Why Guitar Bridges Lift and How We Fix Them

This Canadian made Seagull came into the shop with a problem we see on a lot of acoustic guitars: the bridge is lifting. It looks alarming, and left alone it only goes one way, but properly repaired it can be stable for the rest of the guitar’s life. Here is what is going on and how we fix it.

Why bridges lift in the first place

Most companies glue the bridge straight onto the finish rather than onto bare wood, and finish to wood is inherently not a great bond. Give it years of string tension and, typically, the bridge starts to lift. A few things speed it up: medium gauge strings or heavier strings than the guitar was built for, and drying out, which leaning against a wall in a Calgary winter does nicely.

The fix is wood on wood

The repair that lasts is to remove the finish from the soundboard and from the underside of the bridge, so when it is glued back it becomes a wood on wood bond. Done that way, it stabilises the joint for life rather than buying a few more years.

This one needed more than glue

When this Seagull came in, the top had a pretty significant hump behind the bridge, what is called a bellied top. With the soundboard distorted like that, we could not simply glue the bridge back on, because it would not seat properly against the curve. So first we heated and moisturised the wood, then levelled it and clamped it flat. Only once the top was back where it should be could the bridge go on properly.

Keeping it from coming back

To stop the belly returning, we are recommending a product called a Bridge Doctor. It fits through a small hole in the bridge, with a system inside the body that pulls the belly down and holds the soundboard’s shape. Tone is not affected, and it is a pretty amazing bit of kit. It prevents the bellying from coming back, stops the bridge wanting to lift again, and stabilises the guitar for many years.

Caught early, it is a smaller job

A lifting bridge you can slide a piece of paper under is a much simpler repair than one that has been pulling the top out of shape for years. If you can see a gap opening behind your bridge, worth having it looked at sooner rather than later. It is exactly the sort of thing we check during a setup assessment, and our before and after page has examples of structural repairs like this one.

Common questions

How do I know if my bridge is lifting?

Look at the back edge of the bridge. If you can see a gap, or slide a piece of paper underneath it, it is lifting. Rising action and a visible hump in the top behind the bridge are the other tells.

Can I just glue it down myself?

Squeezing glue into the gap does not work, because the bond is still finish to wood and the string tension that lifted it the first time is still there. The lasting repair means removing the bridge, cleaning both surfaces back to wood and regluing under proper clamps.

Will heavier strings damage my acoustic?

Heavier than the guitar was built for, over enough time, they can contribute to a lifting bridge and a bellied top. If you like heavy strings, it is worth having the guitar checked over now and then so anything starting gets caught early.

Spotted a gap behind your bridge?

Bring your instrument into the shop during opening hours, no appointment needed. Assessments are free and we can usually do them while you’re here, so you leave knowing exactly what it needs. Hours and directions are on the contact page.

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