Although not common, if you see these issues on your timber- hopefully we can explain why it happens.
Peeling is a visual issue, where the surface varnish is peeling off, exposing the unfinished timber below. Exposing it to dust, dirt, and moisture.
Some common causes:
If the surface finished with a solvent/ oil/ water based polyurethane. Normally, in order to create a solid bond between layers, each surface needs to be scuffed.
If not, the above layer will not adhere and start to peel off a couple of months after completion.
If the existing timber is prone to oil- such as brush box, spotted gum, cypress, tallowwood, the surface needs to be primed before applying the top coat. Otherwise it will not adhere and peel off.
Minute timber movement can delaminate the surface.
If the wrong mix of water/ oil/ solvent based finish is used and not completely left to dry. It can peel.
If the timber has been finished previously with an oil, it will needs to be sanded back to raw timber and all oil residue to be cleaned before a polyurethane finish can be applied.