The inherently unstable nature of domain walls makes their detection in laboratory experiments extremely challenging. We propose a method to stabilize domain walls inside a cavity. The method requires domain walls coupled to matter, a condition that is fulfilled by the symmetron model. We suggest two ways in which the walls could be detected once stabilized: studying the trajectories of ultracold neutrons either via the deflection angle of a neutron beam induced by the attraction towards the wall or through the time difference of these particles passing through the wall. We give realistic estimates for these effects and expect that they should be detectable experimentally.