Tongue-and-groove ceiling materials are manufactured from wood and come in a wide variety of natural wood grain colors. The system, unlike drywall, is easy enough for one person to install and will cover damaged or imperfect surfaces. On the downside, they have a somewhat limited application and are best suited for rustic-style spaces than most other decorating styles. They aren’t as resistant to sound transfer as drywall, and they are difficult to paint.
The most common source of creaking and other noise is footsteps or movement from upstairs. Drywall is significantly better at eliminating these sounds than tongue and groove, but some noise dampening padding will also do the trick. This material, available from most hardware or home improvement stores, is applied under the tongue and groove to add some insulation between the surfaces. It will aid in reducing the amount of noise from upper floors that is heard downstairs.
Squeaks are sometimes the result of the wood slats rubbing together. These sounds often become worse when weather is humid, as the additional moisture causes some boards to swell. Though it is not a structural concern and won’t normally damage the tongue-and-groove material, the sounds are often annoying to listen to. The repair is as simple as locating the source of the squeak and applying a lubricant. There are both liquid and powdered products -- both are appropriate for treating a squeaking tongue-and-groove ceiling.
A shim is a thin, tapered strip of wood and is an ideal way to treat squeaking and cracking caused by the ceiling material moving up and down. Use a hammer to insert a shim into the source of the noise to eliminate movement. There are both standard wood shims and recycled plastic products, both of which are durable enough for the job. Installing a screw between the noisy slats will serve a similar purpose as a shim. Place the screw at an angle and apply some construction adhesive into the seam.