I am in the process of remodeling a house built in the late 1930. I just noticed that the floor are sagging about 1 inch on a span of 16 feet. The joist are 2x6 sistered with a 2x4 with a span of around 9 feet. The floors above are oak floors that I would like to salvage. I have several alternatives : 1) Put a 10 inch LVL beam across the whole house in the middle of the span and raise the joist by 1 inch using jacks. 2) Tear the whole floor and sister a 2x6 LVL beam next to the other joist. 3) Put a 10 inch LVL beam across the whole house in the middle and leave the joist as is.
Any one have any ideas? Please advise.

Thanks for the help.

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