Some odd reason I can no longer connect via facebook and this is my third? account...anywho...my issue..

I have two pier beams that are rotted under my single story 1000sqft +/- house. I know the center of the house has sunk and in one place near 3". I am planning on replacing them here soon.

I am/was trying to find a way to figure out the amount of sag in the center of the house with out having to run a string from the rear top plate to the front top plate along the ceiling joists...my thought was to nail a string with a line level from an un sagged wall and run it level to the sagged wall to get the amount of sag....so I attach it at say 52" and run it to the sagged wall, at level it reads say 51 1/2"....I know the wall doesn't need to go down...so does it mean it needs to come up a 1/2"?

I think I am just confusing myself with numbers but want to confirm...

One more quick question. The beams(photo attached) appear to be old(very old!) 8x8 beams. I am wondering since it is a single story home less the 1000sqft, can this beam be down graded to something else? I am planning on sandwiching 4 2x8x16's pressure treated together to replace them but if I can replace it with something smaller say 6x6 it may save some $$...

 

All you numbers came up as hieroglphics .
Does not matter, that main beam is shot and needs to be replaced.
6 X 6's have almost no side load strength, there going to sag.
Going to need at least a tripled up main beam.
Every time I work on a home that old I always find there's not enough piers, and improper footings so we had to take care of that first.

 

That is odd, I don't know why my post looks like I wrote it in html code...I think I cleaned it up now...

Yeah I am planning on the 4 2x8's to replace this, so I would technically be replacing it with another 8x8 but just using 2x8's to build it. I see why now a 6x6 won't work.

I am sure I need more piers, the floor joists are also 2x8 and span 15ft. My thoughts are that once everything is restored to get a foundation company out here to tidy it all up. I literally think every floor joist is rotted and needs to be sistered. Funny thing is, I had a termite guy over and he's like...oh that beam is fine, there is a lot of meat left on it...I tried not to laugh...It literally is just dirt molded to look like a beam...

Cleaned up a bit of it a few weeks ago, smoke stack was supported with 4 2x8 pieces laid flat!