This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 宲 is uncertain. It visually combines 宀 (roof) and 呆, but the original semantic or phonetic role of these components is unclear.
With no clear meaning, picture a roof 宀 over a wooden post 呆 as a mysterious storage shed where things are tucked away.
For ホウ, imagine a storage shed with a sign reading 'HOUse' where things are stowed: HO -> ホウ.