The build

Back to playing with the MVHR today.

Bob finished drilling the holes through the house. This is how thick the external walls are.   That’s the external cladding you can see.

Then Bob went through from the outside   . Then he put the vent over the hole so nothing thinks that a good place to roost  . Hope to finish it tomorrow morning.

Totally understand about roosting critters. We put an extractor fan in the 2nd floor IOW flat, only to find next spring sparrows had nested, even though there was an outer grill. Only way to get rid was to wait till they fledged and put bundled wire mesh in place in the cavity. It didn't stop them so had to get a man with a scaffold tower to further protect the outer face. They made an awful racket!