Twin wall flue system design, wall thickness

Wall thickness and twin wall flue systems We need to know the thickness of the wall through which the twin wall flue will run. This is the distance from the inside surface of the wall to the outside surface.

How to measure the wall thickness through a window or door reveal You can easily measure this distance by opening a window or door and measuring the thickness of the wall through the window or door. If you have an old building try and measure the thickness of the wall as near to where the flue will penetrate the wall as possible (the thickness of walls in old buildings can vary a lot).