How to protect a piano from damp and humidity

Humidity is the single biggest threat to a piano in everyday use. More damage is done by moisture imbalance in homes and storage spaces than by moves, rough handling or age combined. Whether you are keeping a piano in its current location for decades or setting it up in a new home after a move, getting the humidity right is the most valuable thing you can do. For the move itself, you can get an instant fixed price at book.pianospeed.com.

Why humidity affects a piano so much

A piano contains a large amount of wood. The soundboard, bridges, pin block, keys, damper felts and hundreds of action parts all absorb and release moisture depending on the relative humidity in the room. Wood that swells and contracts repeatedly over years will crack, warp or split, and most of these failures are expensive to repair. Some change the sound of the instrument permanently.

The pin block is a block of laminated hardwood that holds the tuning pins in position. It must grip the pins tightly enough to hold pitch. If it dries out, the pins lose grip and the piano will not stay in tune. If it stays too wet for extended periods, the wood can swell to the point where pins are impossible to turn, and splitting becomes a risk when a technician eventually tries to move them. Either condition requires specialist repair, and the cost increases the longer it goes untreated.

The soundboard amplifies the vibrations of the strings. It is designed with a slight curve, called the crown, which is maintained in part by the wood being under tension. A soundboard that has dried out excessively will lose crown and buzz against the strings. In the worst cases it will crack along the grain. A soundboard that has been saturated may delaminate at the glue joints. Both are serious and neither is a quick fix.

The right humidity range

Piano technicians generally recommend keeping relative humidity between 45 and 60 per cent throughout the year. Within this range, wood movement is minimal and felt and leather parts remain supple. The most important thing is not hitting a precise number but keeping the level consistent. A piano that lives at a steady 50 per cent will fare far better than one that swings between 30 per cent in January and 75 per cent in a humid August.

A basic hygrometer placed near the piano costs a few pounds and is worth checking several times a year. Pay particular attention in October when central heating comes on in earnest and indoor humidity in British homes can drop sharply over just a few days.

Where you place the piano matters

Position is the first and cheapest line of defence. Certain locations in a room are consistently more stable than others, and a bad placement can undo everything else you do.

• Keep the piano away from radiators and underfloor heating vents, which create a dry zone directly around the instrument
• Avoid exterior walls in older or solid-walled properties where damp can wick through brick
• Do not position the piano directly under a skylight or next to a single-glazed window where condensation forms on cold nights
• Basements and lower ground floor rooms require closer monitoring: ground moisture raises humidity and fluctuations can be more severe than rooms above ground
• Conservatories and garden rooms are almost always unsuitable: temperature and humidity can swing by 30 points or more between a cold winter night and a hot summer afternoon

Using a humidifier or dehumidifier

If room humidity consistently falls outside the 45 to 60 per cent range, a room humidifier or dehumidifier is the right first step. In centrally heated London flats, indoor humidity can fall below 30 per cent in January. A cool-mist humidifier running through the heating season can make a significant difference without a large outlay.

For instruments that need closer control, in-piano humidifier systems such as the Dampp-Chaser Piano Life Saver are fitted inside the piano by a piano technician. These monitor and regulate humidity directly around the soundboard and pin block, which is more precise than trying to manage the humidity of an entire room. Many piano technicians recommend them for instruments in rooms with large seasonal variation, and for valuable or historic pianos.

Signs that humidity is already causing a problem

The following are all worth mentioning to your tuner or technician at the next visit. Caught early, most humidity-related problems can be corrected. Left for several years, some cannot.

• The piano goes out of tune rapidly between visits, or certain notes drift flat while the rest hold
• Keys stick down after being pressed, or feel heavy and slow to return
• You hear buzzes or rattles from inside the case that were not there before
• The case shows cracks at the joints or along flat surfaces
• The lid, fallboard or music desk binds when you open or close it

What happens to a piano during a move

Moving a piano from one building to another introduces a period of humidity adjustment. The instrument leaves an environment it has settled into, spends time in a van, and arrives in a new room with different humidity. This is normal and inevitable, and it is why we recommend waiting two to four weeks after delivery before booking the tuner. Tuning before the piano has acclimatised means the strings will move again as the wood settles and you will need a second appointment soon after.

If the piano is going into storage, climate-controlled storage is the only sensible choice. Ordinary self-storage units have highly variable humidity, and a piano left in one through a British summer and winter will almost certainly suffer. Our sister company PianoStorage.co.uk stores pianos in a dedicated climate-controlled environment.

Getting it right from the start

If you are planning to move a piano and want advice on how the new location compares, call us on 020 7164 0000. Piano moves start from £125 and you can get an instant fixed price at book.pianospeed.com. PianoSpeed is rated 4.9 out of 5 on Trustpilot from 77 reviews, all from real piano moves. PianoSpeed London Limited, 71-75 Shelton Street, Covent Garden, London WC2H 9JQ.