Adding a Letterbox or Letter Plate Through the Wall Damp can be a major issue in the home. Find answers to questions or post your own here.

[Jono14]

Hi I am having a new front door fitted but the design of the door does not lend itself to having a letter plate in it . The options are fix a letter box on the wall outside or my preferred option is put a letter plate on the wall with a sleeve going through a cavity wall . That way my post will be inside .
I am a little concerned with cold bridging ( cold air meeting warm air and forming condensation ) has anybody had any experience in this area ? I was going the build a box on the inside and insulate it .
Many thanks

[welsh brickie]

use plastic to form the sleeve, and expanding foam to fill in around it.

[Jono14]

Was thinking of using ply to form the sleeve ?