What makes a door internal/external?

[600rob]

Looking for a hardwood door as a replacment for a garge pedestrian access door and im wondering what classifies a door as internal or external.

Something to do with the construction?

Initially i thought any hardwood door should be good for external use but maybe not?

 

[JohnD]

External doors are generally 44mm thick, and internal doors 35mm

Internal doors are generally very flimsy, and may contain materials such as chipboard hidden under the veneer.

Lift a few up and you will notice the difference.

 

[Deleted member 174758]

External doors are generally 44mm thick, and internal doors 35mm

In modern apartment housing it's becoming more common to find 51mm for externals (1 hour fire rated in, say, a block of flats with a communal entrance) and 44mm solid core internals. Whilst externals used to be solid wood or veneer-faced and edge lipped laminboard (strips of hardwood glued together) other core materials for exterior wooden doors are appearing such as MR chipboard and Accoya MDF

I wouldn't call a 44mm internal 30 minute fire rated door flimsy, either - try kicking your way through one and you'll see what I mean!

I agree that weight is a really good indicator of sound proofing properties