The irregular verb spread is uninflected in its past-tense, perfect-tense, and past-participle forms. Spreaded is a not a dictionary-recognized word, but it appears occasionally in colloquial speech and informal writing.
Example
Though spreaded is rare in edited publications, it does appear from time to time—for example:
This pigment production plant is spreaded over 89 acres and includes a warehouse, R&D and application laboratory. [Business Standard]
The overall response to the incident inspired many kudos from Chief Ray, who spreaded credit around. [Sooke News Mirror]
Locals said the fire originated from electric short circuit at a house which soon spreaded to adjacent houses. [Financial Express]
For what it’s worth, spreaded appears most often in Indian, Pakistani, and Bangladeshi publications. We don’t know why this is.
These examples demonstrate the various uses of spread:
Crude oil spread its foul sheen over the Gulf. [Miami Herald]
Recently, especially near the coast, the most common tomato disease has been tomato late blight, which is spread by spores that are carried in the air, not the soil. [San Francisco Chronicle]
An army mutiny which erupted last week in the West African state of Burkina Faso has spread to a fourth city. [BBC]
