You can use the two angled wood beams to protect things from rain damage, since these items appear to be classified as "roofs" so they don't take damage and will protect whatever is underneath it.

However, it doesn't work for the brazier or fires. Fire seems to go out from rain based upon whether it is classified as "sheltered" versus just covered by a roof piece.

Just an example of using the angled wood pieces. This structure suffers no rain damage and protects the non-roof pieces below it.

https://steamcommunity.com/sharedfiles/filedetails/?id=2592205105