Why British carriers used stacked enclosed hangars

Why did British aircraft carriers use stacked hangars instead of one long open hangar?

The enclosed stacked arrangement protected aircraft and workshops from North Sea conditions and let heavy maintenance continue without blocking the main hangar.

British carrier hangars remained long, but unlike open-ended arrangements they were integrated inside the ship. The enclosure protected aircraft from harsh North Sea weather and reduced the risk of equipment being lost overboard. A lower hangar could also house workshops and aircraft undergoing heavy maintenance. That separation kept major repair work from interrupting movement through the principal operating hangar, making the stacked arrangement an aviation-support system rather than a simple way to store more aircraft.