Damp Wooden Beams in Garage

[Cellophaneskies]

hi all,

House ownership is frustrating!

My garage has a tilted roof with tiles. Inside, you can see the wooden supports running from brackets in the house down to the edge wall of the garage. One of these af the very end is getting damp and going soft.

On the other side of this beam is the exterior. Here we have wooden planks running horizontally and overlappingg from top to bottom. I imagine this is water is getting in as they don't sit flush and they're visible behind the wooden supports inside the garage.

My inclination is to remove these wooden planks (they're painted red for cosmetic reasons burn not treated) and install some sort of waterproof barrier between them and the support beams in the garage.

There is a blue material visible when looking up at the roof of the garage when inside. It's everywhere but on this end that's getting damp. I imagine it's waterproofing? The words on t read klober span.

Does this all sound about right? Any advice?

 

[Cellophaneskies]

on the left you can see the untreated rear of the red painted wood from the front.

 

[datarebal]

Its a very flat pitch anyway with small tile headlaps. But without seeing any other pics it appears to be entering via the verge under and over the undercloak. I expect its damp under the tiles elsewhere though.