Grand pianos and baby grand pianos are often beautiful pieces of craftsmanship and produce excellent sound while providing a unique decor. What they don't do, however, is store well or move from place to place easily. If you have the choice of whether or not to move a grand piano or store it it is best to leave it alone. If you must store a grand piano then it is better to find someone willing to take care of it and play it than to leave it in prolonged or unheated storage.
Rent a self-storage cubicle. The cubicle should be at least 8'x8'x6' or 5'x8'x10' to accommodate a grand piano.
Check if the storage facility is heated. Low heat is fine for the piano but too much heat is actually worse for a piano than cold.
Move the piano onto a skid and crate to move. Remove all piano legs. Move the piano in covered truck.
Prevent moisture from getting into the piano wood. Place chewing tobacco in a nylon hanging inside the piano. Dampness will cause more damage than the cold.
Store the piano on its feet. Storing the piano on its side long-term may cause actions to warp and the hammers to come out of alignment. Have a piano tuner remove the actions if the grand piano is to be stored on its side long-term.
Return the piano to its correct position after storage. Have a professional piano turner assess the piano for any damage incurred during storage and do a full tune of the piano.
Try to keep your grand piano in a warm but not overly humid environment as the wood runs a greater risk of warping and damage.
Always check with your movers if they have experience moving pianos. Pianos will often need to be put onto a skid and crated with their legs removed. This requires very careful work.
Relocating a piano will always run the risk of damaging fragile internal components. Move grand pianos sparingly and keep them in storage as little often as possible.