I have four sagging rafters in garage in my 1952 home. They are 2x6 and all side by side. All four have knots in about the same location, resulting in sagging. I got 4 2x6s to sister these, but that's a lot of weight to add side by side. So, Im thinking of using angle iron, as least for two of them.
Thoughts?

4/12 pitch. 12.5' rafter length. Single layer of shingles, which will be removed and replaced soon. House has no trusses or rafter ties. I will be adding a few rafter and collar ties.

tks,
pa

Rafters or roof joists? If rafters, just sister 2X8. Free span 2X6 at 12.5 ft. will sag.

Bracing is not an option ?

Bracing is not an option ?

I believe that sistering is the best option.