Approximately 35 years ago the previous owner of our home had a stump removed in order to open up the storage/utility area under the house. When they did it, they bolted a piece of 150mm x 10mm flat steel bar on both sides of the existing 140mm x 75mm timber bearer. The steel spans from stump to stump, approximately 5.8m. It is bolted with 8mm or 10mm bolts every 1000mm.
I ran a string line across and the beam has sagged about 15-20mm in the centre where the stump used to be. Real pain in the backside as there happens to be 3 bedroom doors and 4 built in robes/cupboards over this area so the doors all look out of whack.
There is one load bearing wall almost right in the centre of the beam over where the stump used to be.
I want to straighten it, and I am just narrowing down what to do.
Option 1 - retain existing 150x10 flat bar
Jack it up with an acroprop, get it level and leave acroprop in for a week or two to let the steel adjust, remove old bolts, install new thicker gauge bolts (say 12mm), and install new additional bolts between each existing one (so bolt spacings will be 500mm).
Option 2 - new angle
Jack it up with an acroprop, remove old bolts and flat bar, replace with new 125x75x10 steel angle both sides with 12mm bolts at 600mm spacings (offset bolts one towards top of beam, next towards bottom etc).
I know that I should be asking a structural engineer, and I probably will before I bite the bullet and do it, but just looking for general thoughts on the issue before I go further.