Even when a structural piece of equipment is mounted into the wooden framework of a house, there can be settling and shifting over time that moves the timbers and supports. A house will "settle" into a certain position based on the load bearing over decades. Any new weight or change can shift that balance and if something moves enough, plaster or wall board will crack. When we bought this house, it was on the third tier of roofing tiles. When the time came to put on a new roof, the three old layers were torn off–representing a good several hundred–maybe a thousand pounds of tiles. We had to pay carpenters an extra few hundred dollars to replace some cracked roof timbers before the new roof went on.

I could never stand up in the center of the attic. Then, a few months later, hauling down the Christmas tree, I noticed I was standing up straight! Taking the tons of tile off the top of the house had unbowed the timbers and the house was an inch or two taller!

It’s likely you did nothing wrong at all. Old gypsum and plaster is notoriously brittle. It’s likely the normal use of your pole caused a tiny bit of subsidence. When you had the pole party, it was the straw that broke the camel’s back!

One day before we signed our closing documents (13 years ago), a father and son robbery team knocked off the liquor store on the corner with a sawed off shot-gun and came roaring down the street, missing the turn, and hitting our "soon to be front porch." After tense discussions with the insurance company to repair $12, 000 damage to the house, we closed anyway–and haven’t regretted it!

But if you take a marble and put it on any part of hardwood floor you can find, it will always roll to the southwest. Our house is just ever so slightly tilted, now–like an episode of Batman!

Joel

PS: The robbers? Yes, they got caught–they were passed out in the car when the cops arrived. We don’t live in a dangerous neighborhood–really–but I’m sorry to say the house was hit again (!) five years later! This time, simple drunkeness was the cause!