Tudor boards slight rot at bottom, splice section, what resin/filler?

[Mr Chibs]

I need to repair some Tudor boards, as there is a small amount of rot at the bottom of a couple of boards.

I would like to splice in a new section... probably around 100mm tall.

Is there some type of filler or resin I could use to glue the new sections in? something waterproof and flexible.
I would normally use expanding PU glue, just wondered if there is something more suitable.

I don't think the budget will stretch to Mock Tudor boards, before someone mentions it.

TIA

 

[^woody^]

Wouldn't you want to do a mock repair that mocks a repair to a Tudor beam , rather than a fake repair that fakes a repair to a bit of 6x1?

 

[Mr Chibs]

Was just after some suggestions on filler/glue.

The faux beams, look like 200 x 40 rough sawn.

 

[^woody^]

You got a bonus answer then