's currently about 1:30 am and I am
            sitting here barefoot and comfortable, with no auxiliary heating of
            any kind. The last time that the woodstove was lit (the only
            auxiliary heating appliance that gets used) was some time last
            weekend.

            > Are you warm, and has your fuel usage been what you had predicted it
            > would be with this new floor?

            It's not a new floor. It's as old as the rest of the house -- over 20
            years old.

            Actually, the current fuel usage has been less that what was
            predicted at the design stage (ie over 2 decades ago).
            Winters have been getting milder.
            Last year, the most mild winter I've ever seen in this area, required
            a little more than 2.5 face cords of wood for the heating season.
            This year, it looks like it might take around 3 cords, since it has
            been snowier and colder.

            3 face cords (assuming 7.20E+06 Btus per cord) would put building
            performance at 1.07 Btu/HDD/yr/sf (space heating only).

            For the sake of comparison, one of my neighbours (whose house is
            about the same age and a little bit smaller) told me a couple of
            weeks ago that he used to burn 18 cords per season when he heated his
            home with wood only. (We were talking about heating Finnish saunas,
            he being a Finn who was literally born in a sauna. It was the warmest
            place his mother could find.)

            > Did you forego a basement for design reasons or for economics

            The height of the building from the top of the 1st level floor to the
            peak of the roof is just a little less than 30 ft.

            To place a full basement on top of the bedrock before building
            another 30 ft of house on top of it would have looked grossly out of
            place and then having to build a small hill of dirt just to conceal
            the basement and get up to the entry 9 ft up in the air seemed
            ridiculous (although that's what some people in this area did, and
            then in winter, they have to get SUVs so that they can make it up the
            hill of their laneways to get up to the house, which is even sillier
            IMO).

            The other option would have been to blast a hole into the bedrock to
            put in a basement which in reality, would have ended up being a
            spring-fed swimming pool... and that would have been bizarre. I have
            neighbours with full basements who keep two sump pumps running.

            > I had heard that 18 inches below ground has some sort of temperature
            > stability so floors at that level are cooler in summer, warmer in
            > winter

            Perhaps in some parts of the world that may be true but 18" below the
            surface here in Kanata would be frozen solid in winter.

            Stable earth temps are usually much deeper down, more like 5 feet or
            more where it might stay around 55 degF year-round.


            === * ===
            Rob Tom
            Kanata, Ontario, Canada
            < A r c h i L o g i c at chaffY a h o o dot c a >
            manually winnow the chaff from my edress in your reply

            >
          • sarakrohn92
            Thanks again. If I can t build new, I am considering buying a 50s ranch, with a traditional foundation, and was wondering how to go about making it more
            Message 5 of 5 , Mar 4 10:11 AM
              Thanks again. If I can't build new, I am considering buying a 50s
              ranch, with a traditional foundation, and was wondering how to go
              about making it more efficient. I think your tips will help me out.

              I have not found the links you mentioned in your first post to me:
              see link to downloadable guide & design manual in the LINKS
              section
              Can you be more specific as to how to find them?
              best wishes
              sk



              --- In SB-r-us@yahoogroups.com, "RT" <archilogic@...> wrote:
              >
              > --- In SB-r-us@yahoogroups.com, "sarakrohn92" <sara@> wrote:
              >
              > >
              > > I wonder if you have:
              > > Insulation under your floor levels, maybe above the stone fill?
              >
              > Yes, of course. It would be foolish to have an earth-coupled slab in
              > my 8750 HDD/yr climate, especially when there's only about 18"-24"
              > of earth cover over the bedrock immediately surrounding the
              > foundation perimeter.
              >
              > In some parts, the 6" of underslab foam insulation is on top of the
              > crushed stone fill immediately under the slab.
              >
              > In other parts (ie where portions of the slab needed to be thickened,
              > the foam was laid continuously and crushed stone placed on top ,
              > mounded as requ'd to create the form for the thickened portions of
              > the slab.
              >
              > In other parts, (ie under the slab of the attached sunspace where
              > additional thermal mass was desired) the foam was placed under about
              > 2 ft of crushed stone.
              >
              >
              > > Radiant floor heat (hot water)? That is, is the concrete the sub
              > > floor or are you walking on it?
              >
              > There are no in-slab hydronics or any other embedded heating elements.
              > It gets charged up by the sun. It's currently about 1:30 am and I am
              > sitting here barefoot and comfortable, with no auxiliary heating of
              > any kind. The last time that the woodstove was lit (the only
              > auxiliary heating appliance that gets used) was some time last
              > weekend.
              >
              > > Are you warm, and has your fuel usage been what you had predicted it
              > > would be with this new floor?
              >
              > It's not a new floor. It's as old as the rest of the house -- over 20
              > years old.
              >
              > Actually, the current fuel usage has been less that what was
              > predicted at the design stage (ie over 2 decades ago).
              > Winters have been getting milder.
              > Last year, the most mild winter I've ever seen in this area, required
              > a little more than 2.5 face cords of wood for the heating season.
              > This year, it looks like it might take around 3 cords, since it has
              > been snowier and colder.
              >
              > 3 face cords (assuming 7.20E+06 Btus per cord) would put building
              > performance at 1.07 Btu/HDD/yr/sf (space heating only).
              >
              > For the sake of comparison, one of my neighbours (whose house is
              > about the same age and a little bit smaller) told me a couple of
              > weeks ago that he used to burn 18 cords per season when he heated his
              > home with wood only. (We were talking about heating Finnish saunas,
              > he being a Finn who was literally born in a sauna. It was the warmest
              > place his mother could find.)
              >
              > > Did you forego a basement for design reasons or for economics
              >
              > The height of the building from the top of the 1st level floor to the
              > peak of the roof is just a little less than 30 ft.
              >
              > To place a full basement on top of the bedrock before building
              > another 30 ft of house on top of it would have looked grossly out of
              > place and then having to build a small hill of dirt just to conceal
              > the basement and get up to the entry 9 ft up in the air seemed
              > ridiculous (although that's what some people in this area did, and
              > then in winter, they have to get SUVs so that they can make it up the
              > hill of their laneways to get up to the house, which is even sillier
              > IMO).
              >
              > The other option would have been to blast a hole into the bedrock to
              > put in a basement which in reality, would have ended up being a
              > spring-fed swimming pool... and that would have been bizarre. I have
              > neighbours with full basements who keep two sump pumps running.
              >
              > > I had heard that 18 inches below ground has some sort of temperature
              > > stability so floors at that level are cooler in summer, warmer in
              > > winter
              >
              > Perhaps in some parts of the world that may be true but 18" below the
              > surface here in Kanata would be frozen solid in winter.
              >
              > Stable earth temps are usually much deeper down, more like 5 feet or
              > more where it might stay around 55 degF year-round.
              >
              >
              > === * ===
              > Rob Tom
              > Kanata, Ontario, Canada
              > < A r c h i L o g i c at chaffY a h o o dot c a >
              > manually winnow the chaff from my edress in your reply
              >
              > >
              >
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