What is acoustic guitar “bellying”?

“Bellying” refers to bowing of the soundboard of an acoustic guitar. The constant tension applied by the strings causes the bridge to rotate forward towards the neck; resulting in the warping of the top (especially behind the bridge), a slight drop at the sound hole and a raised action.

How to tell that if your guitar has it?

A simple test is to take a ruler and lay it flat directly behind the bridge. If the top has bowed, gaps should be visible between the side of the ruler and top of the guitar. It’s difficult to know when bellying would be considered severe but a general rule would consider 2-3mm upwards as a bowed top.

Another simple test would be to lay the ruler over the top of the bridge pointing down the neck. If the bridge has rotated forward, the ruler will point downwards towards the sound hole.

What can I do to fix it?

As is the case with most guitar related problems, there are many ways to fix them. However, with a bellied guitar, most “repairs” are merely temporary. A bridge or neck reset, filing of the bridge saddle, etc; they will only work for so long.

A highly recommended option is the JLD Bridge Doctor, a bridge truss system which will permanently eliminate the bellying from your acoustic guitar. You can see how it works HERE