There are no effective methods to deter mud daubers from building their nests in a particular area. Removal of existing nests in the evening or at night when the insects are less active is probably among one of the better options. They are generally non-aggressive wasps that are very beneficial around gardens. They may provision their nests with caterpillars or spiders, and one of our common ones in this area uses spiders. Some species reuse old nests after repairing them. Tactics that reduce the number of spiders found in the shed may reduce the likelihood they build nests in your shed. Additionally, caulking and sealing entrance-paths into your shed may help. Physical removal of nests on the outside is your best option and should occur in the evening.