Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Running up and down stairs to reduce creaking.

  1. Oct 30, 2005 #1
    Tell me if this theory of mine makes sense.

    The stairs in my house creak. Creaking is caused when you step on stairs.

    It makes sense to me that it should be quieter to run up and down my stairs, that they should creak less.

    Here is the reason.

    When you walk up stairs usually, you push all your weight up with one foot, and then rest all your weight on another step. All your weight gets pushed down on the stair, which in repsonse, creaks. If you run up, and get a good push off of the ground, you start out with upward inertia. It takes less of a push-off from any individual step to get to the next one, since you've already got upwards inertia.

    With running down the stairs, again, you're not fully coming to a rest on any stair. If I'm only touching a stair long enough to kind of guide myself down, it seems that I'm not putting all the force my body has to offer onto that stair, and again, I'd push down on it less, and it should make less noise.

    I think this works. My mom doesn't. I think it's just cause she associates running with noise in her head, and even though walking slowly would cause lots of slow creaks, the rapid-fire minute creeks combined with seeing me go up the stairs quick puts her in an unusual frame of mind, like running inherently causes disruptions.

    In theory at least, is my idea correct?

  2. jcsd
  3. Oct 30, 2005 #2
    nope there still gonna creek, why dont u just go run up your stairs to test your idea.
    god damnit i hate creaky stairs to, you cant escape them
  4. Oct 30, 2005 #3


    User Avatar
    Science Advisor
    Homework Helper

    Wait until Tuesday! Creaking stairs are great for Halloween!

    After that, recognize that by running you have to press down harder on the stairs (essentially, you do come to rest on each step and need to apply a greater force to get back up to speed!). This would lead to louder creaking. However, over time, the repeated creaking may smooth the surfaces that are rubbing together thereby reducing the amount of creaking.

    Also, running up (and down) stairs does present its own perils and I'm sure mom has that aspect in mind! :)
  5. Oct 30, 2005 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    In an extreme case, creaking steps could be replaced by crashing steps.

    Consider a set of steps which you know to be rotten and weak, do you run up them or step ever so carefully?

    Another consideration.
    Perhaps by exerting a greater force on the step you will change the frequency of the creak, making it less audible. Just a thought.
  6. Oct 30, 2005 #5
    Ninja's might have something to say about this.
    A descent down a creaky staircase can be virtually unnoticible if the following conditions are met:
    The Ninja launches forward from the top of the stairs, in a slight upward arc.
    The "touching" of the stairs with the feet in descent are merely used to stabilize the parabolic descent, and very little impact force is required during this. The Ninja thus descends to the bottom with little sound.

    Going up a creaky staircase is another matter, and very difficult.

    Again, the Ninja must launch forwards and upwards, as much as he can, but the secret is how his body translates during this. He draws his feet upwards towards his body during the "push-touching of the stairs" while ascending. The use of the hands and fingers during this are also important, as the weight of the Ninja becomes distributed upon multiple stairs.
  7. Oct 30, 2005 #6
    just get a damn screw gun and put like a box of screws there them all
  8. Oct 30, 2005 #7
    It's not nice to fool Mother NINJA !!

    OK, maybe your not old enough to get that joke.
  9. Oct 31, 2005 #8


    User Avatar
    Science Advisor
    Gold Member

    Was thinking of something similar, the frequency response being tied to the 'dynamic stiffness' of the structure, moving the creaaking to higher frequencies. Of course this implies that you could attempt a permanent solution, overloading the steps by running up an down with some extra weights on :rofl: .
  10. Oct 31, 2005 #9


    User Avatar
    Gold Member

    Just slide down the bannister instead. Then you won't make any noise at all until you sack yourself on the newel post.

    I'm under the impression that the squeak in floors and stairs is due to boards sliding up and down on the nails, not rubbing on each other. Lubricating the offending parts with a little soap or something can cure it.
  11. Oct 31, 2005 #10


    User Avatar
    Science Advisor
    Homework Helper

    It makes sense to me. What you're saying is that by running up the stairs, the total amount of work the stairs have to do no you is slightly reduced. This seems counterintuitive in that the total amount of work done on you is evidently gravity X height X weight, but if the response of the stairs is slow enough, they will move less when your weight is on them for a shorter time.

    And of course if you begin your climb with enough velocity, you (superman) can jump to the top of the flight while touching none of the stairs at all.

    This makes sense to me too. The total amount of "creak work" that you do on a step is going to equal the distance you move it multiplied by the force. Now your force is always going to equal, more or less, your body weight, but if the stair reacts slowly enough, or if you apply your weight to it for a short enough time, then the stair should have no creak work done on it.

    This is more clear if you take it to the limit. Suppose you step on each stair for an infinitesimal length of time. How much will the stair move? Clearly not at all.

    Another way of looking at this is to try to get an estimate of how long it takes a stair step to reach equilibrium under your weight. The only time duration you have to estimate this with is either the duration of the squeak, or the period of vibration of the squeak. If it's the duration of the squeak, then your method should work.

  12. Oct 31, 2005 #11

    Hans de Vries

    User Avatar
    Science Advisor
    Gold Member


    You can reduce the pressure on the stair steps threefold by standing on
    both your hands and feet while moving only one limb at a time.

    When you've mastered that then you can go for a fourfold reduction by also
    using your head as a fifth limb.

    I don't now what your mom will say though :rofl:

    Regards, Hans
    Last edited: Oct 31, 2005
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook