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Wood and brick homes?

  1. Jan 5, 2007 #1
    From looking at my book, brick has a resistance value of 0.43 and wood has a resistance value of 5.0. So wood should be a much better insulator. However homes are usually built with brick. Good homes have a double layer but air only has a resistance value of 1.0

    Brick homes are considered better and more common. Why build homes with brick if they are poor insulators? Is it because they are stronger than wood and lasts longer. This factor is more important than insulation when considering materials for homes?

    Or would it be because wood homes only have a thin layer whereas bricks are thicker. So this would make bricks a bit better insulators espeically if doubled layer brick homes.
     
  2. jcsd
  3. Jan 5, 2007 #2

    cristo

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    When building a house, I'm not sure whether one would choose the material by picking the one with best insulation. For example, wood has many disadvantages compared with brick, in that it is more flammable, less sturdy, less waterproof.. to name but a few.

    It is far better to build the house from the most suitable material fitting most criteria, and to then solve the problem of insulation (i,e, stuffing insulative material in the wall cavities.)
     
  4. Jan 5, 2007 #3
    One optimal design is to use lots of exposed brick and stone (high thermal mass) for the interior, but sheath the exterior with wooden weatherboards or other insulator. Combined with good window placement and sizing, in many climates this can remove the need for active heating/cooling.
     
  5. Jan 5, 2007 #4
    I think thermal mass is a big factor. From experience the old parts of my house which have solid stone walls 2 foot thick maintain a very constant temperature year round providing the house is occupied.
    If we go on holiday and the heating is off then it takes nearly a week to get warmth back into the walls.
    Recent studies on converted Tudor buildings have shown that the Wooden frame and Wattle and Daub walls have better energy efficiency than modern brick but as the building moves and settles they become very drafty due to a lot of gaps and cracks.
    Studies into Straw Houses (By Three Little Pigs Construction) have shown that by building in standard bales pegged with steel pins and then rendered both sides, you can build a house incredibly quickly and cheaply, but the cost of fire proofing the staw to meet current regulations is prohibitive. Stupid thing is that once rendered and air tight the straw is just as fire proof a cavity wall insulation that doesn't need treating.
     
  6. Jan 5, 2007 #5
    For a long time now, the brick used for homes is largely decorative rather than structural and is just a single brick thickness offset slightly from the actual wood frame and sheathing of the house. The brick isn't really meant for insulating. There are easier and better ways to insulate a house with other materials.
     
  7. Jan 5, 2007 #6
    Brick just looks nicer. Either way, it doesn't really matter all that much, since the actual insulation will limit heat transfer far more than wood or brick can.
     
  8. Jan 5, 2007 #7
    What is the actual insulation? You mean using special materials and designs inside the wall.
     
  9. Jan 5, 2007 #8

    rbj

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    not anywhere i had lived. (unless you count large multiunit dwellings like housing complexes and high-rise apts.) for regular, single family homes or even duplexes, wood construction is far more common because it is less expesive.

    i wish either of the homes i own (in VT and NJ) were brick.
     
  10. Jan 5, 2007 #9

    russ_watters

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    Brick is usually used these days because it looks nice, not for structural reasons. When it is used for structural reasons, it makes for very sturdy buildings.

    Insulation value is utterly irrelevant to whether you use brick or wood because either way there are insulation standards that by law have to be met - and it isn't like it is a big deal to add insulation. So today, a brick house and a wood house will have exactly the same insulation value. Walls are generally required to be insulated to about R-19. So assuming your numbers are in R value per inch of thickness, your walls would need to be four inches thick of solid wood.

    So as that would imply, the numbers you quoted don't tell even half the story - a wood frame building doesn't use wood for insulation and a brick building doesn't depend on the brick for insulation. Buildings use insulation for insulation.
     
    Last edited: Jan 5, 2007
  11. Jan 6, 2007 #10

    Danger

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    I'm glad that this subject came up. As I mentioned to someone here in an e-mail (or PM; I forget), we had to send my mother to the hospital about a month ago, and she's never going home (not terminal; she's been moved to a nursing home). W and I are going to move into the house, once we can make it habitable. My grandfather built it in 1911. It was originally a frame building, then someone plastered over the outside, and a couple of years later it was covered with brick. The thing is probably earthquake-proof (as if we have significant earthquakes in southern Alberta :rolleyes: ), but the insulation value is near zero. It was nice to see some relevant posting.
     
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