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How Does Humidity Affect My Piano?

Table of contents for Pianos & Humidity

  1. How Does Humidity Affect My Piano?
  2. How Do I Measure Piano Humidity Swings?
  3. Where Should I Locate My Piano?
  4. How Long Should I Wait After Moving?

Humidity Swings And Piano Parts

Everything in a piano is either made of wood or depends on wooden parts to function. Wet, humid conditions, swell and warps wooden parts and dry, parched conditions shrinks and cracks wooden piano parts. High humidity badly affects a piano and low humidity badly affects a piano, and even worse is this swinging back and forth, which is what we have in Kansas City ~ hot, humid summers and cold, dry winters.

Dryness causes wood to crack, which is the most serious damage, and many times those cracks would never develop, without first going through a period of damp, humid conditions.

Soundboard Pressure Ridges

For example, let’s take the soundboard:

The soundboard already has a vast amount of pressure exerted on it; and wet, humid conditions cause it to swell, pushing the wood grain with enormous force the soundboard sometimes develops a “pressure ridge”. To view these pressure ridges on grand pianos, lower your eyesight to just above the level with the soundboard ~ to the point where the light glares off the soundboard. Locate the “pressure ridge” and run your finger across the ridge and feel it under your finger.

At this point, the pressure ridge is not considered a crack and a piano manufacturer will not guarantee a “pressure ridge”, yet if the piano goes through a period of dryness, this is where the crack will most likely develop. “Pressure ridges” can be seen on many pianos still sitting on the dealer’s showroom floor. This is one more, of the many reasons why buying a piano WITHOUT first scheduling a trusted professional piano tuner to inspect the piano before signing a purchase contract, is never, never, never a good idea.

Soundboard cracks usually do not cause much of a problem with the tone and overall sound of your piano unless the soundboard ribs loosen and begin to buzz and rattle. Unless, there is a rattle or buzz the soundboard will still perform, but the crack does devalue your piano.

Humidity Swings And The Piano Pinblock

Piano Pinblock

Piano Pinblock

A more serious problem that may develop as a result of “humidity swings” is pin-block damage. The pinblock is what holds the tuning pins. The quality and condition of the pinblock determines the tightness of tuning pins and is one of the most significant factors in tuning stability. For many manufacturers, including Steinway, the minimum specification allowed for tuning pin tightness, to pass inspection and exit the factory is only 50 inch pounds. While technicians, like myself, would like all new pianos to measure 75 to 85 inch pounds many pianos leave the factory with only the minimum specification

What This Means For The Piano Owner?

A piano is still tunable at 50 to 60 inch pounds, but once the pinblock loosens to the extent the tightness of the tuning pins only measures 25 to 30 inch pounds, that piano is no longer considered a tunable piano. After a piano has gone through a few seasonal changes, it is not uncommon for the pinblock to loosen five to ten inch pounds in the first five years of service. To avoid getting stuck with one of those 50 inch pound pianos, never, never, never buy a piano without a professional piano tuner appraising the quality of the piano before purchase.

Piano Pinblock

Piano Pinblock

Dry Piano Pinblock Conditions

Dry Piano Pinblock Conditions

Moist Piano Pinblock Conditions

Moist Piano Pinblock Conditions

Rusted Piano Tuning Pins and Piano Strings

Rusted Piano Tuning Pins and Piano Strings

Piano Pinblock Damage (Tuning Pins Removed)

Piano Pinblock Damage (Tuning Pins Removed)

Rusted Piano String Damage

Rusted Piano String Damage

Piano Bridge ~ Dry Conditions

Piano Bridge ~ Dry Conditions

Piano Bridge ~ Moist Conditions

Piano Bridge ~ Moist Conditions

Cracked Piano Soundboard

Cracked Piano Soundboard

Sluggish Piano Action Resulting From High Humidity

Sluggish Piano Action Resulting From High Humidity

Sticking Piano Keys Caused From Too Much Moisture ~ Humidity

Sticking Piano Keys Caused From Too Much Moisture ~ Humidity

Note: Piano manufacturers design soundboards to have a crown. The image for “Dry Conditions” shows a flat soundboard which is not accurate. In dry conditions, I am sure the soundboard flattens more than it should but not entirely flat.

9 Responses to How Does Humidity Affect My Piano?

  • Hi Chuck!
    I read your article on the myth of waiting months before tuning a piano post-move. We just moved an early 1900’s Sherman Clay, Aldrich upright, piano from three miles away into our home in Washington state. I had been told by some piano movers that after a bumpy move we should not play the piano for several months -to let it settle. They said that doing so could permanently damage it. We did not have professional piano movers help us this time around, we moved it ourselves with a UHaul trailer and some creativity. What is your advice for us pertaining to having it tuned and when it is ok to play?

    Thank you so much for your time!

    • Tune the piano as soon as possible; but if you have an “old” upright, it is rare to find one that is still able to be tuned. You will have to have a professional piano tuner look at the piano to know for sure if it can be tuned or not. As far as “playing” the piano after a move, I have never heard of not playing a piano after a move. It is impossible for “normal playing” to harm a piano no matter if it has been moved or not…

  • I have a 4 year old Yamaha Clavinova CVP501. I am very disappointed to record that I am having problems with it. The screen won’t light up. I did phone 1 repairer who said a part will have been damaged due to humidity problems. I bought this digital piano mainly as I didn’t want the extremes of temperature to affect it. If it can’t be fixed (very expensive for $4500.00) – I will be very upset.

    • I am so sorry to hear about your problems; unfortunately I am not going to be any help. Yamaha Clavinovas are electronic interments which require a completely different skill set from that of a piano tuner.

      • I have to advise that after a couple of months, the Piano started working again. The humidity is very bad here in summer. I put one of those humidity suckers inside the Piano and after a while, much to my delight, the Piano started working again.

  • We’ve been hearing a mysterious popping noise in our family room. It’s been going on for several months. I believe it’s coming from my wife’s piano.

    The piano is against an inside wall but only a couple of feet from an outside wall and 5 feet from the door. The temp stays between 70-76 year round in our home.

    Any thoughts on what might be causing this popping?

    • In 28 years of servicing pianos, there is only thing I have found to cause the sounds you are describing; mice are probably running around inside your piano. Mouse damage is an infrequent cause of piano damage.

  • You are the only one I have seen who notes that the pin block holes can get sloppy if dried out. I serviced a piano in a church (an old Steck) where the pins were nearly unserviceable. As a heroic measure, I recommended – and installed – a Dampp-Chaser system with the undercover.

    After a few weeks, I came back to do the followup tuning. I was shocked that the pins had snugged up enough to hold its tune. They were not tight, of course, but they were workable; and the progressing damage was arrested. Good news for the customer.

    • Thanks for your support and comment Ron,

      I hate to disagree, but the pins tightening up after a couple weeks would not be as a result of installing a Dampp-Chaser system. They do NOTHING for the pin-block. I suspect, had you NOT installed the system, and came back in a few weeks for some other reason you would have discovered the same amount of tightening. The tightening was a result of the weather not installing a Dampp-Chaser system. If you had used a hygrometer to measure the humidity, you would have discovered the humidity changed in the entire room. I am sure the Dampp-Chaser company would tell you their little systems are not effective enough to change the environment in the entire room. They only work under the soundboard and have NO affect on the pinblock.

      The next article in this series, “How Do I Measure Piano Humidity Swings?” I discuss both my praise and my critiques of Piano Life Savor Systems (Dampp-Chaser Systems).

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