Hi,
I have a deck fascia clad in Hardie board (I believe). Beneath the Hardie are various lengths of timber, some of which has rotted, that is then attached to timber beams on the end grain (see attached photos). I recently noticed water has been seeping in and the fascia has come loose. I want to repair this properly and seal the fascia from the tiles above, which seems to be missing.
What would be the best materials and method to fix? I want something that won’t rot eventually, so are there any other alternatives (at least for the timber packing behind the Hardie board).



