Warped Wooden Garage Door

ThisIsWeird

@ThisIsWeird following more research we have decided to install a turnbuckle and are using this to provide tension to pull the door in over time. This will hopefully keep it in place long term. Thank you for your suggestions. 

Curious as to how you've set that up, SP? But, if it pulls the warp back either straight or ideally beyond straight, then fingers crossed.

Any chance of a photo, please?

Alternatively, if you wish to go the Eldi_Dos route, then rubber door wedges are both cheap and should prevent any damage. In fact, every time you close the door, you could just kick one under whilst pushing the warp back as much as possible. Any retained movement should end up a wee gain!