as doors and drawers become tight with high humidity and loose in
dry air, the keys of your piano may stick down when struck in times
of high humidity. When the environment surrounding your piano is
dry the keys may seem to rattle when played.
you play your piano, you will notice how responsive the keys are
to your touch. The way the keys cause the hammers to strike the
piano strings is part of thousands of interconnected wooden parts
called the piano action. With high moisture levels in the piano
action, the action is sluggish, and the keys seem non-responsive
to your touch.
Bridge and Soundboard Damage
The soundboard is the single largest
piece of wood in your piano. It actually vibrates to amplify the
sound produced by the strings. The bridges of your piano are joined
to the soundboard and support the strings.
the soundboard absorbs moisture from the air surrounding the piano,
it swells, producing an upward bulge. Through the bridge, this puts
additional tension on the strings. Now, the pitch is too high in
the lower mid-range and treble section.
the soundboard shrinks and flattens, the tension of strings over
the bridge becomes inadequate. The pitch of the mid-range and treble
section is now flat.
time, constant changes in humidity levels, with the corresponding
shrinking and swelling of the soundboard, will damage the integrity
of the soundboard. You will see this damage in the form of a crack
in the soundboard.
strings of your piano are held tight by the pins in the pinblock.
As the pinblock absorbs moisture in periods of high humidity, it
swells, crushing the wood fibers against the pin.
dry periods, the wood shrinks away from the pin, loosening it and
causing the string to sag. When this cycle is reapted time after
time, the wood fiber surrounding the pin are destroyed and lose
this picture, this pinblock (without pins) was removed from a piano
during restoration. With continuous swelling and shrinking, the
wood could no longer provide the snug fit required to hold pins
strings of your piano are responsible for producing the musical
sounds. With exposure to high humidity levels over long periods,
strings become rusted and corroded.
the junction where rusted strings wrap around rusted pins, rusted
corrosion forms a hardened bond between the two. Then, during a
tuning, when your piano technician turns the pins to stretch the
strings, the inflexible rusted string snap at this joint.