Here is a question that I got recently in the email:

My first floor ceiling now has a horizontal opening say .8 metres by .8
metres with a hatch bordered by a frame. When the hatch is opened you can
grab the loft ladder and access the loft. Does the hatch need a mezuzzah.
Can you place a mezuzah on the horizontal.

Here’s my answer:

Dear Sir,

Any door that is horizontal is exempt from a Mezuzah.  In fact I have the same kind of hatch in my home here in Israel.

Be well,

Aaron Shaffier
MezuzahStore.com